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This is /home/vagrant/rpmbuild/BUILD/build-eglibc/manual/libc.info,
produced by makeinfo version 4.13 from libc.texinfo.
INFO-DIR-SECTION Software libraries
START-INFO-DIR-ENTRY
* Libc: (libc). C library.
END-INFO-DIR-ENTRY
INFO-DIR-SECTION GNU C library functions and macros
START-INFO-DIR-ENTRY
* ALTWERASE: (libc)Local Modes.
* ARGP_ERR_UNKNOWN: (libc)Argp Parser Functions.
* ARG_MAX: (libc)General Limits.
* BC_BASE_MAX: (libc)Utility Limits.
* BC_DIM_MAX: (libc)Utility Limits.
* BC_SCALE_MAX: (libc)Utility Limits.
* BC_STRING_MAX: (libc)Utility Limits.
* BRKINT: (libc)Input Modes.
* BUFSIZ: (libc)Controlling Buffering.
* CCTS_OFLOW: (libc)Control Modes.
* CHILD_MAX: (libc)General Limits.
* CIGNORE: (libc)Control Modes.
* CLK_TCK: (libc)Processor Time.
* CLOCAL: (libc)Control Modes.
* CLOCKS_PER_SEC: (libc)CPU Time.
* COLL_WEIGHTS_MAX: (libc)Utility Limits.
* CPU_CLR: (libc)CPU Affinity.
* CPU_ISSET: (libc)CPU Affinity.
* CPU_SET: (libc)CPU Affinity.
* CPU_SETSIZE: (libc)CPU Affinity.
* CPU_ZERO: (libc)CPU Affinity.
* CREAD: (libc)Control Modes.
* CRTS_IFLOW: (libc)Control Modes.
* CS5: (libc)Control Modes.
* CS6: (libc)Control Modes.
* CS7: (libc)Control Modes.
* CS8: (libc)Control Modes.
* CSIZE: (libc)Control Modes.
* CSTOPB: (libc)Control Modes.
* DES_FAILED: (libc)DES Encryption.
* DTTOIF: (libc)Directory Entries.
* E2BIG: (libc)Error Codes.
* EACCES: (libc)Error Codes.
* EADDRINUSE: (libc)Error Codes.
* EADDRNOTAVAIL: (libc)Error Codes.
* EADV: (libc)Error Codes.
* EAFNOSUPPORT: (libc)Error Codes.
* EAGAIN: (libc)Error Codes.
* EALREADY: (libc)Error Codes.
* EAUTH: (libc)Error Codes.
* EBACKGROUND: (libc)Error Codes.
* EBADE: (libc)Error Codes.
* EBADF: (libc)Error Codes.
* EBADFD: (libc)Error Codes.
* EBADMSG: (libc)Error Codes.
* EBADR: (libc)Error Codes.
* EBADRPC: (libc)Error Codes.
* EBADRQC: (libc)Error Codes.
* EBADSLT: (libc)Error Codes.
* EBFONT: (libc)Error Codes.
* EBUSY: (libc)Error Codes.
* ECANCELED: (libc)Error Codes.
* ECHILD: (libc)Error Codes.
* ECHO: (libc)Local Modes.
* ECHOCTL: (libc)Local Modes.
* ECHOE: (libc)Local Modes.
* ECHOK: (libc)Local Modes.
* ECHOKE: (libc)Local Modes.
* ECHONL: (libc)Local Modes.
* ECHOPRT: (libc)Local Modes.
* ECHRNG: (libc)Error Codes.
* ECOMM: (libc)Error Codes.
* ECONNABORTED: (libc)Error Codes.
* ECONNREFUSED: (libc)Error Codes.
* ECONNRESET: (libc)Error Codes.
* ED: (libc)Error Codes.
* EDEADLK: (libc)Error Codes.
* EDEADLOCK: (libc)Error Codes.
* EDESTADDRREQ: (libc)Error Codes.
* EDIED: (libc)Error Codes.
* EDOM: (libc)Error Codes.
* EDOTDOT: (libc)Error Codes.
* EDQUOT: (libc)Error Codes.
* EEXIST: (libc)Error Codes.
* EFAULT: (libc)Error Codes.
* EFBIG: (libc)Error Codes.
* EFTYPE: (libc)Error Codes.
* EGRATUITOUS: (libc)Error Codes.
* EGREGIOUS: (libc)Error Codes.
* EHOSTDOWN: (libc)Error Codes.
* EHOSTUNREACH: (libc)Error Codes.
* EHWPOISON: (libc)Error Codes.
* EIDRM: (libc)Error Codes.
* EIEIO: (libc)Error Codes.
* EILSEQ: (libc)Error Codes.
* EINPROGRESS: (libc)Error Codes.
* EINTR: (libc)Error Codes.
* EINVAL: (libc)Error Codes.
* EIO: (libc)Error Codes.
* EISCONN: (libc)Error Codes.
* EISDIR: (libc)Error Codes.
* EISNAM: (libc)Error Codes.
* EKEYEXPIRED: (libc)Error Codes.
* EKEYREJECTED: (libc)Error Codes.
* EKEYREVOKED: (libc)Error Codes.
* EL2HLT: (libc)Error Codes.
* EL2NSYNC: (libc)Error Codes.
* EL3HLT: (libc)Error Codes.
* EL3RST: (libc)Error Codes.
* ELIBACC: (libc)Error Codes.
* ELIBBAD: (libc)Error Codes.
* ELIBEXEC: (libc)Error Codes.
* ELIBMAX: (libc)Error Codes.
* ELIBSCN: (libc)Error Codes.
* ELNRNG: (libc)Error Codes.
* ELOOP: (libc)Error Codes.
* EMEDIUMTYPE: (libc)Error Codes.
* EMFILE: (libc)Error Codes.
* EMLINK: (libc)Error Codes.
* EMSGSIZE: (libc)Error Codes.
* EMULTIHOP: (libc)Error Codes.
* ENAMETOOLONG: (libc)Error Codes.
* ENAVAIL: (libc)Error Codes.
* ENEEDAUTH: (libc)Error Codes.
* ENETDOWN: (libc)Error Codes.
* ENETRESET: (libc)Error Codes.
* ENETUNREACH: (libc)Error Codes.
* ENFILE: (libc)Error Codes.
* ENOANO: (libc)Error Codes.
* ENOBUFS: (libc)Error Codes.
* ENOCSI: (libc)Error Codes.
* ENODATA: (libc)Error Codes.
* ENODEV: (libc)Error Codes.
* ENOENT: (libc)Error Codes.
* ENOEXEC: (libc)Error Codes.
* ENOKEY: (libc)Error Codes.
* ENOLCK: (libc)Error Codes.
* ENOLINK: (libc)Error Codes.
* ENOMEDIUM: (libc)Error Codes.
* ENOMEM: (libc)Error Codes.
* ENOMSG: (libc)Error Codes.
* ENONET: (libc)Error Codes.
* ENOPKG: (libc)Error Codes.
* ENOPROTOOPT: (libc)Error Codes.
* ENOSPC: (libc)Error Codes.
* ENOSR: (libc)Error Codes.
* ENOSTR: (libc)Error Codes.
* ENOSYS: (libc)Error Codes.
* ENOTBLK: (libc)Error Codes.
* ENOTCONN: (libc)Error Codes.
* ENOTDIR: (libc)Error Codes.
* ENOTEMPTY: (libc)Error Codes.
* ENOTNAM: (libc)Error Codes.
* ENOTRECOVERABLE: (libc)Error Codes.
* ENOTSOCK: (libc)Error Codes.
* ENOTSUP: (libc)Error Codes.
* ENOTTY: (libc)Error Codes.
* ENOTUNIQ: (libc)Error Codes.
* ENXIO: (libc)Error Codes.
* EOF: (libc)EOF and Errors.
* EOPNOTSUPP: (libc)Error Codes.
* EOVERFLOW: (libc)Error Codes.
* EOWNERDEAD: (libc)Error Codes.
* EPERM: (libc)Error Codes.
* EPFNOSUPPORT: (libc)Error Codes.
* EPIPE: (libc)Error Codes.
* EPROCLIM: (libc)Error Codes.
* EPROCUNAVAIL: (libc)Error Codes.
* EPROGMISMATCH: (libc)Error Codes.
* EPROGUNAVAIL: (libc)Error Codes.
* EPROTO: (libc)Error Codes.
* EPROTONOSUPPORT: (libc)Error Codes.
* EPROTOTYPE: (libc)Error Codes.
* EQUIV_CLASS_MAX: (libc)Utility Limits.
* ERANGE: (libc)Error Codes.
* EREMCHG: (libc)Error Codes.
* EREMOTE: (libc)Error Codes.
* EREMOTEIO: (libc)Error Codes.
* ERESTART: (libc)Error Codes.
* ERFKILL: (libc)Error Codes.
* EROFS: (libc)Error Codes.
* ERPCMISMATCH: (libc)Error Codes.
* ESHUTDOWN: (libc)Error Codes.
* ESOCKTNOSUPPORT: (libc)Error Codes.
* ESPIPE: (libc)Error Codes.
* ESRCH: (libc)Error Codes.
* ESRMNT: (libc)Error Codes.
* ESTALE: (libc)Error Codes.
* ESTRPIPE: (libc)Error Codes.
* ETIME: (libc)Error Codes.
* ETIMEDOUT: (libc)Error Codes.
* ETOOMANYREFS: (libc)Error Codes.
* ETXTBSY: (libc)Error Codes.
* EUCLEAN: (libc)Error Codes.
* EUNATCH: (libc)Error Codes.
* EUSERS: (libc)Error Codes.
* EWOULDBLOCK: (libc)Error Codes.
* EXDEV: (libc)Error Codes.
* EXFULL: (libc)Error Codes.
* EXIT_FAILURE: (libc)Exit Status.
* EXIT_SUCCESS: (libc)Exit Status.
* EXPR_NEST_MAX: (libc)Utility Limits.
* FD_CLOEXEC: (libc)Descriptor Flags.
* FD_CLR: (libc)Waiting for I/O.
* FD_ISSET: (libc)Waiting for I/O.
* FD_SET: (libc)Waiting for I/O.
* FD_SETSIZE: (libc)Waiting for I/O.
* FD_ZERO: (libc)Waiting for I/O.
* FILENAME_MAX: (libc)Limits for Files.
* FLUSHO: (libc)Local Modes.
* FOPEN_MAX: (libc)Opening Streams.
* FP_ILOGB0: (libc)Exponents and Logarithms.
* FP_ILOGBNAN: (libc)Exponents and Logarithms.
* F_DUPFD: (libc)Duplicating Descriptors.
* F_GETFD: (libc)Descriptor Flags.
* F_GETFL: (libc)Getting File Status Flags.
* F_GETLK: (libc)File Locks.
* F_GETOWN: (libc)Interrupt Input.
* F_OK: (libc)Testing File Access.
* F_SETFD: (libc)Descriptor Flags.
* F_SETFL: (libc)Getting File Status Flags.
* F_SETLK: (libc)File Locks.
* F_SETLKW: (libc)File Locks.
* F_SETOWN: (libc)Interrupt Input.
* HUGE_VAL: (libc)Math Error Reporting.
* HUGE_VALF: (libc)Math Error Reporting.
* HUGE_VALL: (libc)Math Error Reporting.
* HUPCL: (libc)Control Modes.
* I: (libc)Complex Numbers.
* ICANON: (libc)Local Modes.
* ICRNL: (libc)Input Modes.
* IEXTEN: (libc)Local Modes.
* IFNAMSIZ: (libc)Interface Naming.
* IFTODT: (libc)Directory Entries.
* IGNBRK: (libc)Input Modes.
* IGNCR: (libc)Input Modes.
* IGNPAR: (libc)Input Modes.
* IMAXBEL: (libc)Input Modes.
* INADDR_ANY: (libc)Host Address Data Type.
* INADDR_BROADCAST: (libc)Host Address Data Type.
* INADDR_LOOPBACK: (libc)Host Address Data Type.
* INADDR_NONE: (libc)Host Address Data Type.
* INFINITY: (libc)Infinity and NaN.
* INLCR: (libc)Input Modes.
* INPCK: (libc)Input Modes.
* IPPORT_RESERVED: (libc)Ports.
* IPPORT_USERRESERVED: (libc)Ports.
* ISIG: (libc)Local Modes.
* ISTRIP: (libc)Input Modes.
* IXANY: (libc)Input Modes.
* IXOFF: (libc)Input Modes.
* IXON: (libc)Input Modes.
* LINE_MAX: (libc)Utility Limits.
* LINK_MAX: (libc)Limits for Files.
* L_ctermid: (libc)Identifying the Terminal.
* L_cuserid: (libc)Who Logged In.
* L_tmpnam: (libc)Temporary Files.
* MAXNAMLEN: (libc)Limits for Files.
* MAXSYMLINKS: (libc)Symbolic Links.
* MAX_CANON: (libc)Limits for Files.
* MAX_INPUT: (libc)Limits for Files.
* MB_CUR_MAX: (libc)Selecting the Conversion.
* MB_LEN_MAX: (libc)Selecting the Conversion.
* MDMBUF: (libc)Control Modes.
* MSG_DONTROUTE: (libc)Socket Data Options.
* MSG_OOB: (libc)Socket Data Options.
* MSG_PEEK: (libc)Socket Data Options.
* NAME_MAX: (libc)Limits for Files.
* NAN: (libc)Infinity and NaN.
* NCCS: (libc)Mode Data Types.
* NGROUPS_MAX: (libc)General Limits.
* NOFLSH: (libc)Local Modes.
* NOKERNINFO: (libc)Local Modes.
* NSIG: (libc)Standard Signals.
* NULL: (libc)Null Pointer Constant.
* ONLCR: (libc)Output Modes.
* ONOEOT: (libc)Output Modes.
* OPEN_MAX: (libc)General Limits.
* OPOST: (libc)Output Modes.
* OXTABS: (libc)Output Modes.
* O_ACCMODE: (libc)Access Modes.
* O_APPEND: (libc)Operating Modes.
* O_ASYNC: (libc)Operating Modes.
* O_CREAT: (libc)Open-time Flags.
* O_EXCL: (libc)Open-time Flags.
* O_EXEC: (libc)Access Modes.
* O_EXLOCK: (libc)Open-time Flags.
* O_FSYNC: (libc)Operating Modes.
* O_IGNORE_CTTY: (libc)Open-time Flags.
* O_NDELAY: (libc)Operating Modes.
* O_NOATIME: (libc)Operating Modes.
* O_NOCTTY: (libc)Open-time Flags.
* O_NOLINK: (libc)Open-time Flags.
* O_NONBLOCK: (libc)Open-time Flags.
* O_NONBLOCK: (libc)Operating Modes.
* O_NOTRANS: (libc)Open-time Flags.
* O_RDONLY: (libc)Access Modes.
* O_RDWR: (libc)Access Modes.
* O_READ: (libc)Access Modes.
* O_SHLOCK: (libc)Open-time Flags.
* O_SYNC: (libc)Operating Modes.
* O_TRUNC: (libc)Open-time Flags.
* O_WRITE: (libc)Access Modes.
* O_WRONLY: (libc)Access Modes.
* PARENB: (libc)Control Modes.
* PARMRK: (libc)Input Modes.
* PARODD: (libc)Control Modes.
* PATH_MAX: (libc)Limits for Files.
* PA_FLAG_MASK: (libc)Parsing a Template String.
* PENDIN: (libc)Local Modes.
* PF_FILE: (libc)Local Namespace Details.
* PF_INET6: (libc)Internet Namespace.
* PF_INET: (libc)Internet Namespace.
* PF_LOCAL: (libc)Local Namespace Details.
* PF_UNIX: (libc)Local Namespace Details.
* PIPE_BUF: (libc)Limits for Files.
* P_tmpdir: (libc)Temporary Files.
* RAND_MAX: (libc)ISO Random.
* RE_DUP_MAX: (libc)General Limits.
* RLIM_INFINITY: (libc)Limits on Resources.
* R_OK: (libc)Testing File Access.
* SA_NOCLDSTOP: (libc)Flags for Sigaction.
* SA_ONSTACK: (libc)Flags for Sigaction.
* SA_RESTART: (libc)Flags for Sigaction.
* SEEK_CUR: (libc)File Positioning.
* SEEK_END: (libc)File Positioning.
* SEEK_SET: (libc)File Positioning.
* SIGABRT: (libc)Program Error Signals.
* SIGALRM: (libc)Alarm Signals.
* SIGBUS: (libc)Program Error Signals.
* SIGCHLD: (libc)Job Control Signals.
* SIGCLD: (libc)Job Control Signals.
* SIGCONT: (libc)Job Control Signals.
* SIGEMT: (libc)Program Error Signals.
* SIGFPE: (libc)Program Error Signals.
* SIGHUP: (libc)Termination Signals.
* SIGILL: (libc)Program Error Signals.
* SIGINFO: (libc)Miscellaneous Signals.
* SIGINT: (libc)Termination Signals.
* SIGIO: (libc)Asynchronous I/O Signals.
* SIGIOT: (libc)Program Error Signals.
* SIGKILL: (libc)Termination Signals.
* SIGLOST: (libc)Operation Error Signals.
* SIGPIPE: (libc)Operation Error Signals.
* SIGPOLL: (libc)Asynchronous I/O Signals.
* SIGPROF: (libc)Alarm Signals.
* SIGQUIT: (libc)Termination Signals.
* SIGSEGV: (libc)Program Error Signals.
* SIGSTOP: (libc)Job Control Signals.
* SIGSYS: (libc)Program Error Signals.
* SIGTERM: (libc)Termination Signals.
* SIGTRAP: (libc)Program Error Signals.
* SIGTSTP: (libc)Job Control Signals.
* SIGTTIN: (libc)Job Control Signals.
* SIGTTOU: (libc)Job Control Signals.
* SIGURG: (libc)Asynchronous I/O Signals.
* SIGUSR1: (libc)Miscellaneous Signals.
* SIGUSR2: (libc)Miscellaneous Signals.
* SIGVTALRM: (libc)Alarm Signals.
* SIGWINCH: (libc)Miscellaneous Signals.
* SIGXCPU: (libc)Operation Error Signals.
* SIGXFSZ: (libc)Operation Error Signals.
* SIG_ERR: (libc)Basic Signal Handling.
* SOCK_DGRAM: (libc)Communication Styles.
* SOCK_RAW: (libc)Communication Styles.
* SOCK_RDM: (libc)Communication Styles.
* SOCK_SEQPACKET: (libc)Communication Styles.
* SOCK_STREAM: (libc)Communication Styles.
* SOL_SOCKET: (libc)Socket-Level Options.
* SSIZE_MAX: (libc)General Limits.
* STREAM_MAX: (libc)General Limits.
* SUN_LEN: (libc)Local Namespace Details.
* SV_INTERRUPT: (libc)BSD Handler.
* SV_ONSTACK: (libc)BSD Handler.
* SV_RESETHAND: (libc)BSD Handler.
* S_IFMT: (libc)Testing File Type.
* S_ISBLK: (libc)Testing File Type.
* S_ISCHR: (libc)Testing File Type.
* S_ISDIR: (libc)Testing File Type.
* S_ISFIFO: (libc)Testing File Type.
* S_ISLNK: (libc)Testing File Type.
* S_ISREG: (libc)Testing File Type.
* S_ISSOCK: (libc)Testing File Type.
* S_TYPEISMQ: (libc)Testing File Type.
* S_TYPEISSEM: (libc)Testing File Type.
* S_TYPEISSHM: (libc)Testing File Type.
* TMP_MAX: (libc)Temporary Files.
* TOSTOP: (libc)Local Modes.
* TZNAME_MAX: (libc)General Limits.
* VDISCARD: (libc)Other Special.
* VDSUSP: (libc)Signal Characters.
* VEOF: (libc)Editing Characters.
* VEOL2: (libc)Editing Characters.
* VEOL: (libc)Editing Characters.
* VERASE: (libc)Editing Characters.
* VINTR: (libc)Signal Characters.
* VKILL: (libc)Editing Characters.
* VLNEXT: (libc)Other Special.
* VMIN: (libc)Noncanonical Input.
* VQUIT: (libc)Signal Characters.
* VREPRINT: (libc)Editing Characters.
* VSTART: (libc)Start/Stop Characters.
* VSTATUS: (libc)Other Special.
* VSTOP: (libc)Start/Stop Characters.
* VSUSP: (libc)Signal Characters.
* VTIME: (libc)Noncanonical Input.
* VWERASE: (libc)Editing Characters.
* WCHAR_MAX: (libc)Extended Char Intro.
* WCHAR_MIN: (libc)Extended Char Intro.
* WCOREDUMP: (libc)Process Completion Status.
* WEOF: (libc)EOF and Errors.
* WEOF: (libc)Extended Char Intro.
* WEXITSTATUS: (libc)Process Completion Status.
* WIFEXITED: (libc)Process Completion Status.
* WIFSIGNALED: (libc)Process Completion Status.
* WIFSTOPPED: (libc)Process Completion Status.
* WSTOPSIG: (libc)Process Completion Status.
* WTERMSIG: (libc)Process Completion Status.
* W_OK: (libc)Testing File Access.
* X_OK: (libc)Testing File Access.
* _Complex_I: (libc)Complex Numbers.
* _Exit: (libc)Termination Internals.
* _IOFBF: (libc)Controlling Buffering.
* _IOLBF: (libc)Controlling Buffering.
* _IONBF: (libc)Controlling Buffering.
* _Imaginary_I: (libc)Complex Numbers.
* _PATH_UTMP: (libc)Manipulating the Database.
* _PATH_WTMP: (libc)Manipulating the Database.
* _POSIX2_C_DEV: (libc)System Options.
* _POSIX2_C_VERSION: (libc)Version Supported.
* _POSIX2_FORT_DEV: (libc)System Options.
* _POSIX2_FORT_RUN: (libc)System Options.
* _POSIX2_LOCALEDEF: (libc)System Options.
* _POSIX2_SW_DEV: (libc)System Options.
* _POSIX_CHOWN_RESTRICTED: (libc)Options for Files.
* _POSIX_JOB_CONTROL: (libc)System Options.
* _POSIX_NO_TRUNC: (libc)Options for Files.
* _POSIX_SAVED_IDS: (libc)System Options.
* _POSIX_VDISABLE: (libc)Options for Files.
* _POSIX_VERSION: (libc)Version Supported.
* __fbufsize: (libc)Controlling Buffering.
* __flbf: (libc)Controlling Buffering.
* __fpending: (libc)Controlling Buffering.
* __fpurge: (libc)Flushing Buffers.
* __freadable: (libc)Opening Streams.
* __freading: (libc)Opening Streams.
* __fsetlocking: (libc)Streams and Threads.
* __fwritable: (libc)Opening Streams.
* __fwriting: (libc)Opening Streams.
* __gconv_end_fct: (libc)glibc iconv Implementation.
* __gconv_fct: (libc)glibc iconv Implementation.
* __gconv_init_fct: (libc)glibc iconv Implementation.
* __ppc_get_timebase: (libc)PowerPC.
* __ppc_get_timebase_freq: (libc)PowerPC.
* __ppc_mdoio: (libc)PowerPC.
* __ppc_mdoom: (libc)PowerPC.
* __ppc_set_ppr_low: (libc)PowerPC.
* __ppc_set_ppr_med: (libc)PowerPC.
* __ppc_set_ppr_med_low: (libc)PowerPC.
* __ppc_yield: (libc)PowerPC.
* __va_copy: (libc)Argument Macros.
* _exit: (libc)Termination Internals.
* _flushlbf: (libc)Flushing Buffers.
* _tolower: (libc)Case Conversion.
* _toupper: (libc)Case Conversion.
* a64l: (libc)Encode Binary Data.
* abort: (libc)Aborting a Program.
* abs: (libc)Absolute Value.
* accept: (libc)Accepting Connections.
* access: (libc)Testing File Access.
* acos: (libc)Inverse Trig Functions.
* acosf: (libc)Inverse Trig Functions.
* acosh: (libc)Hyperbolic Functions.
* acoshf: (libc)Hyperbolic Functions.
* acoshl: (libc)Hyperbolic Functions.
* acosl: (libc)Inverse Trig Functions.
* addmntent: (libc)mtab.
* addseverity: (libc)Adding Severity Classes.
* adjtime: (libc)High-Resolution Calendar.
* adjtimex: (libc)High-Resolution Calendar.
* aio_cancel64: (libc)Cancel AIO Operations.
* aio_cancel: (libc)Cancel AIO Operations.
* aio_error64: (libc)Status of AIO Operations.
* aio_error: (libc)Status of AIO Operations.
* aio_fsync64: (libc)Synchronizing AIO Operations.
* aio_fsync: (libc)Synchronizing AIO Operations.
* aio_init: (libc)Configuration of AIO.
* aio_read64: (libc)Asynchronous Reads/Writes.
* aio_read: (libc)Asynchronous Reads/Writes.
* aio_return64: (libc)Status of AIO Operations.
* aio_return: (libc)Status of AIO Operations.
* aio_suspend64: (libc)Synchronizing AIO Operations.
* aio_suspend: (libc)Synchronizing AIO Operations.
* aio_write64: (libc)Asynchronous Reads/Writes.
* aio_write: (libc)Asynchronous Reads/Writes.
* alarm: (libc)Setting an Alarm.
* alloca: (libc)Variable Size Automatic.
* alphasort64: (libc)Scanning Directory Content.
* alphasort: (libc)Scanning Directory Content.
* argp_error: (libc)Argp Helper Functions.
* argp_failure: (libc)Argp Helper Functions.
* argp_help: (libc)Argp Help.
* argp_parse: (libc)Argp.
* argp_state_help: (libc)Argp Helper Functions.
* argp_usage: (libc)Argp Helper Functions.
* argz_add: (libc)Argz Functions.
* argz_add_sep: (libc)Argz Functions.
* argz_append: (libc)Argz Functions.
* argz_count: (libc)Argz Functions.
* argz_create: (libc)Argz Functions.
* argz_create_sep: (libc)Argz Functions.
* argz_delete: (libc)Argz Functions.
* argz_extract: (libc)Argz Functions.
* argz_insert: (libc)Argz Functions.
* argz_next: (libc)Argz Functions.
* argz_replace: (libc)Argz Functions.
* argz_stringify: (libc)Argz Functions.
* asctime: (libc)Formatting Calendar Time.
* asctime_r: (libc)Formatting Calendar Time.
* asin: (libc)Inverse Trig Functions.
* asinf: (libc)Inverse Trig Functions.
* asinh: (libc)Hyperbolic Functions.
* asinhf: (libc)Hyperbolic Functions.
* asinhl: (libc)Hyperbolic Functions.
* asinl: (libc)Inverse Trig Functions.
* asprintf: (libc)Dynamic Output.
* assert: (libc)Consistency Checking.
* assert_perror: (libc)Consistency Checking.
* atan2: (libc)Inverse Trig Functions.
* atan2f: (libc)Inverse Trig Functions.
* atan2l: (libc)Inverse Trig Functions.
* atan: (libc)Inverse Trig Functions.
* atanf: (libc)Inverse Trig Functions.
* atanh: (libc)Hyperbolic Functions.
* atanhf: (libc)Hyperbolic Functions.
* atanhl: (libc)Hyperbolic Functions.
* atanl: (libc)Inverse Trig Functions.
* atexit: (libc)Cleanups on Exit.
* atof: (libc)Parsing of Floats.
* atoi: (libc)Parsing of Integers.
* atol: (libc)Parsing of Integers.
* atoll: (libc)Parsing of Integers.
* backtrace: (libc)Backtraces.
* backtrace_symbols: (libc)Backtraces.
* backtrace_symbols_fd: (libc)Backtraces.
* basename: (libc)Finding Tokens in a String.
* basename: (libc)Finding Tokens in a String.
* bcmp: (libc)String/Array Comparison.
* bcopy: (libc)Copying and Concatenation.
* bind: (libc)Setting Address.
* bind_textdomain_codeset: (libc)Charset conversion in gettext.
* bindtextdomain: (libc)Locating gettext catalog.
* brk: (libc)Resizing the Data Segment.
* bsearch: (libc)Array Search Function.
* btowc: (libc)Converting a Character.
* bzero: (libc)Copying and Concatenation.
* cabs: (libc)Absolute Value.
* cabsf: (libc)Absolute Value.
* cabsl: (libc)Absolute Value.
* cacos: (libc)Inverse Trig Functions.
* cacosf: (libc)Inverse Trig Functions.
* cacosh: (libc)Hyperbolic Functions.
* cacoshf: (libc)Hyperbolic Functions.
* cacoshl: (libc)Hyperbolic Functions.
* cacosl: (libc)Inverse Trig Functions.
* calloc: (libc)Allocating Cleared Space.
* canonicalize_file_name: (libc)Symbolic Links.
* carg: (libc)Operations on Complex.
* cargf: (libc)Operations on Complex.
* cargl: (libc)Operations on Complex.
* casin: (libc)Inverse Trig Functions.
* casinf: (libc)Inverse Trig Functions.
* casinh: (libc)Hyperbolic Functions.
* casinhf: (libc)Hyperbolic Functions.
* casinhl: (libc)Hyperbolic Functions.
* casinl: (libc)Inverse Trig Functions.
* catan: (libc)Inverse Trig Functions.
* catanf: (libc)Inverse Trig Functions.
* catanh: (libc)Hyperbolic Functions.
* catanhf: (libc)Hyperbolic Functions.
* catanhl: (libc)Hyperbolic Functions.
* catanl: (libc)Inverse Trig Functions.
* catclose: (libc)The catgets Functions.
* catgets: (libc)The catgets Functions.
* catopen: (libc)The catgets Functions.
* cbc_crypt: (libc)DES Encryption.
* cbrt: (libc)Exponents and Logarithms.
* cbrtf: (libc)Exponents and Logarithms.
* cbrtl: (libc)Exponents and Logarithms.
* ccos: (libc)Trig Functions.
* ccosf: (libc)Trig Functions.
* ccosh: (libc)Hyperbolic Functions.
* ccoshf: (libc)Hyperbolic Functions.
* ccoshl: (libc)Hyperbolic Functions.
* ccosl: (libc)Trig Functions.
* ceil: (libc)Rounding Functions.
* ceilf: (libc)Rounding Functions.
* ceill: (libc)Rounding Functions.
* cexp: (libc)Exponents and Logarithms.
* cexpf: (libc)Exponents and Logarithms.
* cexpl: (libc)Exponents and Logarithms.
* cfgetispeed: (libc)Line Speed.
* cfgetospeed: (libc)Line Speed.
* cfmakeraw: (libc)Noncanonical Input.
* cfree: (libc)Freeing after Malloc.
* cfsetispeed: (libc)Line Speed.
* cfsetospeed: (libc)Line Speed.
* cfsetspeed: (libc)Line Speed.
* chdir: (libc)Working Directory.
* chmod: (libc)Setting Permissions.
* chown: (libc)File Owner.
* cimag: (libc)Operations on Complex.
* cimagf: (libc)Operations on Complex.
* cimagl: (libc)Operations on Complex.
* clearenv: (libc)Environment Access.
* clearerr: (libc)Error Recovery.
* clearerr_unlocked: (libc)Error Recovery.
* clock: (libc)CPU Time.
* clog10: (libc)Exponents and Logarithms.
* clog10f: (libc)Exponents and Logarithms.
* clog10l: (libc)Exponents and Logarithms.
* clog: (libc)Exponents and Logarithms.
* clogf: (libc)Exponents and Logarithms.
* clogl: (libc)Exponents and Logarithms.
* close: (libc)Opening and Closing Files.
* closedir: (libc)Reading/Closing Directory.
* closelog: (libc)closelog.
* confstr: (libc)String Parameters.
* conj: (libc)Operations on Complex.
* conjf: (libc)Operations on Complex.
* conjl: (libc)Operations on Complex.
* connect: (libc)Connecting.
* copysign: (libc)FP Bit Twiddling.
* copysignf: (libc)FP Bit Twiddling.
* copysignl: (libc)FP Bit Twiddling.
* cos: (libc)Trig Functions.
* cosf: (libc)Trig Functions.
* cosh: (libc)Hyperbolic Functions.
* coshf: (libc)Hyperbolic Functions.
* coshl: (libc)Hyperbolic Functions.
* cosl: (libc)Trig Functions.
* cpow: (libc)Exponents and Logarithms.
* cpowf: (libc)Exponents and Logarithms.
* cpowl: (libc)Exponents and Logarithms.
* cproj: (libc)Operations on Complex.
* cprojf: (libc)Operations on Complex.
* cprojl: (libc)Operations on Complex.
* creal: (libc)Operations on Complex.
* crealf: (libc)Operations on Complex.
* creall: (libc)Operations on Complex.
* creat64: (libc)Opening and Closing Files.
* creat: (libc)Opening and Closing Files.
* crypt: (libc)crypt.
* crypt_r: (libc)crypt.
* csin: (libc)Trig Functions.
* csinf: (libc)Trig Functions.
* csinh: (libc)Hyperbolic Functions.
* csinhf: (libc)Hyperbolic Functions.
* csinhl: (libc)Hyperbolic Functions.
* csinl: (libc)Trig Functions.
* csqrt: (libc)Exponents and Logarithms.
* csqrtf: (libc)Exponents and Logarithms.
* csqrtl: (libc)Exponents and Logarithms.
* ctan: (libc)Trig Functions.
* ctanf: (libc)Trig Functions.
* ctanh: (libc)Hyperbolic Functions.
* ctanhf: (libc)Hyperbolic Functions.
* ctanhl: (libc)Hyperbolic Functions.
* ctanl: (libc)Trig Functions.
* ctermid: (libc)Identifying the Terminal.
* ctime: (libc)Formatting Calendar Time.
* ctime_r: (libc)Formatting Calendar Time.
* cuserid: (libc)Who Logged In.
* dcgettext: (libc)Translation with gettext.
* dcngettext: (libc)Advanced gettext functions.
* des_setparity: (libc)DES Encryption.
* dgettext: (libc)Translation with gettext.
* difftime: (libc)Elapsed Time.
* dirfd: (libc)Opening a Directory.
* dirname: (libc)Finding Tokens in a String.
* div: (libc)Integer Division.
* dngettext: (libc)Advanced gettext functions.
* drand48: (libc)SVID Random.
* drand48_r: (libc)SVID Random.
* drem: (libc)Remainder Functions.
* dremf: (libc)Remainder Functions.
* dreml: (libc)Remainder Functions.
* dup2: (libc)Duplicating Descriptors.
* dup: (libc)Duplicating Descriptors.
* ecb_crypt: (libc)DES Encryption.
* ecvt: (libc)System V Number Conversion.
* ecvt_r: (libc)System V Number Conversion.
* encrypt: (libc)DES Encryption.
* encrypt_r: (libc)DES Encryption.
* endfsent: (libc)fstab.
* endgrent: (libc)Scanning All Groups.
* endhostent: (libc)Host Names.
* endmntent: (libc)mtab.
* endnetent: (libc)Networks Database.
* endnetgrent: (libc)Lookup Netgroup.
* endprotoent: (libc)Protocols Database.
* endpwent: (libc)Scanning All Users.
* endservent: (libc)Services Database.
* endutent: (libc)Manipulating the Database.
* endutxent: (libc)XPG Functions.
* envz_add: (libc)Envz Functions.
* envz_entry: (libc)Envz Functions.
* envz_get: (libc)Envz Functions.
* envz_merge: (libc)Envz Functions.
* envz_strip: (libc)Envz Functions.
* erand48: (libc)SVID Random.
* erand48_r: (libc)SVID Random.
* erf: (libc)Special Functions.
* erfc: (libc)Special Functions.
* erfcf: (libc)Special Functions.
* erfcl: (libc)Special Functions.
* erff: (libc)Special Functions.
* erfl: (libc)Special Functions.
* err: (libc)Error Messages.
* errno: (libc)Checking for Errors.
* error: (libc)Error Messages.
* error_at_line: (libc)Error Messages.
* errx: (libc)Error Messages.
* execl: (libc)Executing a File.
* execle: (libc)Executing a File.
* execlp: (libc)Executing a File.
* execv: (libc)Executing a File.
* execve: (libc)Executing a File.
* execvp: (libc)Executing a File.
* exit: (libc)Normal Termination.
* exp10: (libc)Exponents and Logarithms.
* exp10f: (libc)Exponents and Logarithms.
* exp10l: (libc)Exponents and Logarithms.
* exp2: (libc)Exponents and Logarithms.
* exp2f: (libc)Exponents and Logarithms.
* exp2l: (libc)Exponents and Logarithms.
* exp: (libc)Exponents and Logarithms.
* expf: (libc)Exponents and Logarithms.
* expl: (libc)Exponents and Logarithms.
* expm1: (libc)Exponents and Logarithms.
* expm1f: (libc)Exponents and Logarithms.
* expm1l: (libc)Exponents and Logarithms.
* fabs: (libc)Absolute Value.
* fabsf: (libc)Absolute Value.
* fabsl: (libc)Absolute Value.
* fchdir: (libc)Working Directory.
* fchmod: (libc)Setting Permissions.
* fchown: (libc)File Owner.
* fclose: (libc)Closing Streams.
* fcloseall: (libc)Closing Streams.
* fcntl: (libc)Control Operations.
* fcvt: (libc)System V Number Conversion.
* fcvt_r: (libc)System V Number Conversion.
* fdatasync: (libc)Synchronizing I/O.
* fdim: (libc)Misc FP Arithmetic.
* fdimf: (libc)Misc FP Arithmetic.
* fdiml: (libc)Misc FP Arithmetic.
* fdopen: (libc)Descriptors and Streams.
* fdopendir: (libc)Opening a Directory.
* feclearexcept: (libc)Status bit operations.
* fedisableexcept: (libc)Control Functions.
* feenableexcept: (libc)Control Functions.
* fegetenv: (libc)Control Functions.
* fegetexcept: (libc)Control Functions.
* fegetexceptflag: (libc)Status bit operations.
* fegetround: (libc)Rounding.
* feholdexcept: (libc)Control Functions.
* feof: (libc)EOF and Errors.
* feof_unlocked: (libc)EOF and Errors.
* feraiseexcept: (libc)Status bit operations.
* ferror: (libc)EOF and Errors.
* ferror_unlocked: (libc)EOF and Errors.
* fesetenv: (libc)Control Functions.
* fesetexceptflag: (libc)Status bit operations.
* fesetround: (libc)Rounding.
* fetestexcept: (libc)Status bit operations.
* feupdateenv: (libc)Control Functions.
* fflush: (libc)Flushing Buffers.
* fflush_unlocked: (libc)Flushing Buffers.
* fgetc: (libc)Character Input.
* fgetc_unlocked: (libc)Character Input.
* fgetgrent: (libc)Scanning All Groups.
* fgetgrent_r: (libc)Scanning All Groups.
* fgetpos64: (libc)Portable Positioning.
* fgetpos: (libc)Portable Positioning.
* fgetpwent: (libc)Scanning All Users.
* fgetpwent_r: (libc)Scanning All Users.
* fgets: (libc)Line Input.
* fgets_unlocked: (libc)Line Input.
* fgetwc: (libc)Character Input.
* fgetwc_unlocked: (libc)Character Input.
* fgetws: (libc)Line Input.
* fgetws_unlocked: (libc)Line Input.
* fileno: (libc)Descriptors and Streams.
* fileno_unlocked: (libc)Descriptors and Streams.
* finite: (libc)Floating Point Classes.
* finitef: (libc)Floating Point Classes.
* finitel: (libc)Floating Point Classes.
* flockfile: (libc)Streams and Threads.
* floor: (libc)Rounding Functions.
* floorf: (libc)Rounding Functions.
* floorl: (libc)Rounding Functions.
* fma: (libc)Misc FP Arithmetic.
* fmaf: (libc)Misc FP Arithmetic.
* fmal: (libc)Misc FP Arithmetic.
* fmax: (libc)Misc FP Arithmetic.
* fmaxf: (libc)Misc FP Arithmetic.
* fmaxl: (libc)Misc FP Arithmetic.
* fmemopen: (libc)String Streams.
* fmin: (libc)Misc FP Arithmetic.
* fminf: (libc)Misc FP Arithmetic.
* fminl: (libc)Misc FP Arithmetic.
* fmod: (libc)Remainder Functions.
* fmodf: (libc)Remainder Functions.
* fmodl: (libc)Remainder Functions.
* fmtmsg: (libc)Printing Formatted Messages.
* fnmatch: (libc)Wildcard Matching.
* fopen64: (libc)Opening Streams.
* fopen: (libc)Opening Streams.
* fopencookie: (libc)Streams and Cookies.
* fork: (libc)Creating a Process.
* forkpty: (libc)Pseudo-Terminal Pairs.
* fpathconf: (libc)Pathconf.
* fpclassify: (libc)Floating Point Classes.
* fprintf: (libc)Formatted Output Functions.
* fputc: (libc)Simple Output.
* fputc_unlocked: (libc)Simple Output.
* fputs: (libc)Simple Output.
* fputs_unlocked: (libc)Simple Output.
* fputwc: (libc)Simple Output.
* fputwc_unlocked: (libc)Simple Output.
* fputws: (libc)Simple Output.
* fputws_unlocked: (libc)Simple Output.
* fread: (libc)Block Input/Output.
* fread_unlocked: (libc)Block Input/Output.
* free: (libc)Freeing after Malloc.
* freopen64: (libc)Opening Streams.
* freopen: (libc)Opening Streams.
* frexp: (libc)Normalization Functions.
* frexpf: (libc)Normalization Functions.
* frexpl: (libc)Normalization Functions.
* fscanf: (libc)Formatted Input Functions.
* fseek: (libc)File Positioning.
* fseeko64: (libc)File Positioning.
* fseeko: (libc)File Positioning.
* fsetpos64: (libc)Portable Positioning.
* fsetpos: (libc)Portable Positioning.
* fstat64: (libc)Reading Attributes.
* fstat: (libc)Reading Attributes.
* fsync: (libc)Synchronizing I/O.
* ftell: (libc)File Positioning.
* ftello64: (libc)File Positioning.
* ftello: (libc)File Positioning.
* ftruncate64: (libc)File Size.
* ftruncate: (libc)File Size.
* ftrylockfile: (libc)Streams and Threads.
* ftw64: (libc)Working with Directory Trees.
* ftw: (libc)Working with Directory Trees.
* funlockfile: (libc)Streams and Threads.
* futimes: (libc)File Times.
* fwide: (libc)Streams and I18N.
* fwprintf: (libc)Formatted Output Functions.
* fwrite: (libc)Block Input/Output.
* fwrite_unlocked: (libc)Block Input/Output.
* fwscanf: (libc)Formatted Input Functions.
* gamma: (libc)Special Functions.
* gammaf: (libc)Special Functions.
* gammal: (libc)Special Functions.
* gcvt: (libc)System V Number Conversion.
* get_avphys_pages: (libc)Query Memory Parameters.
* get_current_dir_name: (libc)Working Directory.
* get_nprocs: (libc)Processor Resources.
* get_nprocs_conf: (libc)Processor Resources.
* get_phys_pages: (libc)Query Memory Parameters.
* getauxval: (libc)Auxiliary Vector.
* getc: (libc)Character Input.
* getc_unlocked: (libc)Character Input.
* getchar: (libc)Character Input.
* getchar_unlocked: (libc)Character Input.
* getcontext: (libc)System V contexts.
* getcwd: (libc)Working Directory.
* getdate: (libc)General Time String Parsing.
* getdate_r: (libc)General Time String Parsing.
* getdelim: (libc)Line Input.
* getdomainnname: (libc)Host Identification.
* getegid: (libc)Reading Persona.
* getenv: (libc)Environment Access.
* geteuid: (libc)Reading Persona.
* getfsent: (libc)fstab.
* getfsfile: (libc)fstab.
* getfsspec: (libc)fstab.
* getgid: (libc)Reading Persona.
* getgrent: (libc)Scanning All Groups.
* getgrent_r: (libc)Scanning All Groups.
* getgrgid: (libc)Lookup Group.
* getgrgid_r: (libc)Lookup Group.
* getgrnam: (libc)Lookup Group.
* getgrnam_r: (libc)Lookup Group.
* getgrouplist: (libc)Setting Groups.
* getgroups: (libc)Reading Persona.
* gethostbyaddr: (libc)Host Names.
* gethostbyaddr_r: (libc)Host Names.
* gethostbyname2: (libc)Host Names.
* gethostbyname2_r: (libc)Host Names.
* gethostbyname: (libc)Host Names.
* gethostbyname_r: (libc)Host Names.
* gethostent: (libc)Host Names.
* gethostid: (libc)Host Identification.
* gethostname: (libc)Host Identification.
* getitimer: (libc)Setting an Alarm.
* getline: (libc)Line Input.
* getloadavg: (libc)Processor Resources.
* getlogin: (libc)Who Logged In.
* getmntent: (libc)mtab.
* getmntent_r: (libc)mtab.
* getnetbyaddr: (libc)Networks Database.
* getnetbyname: (libc)Networks Database.
* getnetent: (libc)Networks Database.
* getnetgrent: (libc)Lookup Netgroup.
* getnetgrent_r: (libc)Lookup Netgroup.
* getopt: (libc)Using Getopt.
* getopt_long: (libc)Getopt Long Options.
* getopt_long_only: (libc)Getopt Long Options.
* getpagesize: (libc)Query Memory Parameters.
* getpass: (libc)getpass.
* getpeername: (libc)Who is Connected.
* getpgid: (libc)Process Group Functions.
* getpgrp: (libc)Process Group Functions.
* getpgrp: (libc)Process Group Functions.
* getpid: (libc)Process Identification.
* getppid: (libc)Process Identification.
* getpriority: (libc)Traditional Scheduling Functions.
* getprotobyname: (libc)Protocols Database.
* getprotobynumber: (libc)Protocols Database.
* getprotoent: (libc)Protocols Database.
* getpt: (libc)Allocation.
* getpwent: (libc)Scanning All Users.
* getpwent_r: (libc)Scanning All Users.
* getpwnam: (libc)Lookup User.
* getpwnam_r: (libc)Lookup User.
* getpwuid: (libc)Lookup User.
* getpwuid_r: (libc)Lookup User.
* getrlimit64: (libc)Limits on Resources.
* getrlimit: (libc)Limits on Resources.
* getrusage: (libc)Resource Usage.
* gets: (libc)Line Input.
* getservbyname: (libc)Services Database.
* getservbyport: (libc)Services Database.
* getservent: (libc)Services Database.
* getsid: (libc)Process Group Functions.
* getsockname: (libc)Reading Address.
* getsockopt: (libc)Socket Option Functions.
* getsubopt: (libc)Suboptions.
* gettext: (libc)Translation with gettext.
* gettimeofday: (libc)High-Resolution Calendar.
* getuid: (libc)Reading Persona.
* getumask: (libc)Setting Permissions.
* getutent: (libc)Manipulating the Database.
* getutent_r: (libc)Manipulating the Database.
* getutid: (libc)Manipulating the Database.
* getutid_r: (libc)Manipulating the Database.
* getutline: (libc)Manipulating the Database.
* getutline_r: (libc)Manipulating the Database.
* getutmp: (libc)XPG Functions.
* getutmpx: (libc)XPG Functions.
* getutxent: (libc)XPG Functions.
* getutxid: (libc)XPG Functions.
* getutxline: (libc)XPG Functions.
* getw: (libc)Character Input.
* getwc: (libc)Character Input.
* getwc_unlocked: (libc)Character Input.
* getwchar: (libc)Character Input.
* getwchar_unlocked: (libc)Character Input.
* getwd: (libc)Working Directory.
* glob64: (libc)Calling Glob.
* glob: (libc)Calling Glob.
* globfree64: (libc)More Flags for Globbing.
* globfree: (libc)More Flags for Globbing.
* gmtime: (libc)Broken-down Time.
* gmtime_r: (libc)Broken-down Time.
* grantpt: (libc)Allocation.
* gsignal: (libc)Signaling Yourself.
* gtty: (libc)BSD Terminal Modes.
* hasmntopt: (libc)mtab.
* hcreate: (libc)Hash Search Function.
* hcreate_r: (libc)Hash Search Function.
* hdestroy: (libc)Hash Search Function.
* hdestroy_r: (libc)Hash Search Function.
* hsearch: (libc)Hash Search Function.
* hsearch_r: (libc)Hash Search Function.
* htonl: (libc)Byte Order.
* htons: (libc)Byte Order.
* hypot: (libc)Exponents and Logarithms.
* hypotf: (libc)Exponents and Logarithms.
* hypotl: (libc)Exponents and Logarithms.
* iconv: (libc)Generic Conversion Interface.
* iconv_close: (libc)Generic Conversion Interface.
* iconv_open: (libc)Generic Conversion Interface.
* if_freenameindex: (libc)Interface Naming.
* if_indextoname: (libc)Interface Naming.
* if_nameindex: (libc)Interface Naming.
* if_nametoindex: (libc)Interface Naming.
* ilogb: (libc)Exponents and Logarithms.
* ilogbf: (libc)Exponents and Logarithms.
* ilogbl: (libc)Exponents and Logarithms.
* imaxabs: (libc)Absolute Value.
* imaxdiv: (libc)Integer Division.
* in6addr_any: (libc)Host Address Data Type.
* in6addr_loopback: (libc)Host Address Data Type.
* index: (libc)Search Functions.
* inet_addr: (libc)Host Address Functions.
* inet_aton: (libc)Host Address Functions.
* inet_lnaof: (libc)Host Address Functions.
* inet_makeaddr: (libc)Host Address Functions.
* inet_netof: (libc)Host Address Functions.
* inet_network: (libc)Host Address Functions.
* inet_ntoa: (libc)Host Address Functions.
* inet_ntop: (libc)Host Address Functions.
* inet_pton: (libc)Host Address Functions.
* initgroups: (libc)Setting Groups.
* initstate: (libc)BSD Random.
* initstate_r: (libc)BSD Random.
* innetgr: (libc)Netgroup Membership.
* ioctl: (libc)IOCTLs.
* isalnum: (libc)Classification of Characters.
* isalpha: (libc)Classification of Characters.
* isascii: (libc)Classification of Characters.
* isatty: (libc)Is It a Terminal.
* isblank: (libc)Classification of Characters.
* iscntrl: (libc)Classification of Characters.
* isdigit: (libc)Classification of Characters.
* isfinite: (libc)Floating Point Classes.
* isgraph: (libc)Classification of Characters.
* isgreater: (libc)FP Comparison Functions.
* isgreaterequal: (libc)FP Comparison Functions.
* isinf: (libc)Floating Point Classes.
* isinff: (libc)Floating Point Classes.
* isinfl: (libc)Floating Point Classes.
* isless: (libc)FP Comparison Functions.
* islessequal: (libc)FP Comparison Functions.
* islessgreater: (libc)FP Comparison Functions.
* islower: (libc)Classification of Characters.
* isnan: (libc)Floating Point Classes.
* isnan: (libc)Floating Point Classes.
* isnanf: (libc)Floating Point Classes.
* isnanl: (libc)Floating Point Classes.
* isnormal: (libc)Floating Point Classes.
* isprint: (libc)Classification of Characters.
* ispunct: (libc)Classification of Characters.
* issignaling: (libc)Floating Point Classes.
* isspace: (libc)Classification of Characters.
* isunordered: (libc)FP Comparison Functions.
* isupper: (libc)Classification of Characters.
* iswalnum: (libc)Classification of Wide Characters.
* iswalpha: (libc)Classification of Wide Characters.
* iswblank: (libc)Classification of Wide Characters.
* iswcntrl: (libc)Classification of Wide Characters.
* iswctype: (libc)Classification of Wide Characters.
* iswdigit: (libc)Classification of Wide Characters.
* iswgraph: (libc)Classification of Wide Characters.
* iswlower: (libc)Classification of Wide Characters.
* iswprint: (libc)Classification of Wide Characters.
* iswpunct: (libc)Classification of Wide Characters.
* iswspace: (libc)Classification of Wide Characters.
* iswupper: (libc)Classification of Wide Characters.
* iswxdigit: (libc)Classification of Wide Characters.
* isxdigit: (libc)Classification of Characters.
* j0: (libc)Special Functions.
* j0f: (libc)Special Functions.
* j0l: (libc)Special Functions.
* j1: (libc)Special Functions.
* j1f: (libc)Special Functions.
* j1l: (libc)Special Functions.
* jn: (libc)Special Functions.
* jnf: (libc)Special Functions.
* jnl: (libc)Special Functions.
* jrand48: (libc)SVID Random.
* jrand48_r: (libc)SVID Random.
* kill: (libc)Signaling Another Process.
* killpg: (libc)Signaling Another Process.
* l64a: (libc)Encode Binary Data.
* labs: (libc)Absolute Value.
* lcong48: (libc)SVID Random.
* lcong48_r: (libc)SVID Random.
* ldexp: (libc)Normalization Functions.
* ldexpf: (libc)Normalization Functions.
* ldexpl: (libc)Normalization Functions.
* ldiv: (libc)Integer Division.
* lfind: (libc)Array Search Function.
* lgamma: (libc)Special Functions.
* lgamma_r: (libc)Special Functions.
* lgammaf: (libc)Special Functions.
* lgammaf_r: (libc)Special Functions.
* lgammal: (libc)Special Functions.
* lgammal_r: (libc)Special Functions.
* link: (libc)Hard Links.
* lio_listio64: (libc)Asynchronous Reads/Writes.
* lio_listio: (libc)Asynchronous Reads/Writes.
* listen: (libc)Listening.
* llabs: (libc)Absolute Value.
* lldiv: (libc)Integer Division.
* llrint: (libc)Rounding Functions.
* llrintf: (libc)Rounding Functions.
* llrintl: (libc)Rounding Functions.
* llround: (libc)Rounding Functions.
* llroundf: (libc)Rounding Functions.
* llroundl: (libc)Rounding Functions.
* localeconv: (libc)The Lame Way to Locale Data.
* localtime: (libc)Broken-down Time.
* localtime_r: (libc)Broken-down Time.
* log10: (libc)Exponents and Logarithms.
* log10f: (libc)Exponents and Logarithms.
* log10l: (libc)Exponents and Logarithms.
* log1p: (libc)Exponents and Logarithms.
* log1pf: (libc)Exponents and Logarithms.
* log1pl: (libc)Exponents and Logarithms.
* log2: (libc)Exponents and Logarithms.
* log2f: (libc)Exponents and Logarithms.
* log2l: (libc)Exponents and Logarithms.
* log: (libc)Exponents and Logarithms.
* logb: (libc)Exponents and Logarithms.
* logbf: (libc)Exponents and Logarithms.
* logbl: (libc)Exponents and Logarithms.
* logf: (libc)Exponents and Logarithms.
* login: (libc)Logging In and Out.
* login_tty: (libc)Logging In and Out.
* logl: (libc)Exponents and Logarithms.
* logout: (libc)Logging In and Out.
* logwtmp: (libc)Logging In and Out.
* longjmp: (libc)Non-Local Details.
* lrand48: (libc)SVID Random.
* lrand48_r: (libc)SVID Random.
* lrint: (libc)Rounding Functions.
* lrintf: (libc)Rounding Functions.
* lrintl: (libc)Rounding Functions.
* lround: (libc)Rounding Functions.
* lroundf: (libc)Rounding Functions.
* lroundl: (libc)Rounding Functions.
* lsearch: (libc)Array Search Function.
* lseek64: (libc)File Position Primitive.
* lseek: (libc)File Position Primitive.
* lstat64: (libc)Reading Attributes.
* lstat: (libc)Reading Attributes.
* lutimes: (libc)File Times.
* madvise: (libc)Memory-mapped I/O.
* makecontext: (libc)System V contexts.
* mallinfo: (libc)Statistics of Malloc.
* malloc: (libc)Basic Allocation.
* mallopt: (libc)Malloc Tunable Parameters.
* mblen: (libc)Non-reentrant Character Conversion.
* mbrlen: (libc)Converting a Character.
* mbrtowc: (libc)Converting a Character.
* mbsinit: (libc)Keeping the state.
* mbsnrtowcs: (libc)Converting Strings.
* mbsrtowcs: (libc)Converting Strings.
* mbstowcs: (libc)Non-reentrant String Conversion.
* mbtowc: (libc)Non-reentrant Character Conversion.
* mcheck: (libc)Heap Consistency Checking.
* memalign: (libc)Aligned Memory Blocks.
* memccpy: (libc)Copying and Concatenation.
* memchr: (libc)Search Functions.
* memcmp: (libc)String/Array Comparison.
* memcpy: (libc)Copying and Concatenation.
* memfrob: (libc)Trivial Encryption.
* memmem: (libc)Search Functions.
* memmove: (libc)Copying and Concatenation.
* mempcpy: (libc)Copying and Concatenation.
* memrchr: (libc)Search Functions.
* memset: (libc)Copying and Concatenation.
* mkdir: (libc)Creating Directories.
* mkdtemp: (libc)Temporary Files.
* mkfifo: (libc)FIFO Special Files.
* mknod: (libc)Making Special Files.
* mkstemp: (libc)Temporary Files.
* mktemp: (libc)Temporary Files.
* mktime: (libc)Broken-down Time.
* mlock: (libc)Page Lock Functions.
* mlockall: (libc)Page Lock Functions.
* mmap64: (libc)Memory-mapped I/O.
* mmap: (libc)Memory-mapped I/O.
* modf: (libc)Rounding Functions.
* modff: (libc)Rounding Functions.
* modfl: (libc)Rounding Functions.
* mount: (libc)Mount-Unmount-Remount.
* mprobe: (libc)Heap Consistency Checking.
* mrand48: (libc)SVID Random.
* mrand48_r: (libc)SVID Random.
* mremap: (libc)Memory-mapped I/O.
* msync: (libc)Memory-mapped I/O.
* mtrace: (libc)Tracing malloc.
* munlock: (libc)Page Lock Functions.
* munlockall: (libc)Page Lock Functions.
* munmap: (libc)Memory-mapped I/O.
* muntrace: (libc)Tracing malloc.
* nan: (libc)FP Bit Twiddling.
* nanf: (libc)FP Bit Twiddling.
* nanl: (libc)FP Bit Twiddling.
* nanosleep: (libc)Sleeping.
* nearbyint: (libc)Rounding Functions.
* nearbyintf: (libc)Rounding Functions.
* nearbyintl: (libc)Rounding Functions.
* nextafter: (libc)FP Bit Twiddling.
* nextafterf: (libc)FP Bit Twiddling.
* nextafterl: (libc)FP Bit Twiddling.
* nexttoward: (libc)FP Bit Twiddling.
* nexttowardf: (libc)FP Bit Twiddling.
* nexttowardl: (libc)FP Bit Twiddling.
* nftw64: (libc)Working with Directory Trees.
* nftw: (libc)Working with Directory Trees.
* ngettext: (libc)Advanced gettext functions.
* nice: (libc)Traditional Scheduling Functions.
* nl_langinfo: (libc)The Elegant and Fast Way.
* nrand48: (libc)SVID Random.
* nrand48_r: (libc)SVID Random.
* ntohl: (libc)Byte Order.
* ntohs: (libc)Byte Order.
* ntp_adjtime: (libc)High Accuracy Clock.
* ntp_gettime: (libc)High Accuracy Clock.
* obstack_1grow: (libc)Growing Objects.
* obstack_1grow_fast: (libc)Extra Fast Growing.
* obstack_alignment_mask: (libc)Obstacks Data Alignment.
* obstack_alloc: (libc)Allocation in an Obstack.
* obstack_base: (libc)Status of an Obstack.
* obstack_blank: (libc)Growing Objects.
* obstack_blank_fast: (libc)Extra Fast Growing.
* obstack_chunk_size: (libc)Obstack Chunks.
* obstack_copy0: (libc)Allocation in an Obstack.
* obstack_copy: (libc)Allocation in an Obstack.
* obstack_finish: (libc)Growing Objects.
* obstack_free: (libc)Freeing Obstack Objects.
* obstack_grow0: (libc)Growing Objects.
* obstack_grow: (libc)Growing Objects.
* obstack_init: (libc)Preparing for Obstacks.
* obstack_int_grow: (libc)Growing Objects.
* obstack_int_grow_fast: (libc)Extra Fast Growing.
* obstack_next_free: (libc)Status of an Obstack.
* obstack_object_size: (libc)Growing Objects.
* obstack_object_size: (libc)Status of an Obstack.
* obstack_printf: (libc)Dynamic Output.
* obstack_ptr_grow: (libc)Growing Objects.
* obstack_ptr_grow_fast: (libc)Extra Fast Growing.
* obstack_room: (libc)Extra Fast Growing.
* obstack_vprintf: (libc)Variable Arguments Output.
* offsetof: (libc)Structure Measurement.
* on_exit: (libc)Cleanups on Exit.
* open64: (libc)Opening and Closing Files.
* open: (libc)Opening and Closing Files.
* open_memstream: (libc)String Streams.
* opendir: (libc)Opening a Directory.
* openlog: (libc)openlog.
* openpty: (libc)Pseudo-Terminal Pairs.
* parse_printf_format: (libc)Parsing a Template String.
* pathconf: (libc)Pathconf.
* pause: (libc)Using Pause.
* pclose: (libc)Pipe to a Subprocess.
* perror: (libc)Error Messages.
* pipe: (libc)Creating a Pipe.
* popen: (libc)Pipe to a Subprocess.
* posix_memalign: (libc)Aligned Memory Blocks.
* pow10: (libc)Exponents and Logarithms.
* pow10f: (libc)Exponents and Logarithms.
* pow10l: (libc)Exponents and Logarithms.
* pow: (libc)Exponents and Logarithms.
* powf: (libc)Exponents and Logarithms.
* powl: (libc)Exponents and Logarithms.
* pread64: (libc)I/O Primitives.
* pread: (libc)I/O Primitives.
* printf: (libc)Formatted Output Functions.
* printf_size: (libc)Predefined Printf Handlers.
* printf_size_info: (libc)Predefined Printf Handlers.
* psignal: (libc)Signal Messages.
* pthread_getattr_default_np: (libc)Default Thread Attributes.
* pthread_getattr_default_np: (libc)Default Thread Attributes.
* ptsname: (libc)Allocation.
* ptsname_r: (libc)Allocation.
* putc: (libc)Simple Output.
* putc_unlocked: (libc)Simple Output.
* putchar: (libc)Simple Output.
* putchar_unlocked: (libc)Simple Output.
* putenv: (libc)Environment Access.
* putpwent: (libc)Writing a User Entry.
* puts: (libc)Simple Output.
* pututline: (libc)Manipulating the Database.
* pututxline: (libc)XPG Functions.
* putw: (libc)Simple Output.
* putwc: (libc)Simple Output.
* putwc_unlocked: (libc)Simple Output.
* putwchar: (libc)Simple Output.
* putwchar_unlocked: (libc)Simple Output.
* pwrite64: (libc)I/O Primitives.
* pwrite: (libc)I/O Primitives.
* qecvt: (libc)System V Number Conversion.
* qecvt_r: (libc)System V Number Conversion.
* qfcvt: (libc)System V Number Conversion.
* qfcvt_r: (libc)System V Number Conversion.
* qgcvt: (libc)System V Number Conversion.
* qsort: (libc)Array Sort Function.
* raise: (libc)Signaling Yourself.
* rand: (libc)ISO Random.
* rand_r: (libc)ISO Random.
* random: (libc)BSD Random.
* random_r: (libc)BSD Random.
* rawmemchr: (libc)Search Functions.
* read: (libc)I/O Primitives.
* readdir64: (libc)Reading/Closing Directory.
* readdir64_r: (libc)Reading/Closing Directory.
* readdir: (libc)Reading/Closing Directory.
* readdir_r: (libc)Reading/Closing Directory.
* readlink: (libc)Symbolic Links.
* readv: (libc)Scatter-Gather.
* realloc: (libc)Changing Block Size.
* realpath: (libc)Symbolic Links.
* recv: (libc)Receiving Data.
* recvfrom: (libc)Receiving Datagrams.
* recvmsg: (libc)Receiving Datagrams.
* regcomp: (libc)POSIX Regexp Compilation.
* regerror: (libc)Regexp Cleanup.
* regexec: (libc)Matching POSIX Regexps.
* regfree: (libc)Regexp Cleanup.
* register_printf_function: (libc)Registering New Conversions.
* remainder: (libc)Remainder Functions.
* remainderf: (libc)Remainder Functions.
* remainderl: (libc)Remainder Functions.
* remove: (libc)Deleting Files.
* rename: (libc)Renaming Files.
* rewind: (libc)File Positioning.
* rewinddir: (libc)Random Access Directory.
* rindex: (libc)Search Functions.
* rint: (libc)Rounding Functions.
* rintf: (libc)Rounding Functions.
* rintl: (libc)Rounding Functions.
* rmdir: (libc)Deleting Files.
* round: (libc)Rounding Functions.
* roundf: (libc)Rounding Functions.
* roundl: (libc)Rounding Functions.
* rpmatch: (libc)Yes-or-No Questions.
* sbrk: (libc)Resizing the Data Segment.
* scalb: (libc)Normalization Functions.
* scalbf: (libc)Normalization Functions.
* scalbl: (libc)Normalization Functions.
* scalbln: (libc)Normalization Functions.
* scalblnf: (libc)Normalization Functions.
* scalblnl: (libc)Normalization Functions.
* scalbn: (libc)Normalization Functions.
* scalbnf: (libc)Normalization Functions.
* scalbnl: (libc)Normalization Functions.
* scandir64: (libc)Scanning Directory Content.
* scandir: (libc)Scanning Directory Content.
* scanf: (libc)Formatted Input Functions.
* sched_get_priority_max: (libc)Basic Scheduling Functions.
* sched_get_priority_min: (libc)Basic Scheduling Functions.
* sched_getaffinity: (libc)CPU Affinity.
* sched_getparam: (libc)Basic Scheduling Functions.
* sched_getscheduler: (libc)Basic Scheduling Functions.
* sched_rr_get_interval: (libc)Basic Scheduling Functions.
* sched_setaffinity: (libc)CPU Affinity.
* sched_setparam: (libc)Basic Scheduling Functions.
* sched_setscheduler: (libc)Basic Scheduling Functions.
* sched_yield: (libc)Basic Scheduling Functions.
* secure_getenv: (libc)Environment Access.
* seed48: (libc)SVID Random.
* seed48_r: (libc)SVID Random.
* seekdir: (libc)Random Access Directory.
* select: (libc)Waiting for I/O.
* send: (libc)Sending Data.
* sendmsg: (libc)Receiving Datagrams.
* sendto: (libc)Sending Datagrams.
* setbuf: (libc)Controlling Buffering.
* setbuffer: (libc)Controlling Buffering.
* setcontext: (libc)System V contexts.
* setdomainname: (libc)Host Identification.
* setegid: (libc)Setting Groups.
* setenv: (libc)Environment Access.
* seteuid: (libc)Setting User ID.
* setfsent: (libc)fstab.
* setgid: (libc)Setting Groups.
* setgrent: (libc)Scanning All Groups.
* setgroups: (libc)Setting Groups.
* sethostent: (libc)Host Names.
* sethostid: (libc)Host Identification.
* sethostname: (libc)Host Identification.
* setitimer: (libc)Setting an Alarm.
* setjmp: (libc)Non-Local Details.
* setkey: (libc)DES Encryption.
* setkey_r: (libc)DES Encryption.
* setlinebuf: (libc)Controlling Buffering.
* setlocale: (libc)Setting the Locale.
* setlogmask: (libc)setlogmask.
* setmntent: (libc)mtab.
* setnetent: (libc)Networks Database.
* setnetgrent: (libc)Lookup Netgroup.
* setpgid: (libc)Process Group Functions.
* setpgrp: (libc)Process Group Functions.
* setpriority: (libc)Traditional Scheduling Functions.
* setprotoent: (libc)Protocols Database.
* setpwent: (libc)Scanning All Users.
* setregid: (libc)Setting Groups.
* setreuid: (libc)Setting User ID.
* setrlimit64: (libc)Limits on Resources.
* setrlimit: (libc)Limits on Resources.
* setservent: (libc)Services Database.
* setsid: (libc)Process Group Functions.
* setsockopt: (libc)Socket Option Functions.
* setstate: (libc)BSD Random.
* setstate_r: (libc)BSD Random.
* settimeofday: (libc)High-Resolution Calendar.
* setuid: (libc)Setting User ID.
* setutent: (libc)Manipulating the Database.
* setutxent: (libc)XPG Functions.
* setvbuf: (libc)Controlling Buffering.
* shutdown: (libc)Closing a Socket.
* sigaction: (libc)Advanced Signal Handling.
* sigaddset: (libc)Signal Sets.
* sigaltstack: (libc)Signal Stack.
* sigblock: (libc)Blocking in BSD.
* sigdelset: (libc)Signal Sets.
* sigemptyset: (libc)Signal Sets.
* sigfillset: (libc)Signal Sets.
* siginterrupt: (libc)BSD Handler.
* sigismember: (libc)Signal Sets.
* siglongjmp: (libc)Non-Local Exits and Signals.
* sigmask: (libc)Blocking in BSD.
* signal: (libc)Basic Signal Handling.
* signbit: (libc)FP Bit Twiddling.
* significand: (libc)Normalization Functions.
* significandf: (libc)Normalization Functions.
* significandl: (libc)Normalization Functions.
* sigpause: (libc)Blocking in BSD.
* sigpending: (libc)Checking for Pending Signals.
* sigprocmask: (libc)Process Signal Mask.
* sigsetjmp: (libc)Non-Local Exits and Signals.
* sigsetmask: (libc)Blocking in BSD.
* sigstack: (libc)Signal Stack.
* sigsuspend: (libc)Sigsuspend.
* sigvec: (libc)BSD Handler.
* sin: (libc)Trig Functions.
* sincos: (libc)Trig Functions.
* sincosf: (libc)Trig Functions.
* sincosl: (libc)Trig Functions.
* sinf: (libc)Trig Functions.
* sinh: (libc)Hyperbolic Functions.
* sinhf: (libc)Hyperbolic Functions.
* sinhl: (libc)Hyperbolic Functions.
* sinl: (libc)Trig Functions.
* sleep: (libc)Sleeping.
* snprintf: (libc)Formatted Output Functions.
* socket: (libc)Creating a Socket.
* socketpair: (libc)Socket Pairs.
* sprintf: (libc)Formatted Output Functions.
* sqrt: (libc)Exponents and Logarithms.
* sqrtf: (libc)Exponents and Logarithms.
* sqrtl: (libc)Exponents and Logarithms.
* srand48: (libc)SVID Random.
* srand48_r: (libc)SVID Random.
* srand: (libc)ISO Random.
* srandom: (libc)BSD Random.
* srandom_r: (libc)BSD Random.
* sscanf: (libc)Formatted Input Functions.
* ssignal: (libc)Basic Signal Handling.
* stat64: (libc)Reading Attributes.
* stat: (libc)Reading Attributes.
* stime: (libc)Simple Calendar Time.
* stpcpy: (libc)Copying and Concatenation.
* stpncpy: (libc)Copying and Concatenation.
* strcasecmp: (libc)String/Array Comparison.
* strcasestr: (libc)Search Functions.
* strcat: (libc)Copying and Concatenation.
* strchr: (libc)Search Functions.
* strchrnul: (libc)Search Functions.
* strcmp: (libc)String/Array Comparison.
* strcoll: (libc)Collation Functions.
* strcpy: (libc)Copying and Concatenation.
* strcspn: (libc)Search Functions.
* strdup: (libc)Copying and Concatenation.
* strdupa: (libc)Copying and Concatenation.
* strerror: (libc)Error Messages.
* strerror_r: (libc)Error Messages.
* strfmon: (libc)Formatting Numbers.
* strfry: (libc)strfry.
* strftime: (libc)Formatting Calendar Time.
* strlen: (libc)String Length.
* strncasecmp: (libc)String/Array Comparison.
* strncat: (libc)Copying and Concatenation.
* strncmp: (libc)String/Array Comparison.
* strncpy: (libc)Copying and Concatenation.
* strndup: (libc)Copying and Concatenation.
* strndupa: (libc)Copying and Concatenation.
* strnlen: (libc)String Length.
* strpbrk: (libc)Search Functions.
* strptime: (libc)Low-Level Time String Parsing.
* strrchr: (libc)Search Functions.
* strsep: (libc)Finding Tokens in a String.
* strsignal: (libc)Signal Messages.
* strspn: (libc)Search Functions.
* strstr: (libc)Search Functions.
* strtod: (libc)Parsing of Floats.
* strtof: (libc)Parsing of Floats.
* strtoimax: (libc)Parsing of Integers.
* strtok: (libc)Finding Tokens in a String.
* strtok_r: (libc)Finding Tokens in a String.
* strtol: (libc)Parsing of Integers.
* strtold: (libc)Parsing of Floats.
* strtoll: (libc)Parsing of Integers.
* strtoq: (libc)Parsing of Integers.
* strtoul: (libc)Parsing of Integers.
* strtoull: (libc)Parsing of Integers.
* strtoumax: (libc)Parsing of Integers.
* strtouq: (libc)Parsing of Integers.
* strverscmp: (libc)String/Array Comparison.
* strxfrm: (libc)Collation Functions.
* stty: (libc)BSD Terminal Modes.
* swapcontext: (libc)System V contexts.
* swprintf: (libc)Formatted Output Functions.
* swscanf: (libc)Formatted Input Functions.
* symlink: (libc)Symbolic Links.
* sync: (libc)Synchronizing I/O.
* syscall: (libc)System Calls.
* sysconf: (libc)Sysconf Definition.
* sysctl: (libc)System Parameters.
* syslog: (libc)syslog; vsyslog.
* system: (libc)Running a Command.
* sysv_signal: (libc)Basic Signal Handling.
* tan: (libc)Trig Functions.
* tanf: (libc)Trig Functions.
* tanh: (libc)Hyperbolic Functions.
* tanhf: (libc)Hyperbolic Functions.
* tanhl: (libc)Hyperbolic Functions.
* tanl: (libc)Trig Functions.
* tcdrain: (libc)Line Control.
* tcflow: (libc)Line Control.
* tcflush: (libc)Line Control.
* tcgetattr: (libc)Mode Functions.
* tcgetpgrp: (libc)Terminal Access Functions.
* tcgetsid: (libc)Terminal Access Functions.
* tcsendbreak: (libc)Line Control.
* tcsetattr: (libc)Mode Functions.
* tcsetpgrp: (libc)Terminal Access Functions.
* tdelete: (libc)Tree Search Function.
* tdestroy: (libc)Tree Search Function.
* telldir: (libc)Random Access Directory.
* tempnam: (libc)Temporary Files.
* textdomain: (libc)Locating gettext catalog.
* tfind: (libc)Tree Search Function.
* tgamma: (libc)Special Functions.
* tgammaf: (libc)Special Functions.
* tgammal: (libc)Special Functions.
* time: (libc)Simple Calendar Time.
* timegm: (libc)Broken-down Time.
* timelocal: (libc)Broken-down Time.
* times: (libc)Processor Time.
* tmpfile64: (libc)Temporary Files.
* tmpfile: (libc)Temporary Files.
* tmpnam: (libc)Temporary Files.
* tmpnam_r: (libc)Temporary Files.
* toascii: (libc)Case Conversion.
* tolower: (libc)Case Conversion.
* toupper: (libc)Case Conversion.
* towctrans: (libc)Wide Character Case Conversion.
* towlower: (libc)Wide Character Case Conversion.
* towupper: (libc)Wide Character Case Conversion.
* trunc: (libc)Rounding Functions.
* truncate64: (libc)File Size.
* truncate: (libc)File Size.
* truncf: (libc)Rounding Functions.
* truncl: (libc)Rounding Functions.
* tsearch: (libc)Tree Search Function.
* ttyname: (libc)Is It a Terminal.
* ttyname_r: (libc)Is It a Terminal.
* twalk: (libc)Tree Search Function.
* tzset: (libc)Time Zone Functions.
* ulimit: (libc)Limits on Resources.
* umask: (libc)Setting Permissions.
* umount2: (libc)Mount-Unmount-Remount.
* umount: (libc)Mount-Unmount-Remount.
* uname: (libc)Platform Type.
* ungetc: (libc)How Unread.
* ungetwc: (libc)How Unread.
* unlink: (libc)Deleting Files.
* unlockpt: (libc)Allocation.
* unsetenv: (libc)Environment Access.
* updwtmp: (libc)Manipulating the Database.
* utime: (libc)File Times.
* utimes: (libc)File Times.
* utmpname: (libc)Manipulating the Database.
* utmpxname: (libc)XPG Functions.
* va_arg: (libc)Argument Macros.
* va_copy: (libc)Argument Macros.
* va_end: (libc)Argument Macros.
* va_start: (libc)Argument Macros.
* valloc: (libc)Aligned Memory Blocks.
* vasprintf: (libc)Variable Arguments Output.
* verr: (libc)Error Messages.
* verrx: (libc)Error Messages.
* versionsort64: (libc)Scanning Directory Content.
* versionsort: (libc)Scanning Directory Content.
* vfork: (libc)Creating a Process.
* vfprintf: (libc)Variable Arguments Output.
* vfscanf: (libc)Variable Arguments Input.
* vfwprintf: (libc)Variable Arguments Output.
* vfwscanf: (libc)Variable Arguments Input.
* vlimit: (libc)Limits on Resources.
* vprintf: (libc)Variable Arguments Output.
* vscanf: (libc)Variable Arguments Input.
* vsnprintf: (libc)Variable Arguments Output.
* vsprintf: (libc)Variable Arguments Output.
* vsscanf: (libc)Variable Arguments Input.
* vswprintf: (libc)Variable Arguments Output.
* vswscanf: (libc)Variable Arguments Input.
* vsyslog: (libc)syslog; vsyslog.
* vtimes: (libc)Resource Usage.
* vwarn: (libc)Error Messages.
* vwarnx: (libc)Error Messages.
* vwprintf: (libc)Variable Arguments Output.
* vwscanf: (libc)Variable Arguments Input.
* wait3: (libc)BSD Wait Functions.
* wait4: (libc)Process Completion.
* wait: (libc)Process Completion.
* waitpid: (libc)Process Completion.
* warn: (libc)Error Messages.
* warnx: (libc)Error Messages.
* wcpcpy: (libc)Copying and Concatenation.
* wcpncpy: (libc)Copying and Concatenation.
* wcrtomb: (libc)Converting a Character.
* wcscasecmp: (libc)String/Array Comparison.
* wcscat: (libc)Copying and Concatenation.
* wcschr: (libc)Search Functions.
* wcschrnul: (libc)Search Functions.
* wcscmp: (libc)String/Array Comparison.
* wcscoll: (libc)Collation Functions.
* wcscpy: (libc)Copying and Concatenation.
* wcscspn: (libc)Search Functions.
* wcsdup: (libc)Copying and Concatenation.
* wcsftime: (libc)Formatting Calendar Time.
* wcslen: (libc)String Length.
* wcsncasecmp: (libc)String/Array Comparison.
* wcsncat: (libc)Copying and Concatenation.
* wcsncmp: (libc)String/Array Comparison.
* wcsncpy: (libc)Copying and Concatenation.
* wcsnlen: (libc)String Length.
* wcsnrtombs: (libc)Converting Strings.
* wcspbrk: (libc)Search Functions.
* wcsrchr: (libc)Search Functions.
* wcsrtombs: (libc)Converting Strings.
* wcsspn: (libc)Search Functions.
* wcsstr: (libc)Search Functions.
* wcstod: (libc)Parsing of Floats.
* wcstof: (libc)Parsing of Floats.
* wcstoimax: (libc)Parsing of Integers.
* wcstok: (libc)Finding Tokens in a String.
* wcstol: (libc)Parsing of Integers.
* wcstold: (libc)Parsing of Floats.
* wcstoll: (libc)Parsing of Integers.
* wcstombs: (libc)Non-reentrant String Conversion.
* wcstoq: (libc)Parsing of Integers.
* wcstoul: (libc)Parsing of Integers.
* wcstoull: (libc)Parsing of Integers.
* wcstoumax: (libc)Parsing of Integers.
* wcstouq: (libc)Parsing of Integers.
* wcswcs: (libc)Search Functions.
* wcsxfrm: (libc)Collation Functions.
* wctob: (libc)Converting a Character.
* wctomb: (libc)Non-reentrant Character Conversion.
* wctrans: (libc)Wide Character Case Conversion.
* wctype: (libc)Classification of Wide Characters.
* wmemchr: (libc)Search Functions.
* wmemcmp: (libc)String/Array Comparison.
* wmemcpy: (libc)Copying and Concatenation.
* wmemmove: (libc)Copying and Concatenation.
* wmempcpy: (libc)Copying and Concatenation.
* wmemset: (libc)Copying and Concatenation.
* wordexp: (libc)Calling Wordexp.
* wordfree: (libc)Calling Wordexp.
* wprintf: (libc)Formatted Output Functions.
* write: (libc)I/O Primitives.
* writev: (libc)Scatter-Gather.
* wscanf: (libc)Formatted Input Functions.
* y0: (libc)Special Functions.
* y0f: (libc)Special Functions.
* y0l: (libc)Special Functions.
* y1: (libc)Special Functions.
* y1f: (libc)Special Functions.
* y1l: (libc)Special Functions.
* yn: (libc)Special Functions.
* ynf: (libc)Special Functions.
* ynl: (libc)Special Functions.
END-INFO-DIR-ENTRY
This file documents the GNU C Library.
This is `The GNU C Library Reference Manual', for version
2.18-2013.10 (EGLIBC).
Copyright (C) 1993-2013 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version
1.3 or any later version published by the Free Software Foundation;
with the Invariant Sections being "Free Software Needs Free
Documentation" and "GNU Lesser General Public License", the Front-Cover
texts being "A GNU Manual", and with the Back-Cover Texts as in (a)
below. A copy of the license is included in the section entitled "GNU
Free Documentation License".
(a) The FSF's Back-Cover Text is: "You have the freedom to copy and
modify this GNU manual. Buying copies from the FSF supports it in
developing GNU and promoting software freedom."

File: libc.info, Node: Charset conversion in gettext, Next: GUI program problems, Prev: Advanced gettext functions, Up: Message catalogs with gettext
8.2.1.4 How to specify the output character set `gettext' uses
..............................................................
`gettext' not only looks up a translation in a message catalog. It
also converts the translation on the fly to the desired output character
set. This is useful if the user is working in a different character set
than the translator who created the message catalog, because it avoids
distributing variants of message catalogs which differ only in the
character set.
The output character set is, by default, the value of `nl_langinfo
(CODESET)', which depends on the `LC_CTYPE' part of the current locale.
But programs which store strings in a locale independent way (e.g.
UTF-8) can request that `gettext' and related functions return the
translations in that encoding, by use of the `bind_textdomain_codeset'
function.
Note that the MSGID argument to `gettext' is not subject to
character set conversion. Also, when `gettext' does not find a
translation for MSGID, it returns MSGID unchanged - independently of
the current output character set. It is therefore recommended that all
MSGIDs be US-ASCII strings.
-- Function: char * bind_textdomain_codeset (const char *DOMAINNAME,
const char *CODESET)
The `bind_textdomain_codeset' function can be used to specify the
output character set for message catalogs for domain DOMAINNAME.
The CODESET argument must be a valid codeset name which can be used
for the `iconv_open' function, or a null pointer.
If the CODESET parameter is the null pointer,
`bind_textdomain_codeset' returns the currently selected codeset
for the domain with the name DOMAINNAME. It returns `NULL' if no
codeset has yet been selected.
The `bind_textdomain_codeset' function can be used several times.
If used multiple times with the same DOMAINNAME argument, the
later call overrides the settings made by the earlier one.
The `bind_textdomain_codeset' function returns a pointer to a
string containing the name of the selected codeset. The string is
allocated internally in the function and must not be changed by the
user. If the system went out of core during the execution of
`bind_textdomain_codeset', the return value is `NULL' and the
global variable ERRNO is set accordingly.

File: libc.info, Node: GUI program problems, Next: Using gettextized software, Prev: Charset conversion in gettext, Up: Message catalogs with gettext
8.2.1.5 How to use `gettext' in GUI programs
............................................
One place where the `gettext' functions, if used normally, have big
problems is within programs with graphical user interfaces (GUIs). The
problem is that many of the strings which have to be translated are very
short. They have to appear in pull-down menus which restricts the
length. But strings which are not containing entire sentences or at
least large fragments of a sentence may appear in more than one
situation in the program but might have different translations. This is
especially true for the one-word strings which are frequently used in
GUI programs.
As a consequence many people say that the `gettext' approach is
wrong and instead `catgets' should be used which indeed does not have
this problem. But there is a very simple and powerful method to handle
these kind of problems with the `gettext' functions.
As an example consider the following fictional situation. A GUI program
has a menu bar with the following entries:
+------------+------------+--------------------------------------+
| File | Printer | |
+------------+------------+--------------------------------------+
| Open | | Select |
| New | | Open |
+----------+ | Connect |
+----------+
To have the strings `File', `Printer', `Open', `New', `Select', and
`Connect' translated there has to be at some point in the code a call
to a function of the `gettext' family. But in two places the string
passed into the function would be `Open'. The translations might not
be the same and therefore we are in the dilemma described above.
One solution to this problem is to artificially enlengthen the
strings to make them unambiguous. But what would the program do if no
translation is available? The enlengthened string is not what should be
printed. So we should use a little bit modified version of the
functions.
To enlengthen the strings a uniform method should be used. E.g., in
the example above the strings could be chosen as
Menu|File
Menu|Printer
Menu|File|Open
Menu|File|New
Menu|Printer|Select
Menu|Printer|Open
Menu|Printer|Connect
Now all the strings are different and if now instead of `gettext'
the following little wrapper function is used, everything works just
fine:
char *
sgettext (const char *msgid)
{
char *msgval = gettext (msgid);
if (msgval == msgid)
msgval = strrchr (msgid, '|') + 1;
return msgval;
}
What this little function does is to recognize the case when no
translation is available. This can be done very efficiently by a
pointer comparison since the return value is the input value. If there
is no translation we know that the input string is in the format we used
for the Menu entries and therefore contains a `|' character. We simply
search for the last occurrence of this character and return a pointer
to the character following it. That's it!
If one now consistently uses the enlengthened string form and
replaces the `gettext' calls with calls to `sgettext' (this is normally
limited to very few places in the GUI implementation) then it is
possible to produce a program which can be internationalized.
With advanced compilers (such as GNU C) one can write the `sgettext'
functions as an inline function or as a macro like this:
#define sgettext(msgid) \
({ const char *__msgid = (msgid); \
char *__msgstr = gettext (__msgid); \
if (__msgval == __msgid) \
__msgval = strrchr (__msgid, '|') + 1; \
__msgval; })
The other `gettext' functions (`dgettext', `dcgettext' and the
`ngettext' equivalents) can and should have corresponding functions as
well which look almost identical, except for the parameters and the
call to the underlying function.
Now there is of course the question why such functions do not exist
in the GNU C Library? There are two parts of the answer to this
question.
* They are easy to write and therefore can be provided by the
project they are used in. This is not an answer by itself and
must be seen together with the second part which is:
* There is no way the C library can contain a version which can work
everywhere. The problem is the selection of the character to
separate the prefix from the actual string in the enlenghtened
string. The examples above used `|' which is a quite good choice
because it resembles a notation frequently used in this context
and it also is a character not often used in message strings.
But what if the character is used in message strings. Or if the
chose character is not available in the character set on the
machine one compiles (e.g., `|' is not required to exist for
ISO C; this is why the `iso646.h' file exists in ISO C programming
environments).
There is only one more comment to make left. The wrapper function
above require that the translations strings are not enlengthened
themselves. This is only logical. There is no need to disambiguate
the strings (since they are never used as keys for a search) and one
also saves quite some memory and disk space by doing this.

File: libc.info, Node: Using gettextized software, Prev: GUI program problems, Up: Message catalogs with gettext
8.2.1.6 User influence on `gettext'
...................................
The last sections described what the programmer can do to
internationalize the messages of the program. But it is finally up to
the user to select the message s/he wants to see. S/He must understand
them.
The POSIX locale model uses the environment variables `LC_COLLATE',
`LC_CTYPE', `LC_MESSAGES', `LC_MONETARY', `LC_NUMERIC', and `LC_TIME'
to select the locale which is to be used. This way the user can
influence lots of functions. As we mentioned above the `gettext'
functions also take advantage of this.
To understand how this happens it is necessary to take a look at the
various components of the filename which gets computed to locate a
message catalog. It is composed as follows:
DIR_NAME/LOCALE/LC_CATEGORY/DOMAIN_NAME.mo
The default value for DIR_NAME is system specific. It is computed
from the value given as the prefix while configuring the C library.
This value normally is `/usr' or `/'. For the former the complete
DIR_NAME is:
/usr/share/locale
We can use `/usr/share' since the `.mo' files containing the message
catalogs are system independent, so all systems can use the same files.
If the program executed the `bindtextdomain' function for the message
domain that is currently handled, the `dir_name' component is exactly
the value which was given to the function as the second parameter.
I.e., `bindtextdomain' allows overwriting the only system dependent and
fixed value to make it possible to address files anywhere in the
filesystem.
The CATEGORY is the name of the locale category which was selected
in the program code. For `gettext' and `dgettext' this is always
`LC_MESSAGES', for `dcgettext' this is selected by the value of the
third parameter. As said above it should be avoided to ever use a
category other than `LC_MESSAGES'.
The LOCALE component is computed based on the category used. Just
like for the `setlocale' function here comes the user selection into
the play. Some environment variables are examined in a fixed order and
the first environment variable set determines the return value of the
lookup process. In detail, for the category `LC_xxx' the following
variables in this order are examined:
`LANGUAGE'
`LC_ALL'
`LC_xxx'
`LANG'
This looks very familiar. With the exception of the `LANGUAGE'
environment variable this is exactly the lookup order the `setlocale'
function uses. But why introducing the `LANGUAGE' variable?
The reason is that the syntax of the values these variables can have
is different to what is expected by the `setlocale' function. If we
would set `LC_ALL' to a value following the extended syntax that would
mean the `setlocale' function will never be able to use the value of
this variable as well. An additional variable removes this problem
plus we can select the language independently of the locale setting
which sometimes is useful.
While for the `LC_xxx' variables the value should consist of exactly
one specification of a locale the `LANGUAGE' variable's value can
consist of a colon separated list of locale names. The attentive
reader will realize that this is the way we manage to implement one of
our additional demands above: we want to be able to specify an ordered
list of language.
Back to the constructed filename we have only one component missing.
The DOMAIN_NAME part is the name which was either registered using the
`textdomain' function or which was given to `dgettext' or `dcgettext'
as the first parameter. Now it becomes obvious that a good choice for
the domain name in the program code is a string which is closely
related to the program/package name. E.g., for the GNU C Library the
domain name is `libc'.
A limit piece of example code should show how the programmer is supposed
to work:
{
setlocale (LC_ALL, "");
textdomain ("test-package");
bindtextdomain ("test-package", "/usr/local/share/locale");
puts (gettext ("Hello, world!"));
}
At the program start the default domain is `messages', and the
default locale is "C". The `setlocale' call sets the locale according
to the user's environment variables; remember that correct functioning
of `gettext' relies on the correct setting of the `LC_MESSAGES' locale
(for looking up the message catalog) and of the `LC_CTYPE' locale (for
the character set conversion). The `textdomain' call changes the
default domain to `test-package'. The `bindtextdomain' call specifies
that the message catalogs for the domain `test-package' can be found
below the directory `/usr/local/share/locale'.
If now the user set in her/his environment the variable `LANGUAGE'
to `de' the `gettext' function will try to use the translations from
the file
/usr/local/share/locale/de/LC_MESSAGES/test-package.mo
From the above descriptions it should be clear which component of
this filename is determined by which source.
In the above example we assumed that the `LANGUAGE' environment
variable to `de'. This might be an appropriate selection but what
happens if the user wants to use `LC_ALL' because of the wider
usability and here the required value is `de_DE.ISO-8859-1'? We
already mentioned above that a situation like this is not infrequent.
E.g., a person might prefer reading a dialect and if this is not
available fall back on the standard language.
The `gettext' functions know about situations like this and can
handle them gracefully. The functions recognize the format of the value
of the environment variable. It can split the value is different pieces
and by leaving out the only or the other part it can construct new
values. This happens of course in a predictable way. To understand
this one must know the format of the environment variable value. There
is one more or less standardized form, originally from the X/Open
specification:
`language[_territory[.codeset]][@modifier]'
Less specific locale names will be stripped of in the order of the
following list:
1. `codeset'
2. `normalized codeset'
3. `territory'
4. `modifier'
The `language' field will never be dropped for obvious reasons.
The only new thing is the `normalized codeset' entry. This is
another goodie which is introduced to help reducing the chaos which
derives from the inability of the people to standardize the names of
character sets. Instead of ISO-8859-1 one can often see 8859-1, 88591,
iso8859-1, or iso_8859-1. The `normalized codeset' value is generated
from the user-provided character set name by applying the following
rules:
1. Remove all characters beside numbers and letters.
2. Fold letters to lowercase.
3. If the same only contains digits prepend the string `"iso"'.
So all of the above name will be normalized to `iso88591'. This allows
the program user much more freely choosing the locale name.
Even this extended functionality still does not help to solve the
problem that completely different names can be used to denote the same
locale (e.g., `de' and `german'). To be of help in this situation the
locale implementation and also the `gettext' functions know about
aliases.
The file `/usr/share/locale/locale.alias' (replace `/usr' with
whatever prefix you used for configuring the C library) contains a
mapping of alternative names to more regular names. The system manager
is free to add new entries to fill her/his own needs. The selected
locale from the environment is compared with the entries in the first
column of this file ignoring the case. If they match the value of the
second column is used instead for the further handling.
In the description of the format of the environment variables we
already mentioned the character set as a factor in the selection of the
message catalog. In fact, only catalogs which contain text written
using the character set of the system/program can be used (directly;
there will come a solution for this some day). This means for the user
that s/he will always have to take care for this. If in the collection
of the message catalogs there are files for the same language but coded
using different character sets the user has to be careful.

File: libc.info, Node: Helper programs for gettext, Prev: Message catalogs with gettext, Up: The Uniforum approach
8.2.2 Programs to handle message catalogs for `gettext'
-------------------------------------------------------
The GNU C Library does not contain the source code for the programs to
handle message catalogs for the `gettext' functions. As part of the
GNU project the GNU gettext package contains everything the developer
needs. The functionality provided by the tools in this package by far
exceeds the abilities of the `gencat' program described above for the
`catgets' functions.
There is a program `msgfmt' which is the equivalent program to the
`gencat' program. It generates from the human-readable and -editable
form of the message catalog a binary file which can be used by the
`gettext' functions. But there are several more programs available.
The `xgettext' program can be used to automatically extract the
translatable messages from a source file. I.e., the programmer need not
take care of the translations and the list of messages which have to be
translated. S/He will simply wrap the translatable string in calls to
`gettext' et.al and the rest will be done by `xgettext'. This program
has a lot of options which help to customize the output or help to
understand the input better.
Other programs help to manage the development cycle when new
messages appear in the source files or when a new translation of the
messages appears. Here it should only be noted that using all the
tools in GNU gettext it is possible to _completely_ automate the
handling of message catalogs. Beside marking the translatable strings
in the source code and generating the translations the developers do
not have anything to do themselves.

File: libc.info, Node: Searching and Sorting, Next: Pattern Matching, Prev: Message Translation, Up: Top
9 Searching and Sorting
***********************
This chapter describes functions for searching and sorting arrays of
arbitrary objects. You pass the appropriate comparison function to be
applied as an argument, along with the size of the objects in the array
and the total number of elements.
* Menu:
* Comparison Functions:: Defining how to compare two objects.
Since the sort and search facilities
are general, you have to specify the
ordering.
* Array Search Function:: The `bsearch' function.
* Array Sort Function:: The `qsort' function.
* Search/Sort Example:: An example program.
* Hash Search Function:: The `hsearch' function.
* Tree Search Function:: The `tsearch' function.

File: libc.info, Node: Comparison Functions, Next: Array Search Function, Up: Searching and Sorting
9.1 Defining the Comparison Function
====================================
In order to use the sorted array library functions, you have to describe
how to compare the elements of the array.
To do this, you supply a comparison function to compare two elements
of the array. The library will call this function, passing as arguments
pointers to two array elements to be compared. Your comparison function
should return a value the way `strcmp' (*note String/Array
Comparison::) does: negative if the first argument is "less" than the
second, zero if they are "equal", and positive if the first argument is
"greater".
Here is an example of a comparison function which works with an
array of numbers of type `double':
int
compare_doubles (const void *a, const void *b)
{
const double *da = (const double *) a;
const double *db = (const double *) b;
return (*da > *db) - (*da < *db);
}
The header file `stdlib.h' defines a name for the data type of
comparison functions. This type is a GNU extension.
int comparison_fn_t (const void *, const void *);

File: libc.info, Node: Array Search Function, Next: Array Sort Function, Prev: Comparison Functions, Up: Searching and Sorting
9.2 Array Search Function
=========================
Generally searching for a specific element in an array means that
potentially all elements must be checked. The GNU C Library contains
functions to perform linear search. The prototypes for the following
two functions can be found in `search.h'.
-- Function: void * lfind (const void *KEY, const void *BASE, size_t
*NMEMB, size_t SIZE, comparison_fn_t COMPAR)
The `lfind' function searches in the array with `*NMEMB' elements
of SIZE bytes pointed to by BASE for an element which matches the
one pointed to by KEY. The function pointed to by COMPAR is used
decide whether two elements match.
The return value is a pointer to the matching element in the array
starting at BASE if it is found. If no matching element is
available `NULL' is returned.
The mean runtime of this function is `*NMEMB'/2. This function
should only be used if elements often get added to or deleted from
the array in which case it might not be useful to sort the array
before searching.
-- Function: void * lsearch (const void *KEY, void *BASE, size_t
*NMEMB, size_t SIZE, comparison_fn_t COMPAR)
The `lsearch' function is similar to the `lfind' function. It
searches the given array for an element and returns it if found.
The difference is that if no matching element is found the
`lsearch' function adds the object pointed to by KEY (with a size
of SIZE bytes) at the end of the array and it increments the value
of `*NMEMB' to reflect this addition.
This means for the caller that if it is not sure that the array
contains the element one is searching for the memory allocated for
the array starting at BASE must have room for at least SIZE more
bytes. If one is sure the element is in the array it is better to
use `lfind' so having more room in the array is always necessary
when calling `lsearch'.
To search a sorted array for an element matching the key, use the
`bsearch' function. The prototype for this function is in the header
file `stdlib.h'.
-- Function: void * bsearch (const void *KEY, const void *ARRAY,
size_t COUNT, size_t SIZE, comparison_fn_t COMPARE)
The `bsearch' function searches the sorted array ARRAY for an
object that is equivalent to KEY. The array contains COUNT
elements, each of which is of size SIZE bytes.
The COMPARE function is used to perform the comparison. This
function is called with two pointer arguments and should return an
integer less than, equal to, or greater than zero corresponding to
whether its first argument is considered less than, equal to, or
greater than its second argument. The elements of the ARRAY must
already be sorted in ascending order according to this comparison
function.
The return value is a pointer to the matching array element, or a
null pointer if no match is found. If the array contains more
than one element that matches, the one that is returned is
unspecified.
This function derives its name from the fact that it is implemented
using the binary search algorithm.

File: libc.info, Node: Array Sort Function, Next: Search/Sort Example, Prev: Array Search Function, Up: Searching and Sorting
9.3 Array Sort Function
=======================
To sort an array using an arbitrary comparison function, use the
`qsort' function. The prototype for this function is in `stdlib.h'.
-- Function: void qsort (void *ARRAY, size_t COUNT, size_t SIZE,
comparison_fn_t COMPARE)
The QSORT function sorts the array ARRAY. The array contains
COUNT elements, each of which is of size SIZE.
The COMPARE function is used to perform the comparison on the
array elements. This function is called with two pointer
arguments and should return an integer less than, equal to, or
greater than zero corresponding to whether its first argument is
considered less than, equal to, or greater than its second
argument.
*Warning:* If two objects compare as equal, their order after
sorting is unpredictable. That is to say, the sorting is not
stable. This can make a difference when the comparison considers
only part of the elements. Two elements with the same sort key
may differ in other respects.
If you want the effect of a stable sort, you can get this result by
writing the comparison function so that, lacking other reason
distinguish between two elements, it compares them by their
addresses. Note that doing this may make the sorting algorithm
less efficient, so do it only if necessary.
Here is a simple example of sorting an array of doubles in
numerical order, using the comparison function defined above
(*note Comparison Functions::):
{
double *array;
int size;
...
qsort (array, size, sizeof (double), compare_doubles);
}
The `qsort' function derives its name from the fact that it was
originally implemented using the "quick sort" algorithm.
The implementation of `qsort' in this library might not be an
in-place sort and might thereby use an extra amount of memory to
store the array.

File: libc.info, Node: Search/Sort Example, Next: Hash Search Function, Prev: Array Sort Function, Up: Searching and Sorting
9.4 Searching and Sorting Example
=================================
Here is an example showing the use of `qsort' and `bsearch' with an
array of structures. The objects in the array are sorted by comparing
their `name' fields with the `strcmp' function. Then, we can look up
individual objects based on their names.
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
/* Define an array of critters to sort. */
struct critter
{
const char *name;
const char *species;
};
struct critter muppets[] =
{
{"Kermit", "frog"},
{"Piggy", "pig"},
{"Gonzo", "whatever"},
{"Fozzie", "bear"},
{"Sam", "eagle"},
{"Robin", "frog"},
{"Animal", "animal"},
{"Camilla", "chicken"},
{"Sweetums", "monster"},
{"Dr. Strangepork", "pig"},
{"Link Hogthrob", "pig"},
{"Zoot", "human"},
{"Dr. Bunsen Honeydew", "human"},
{"Beaker", "human"},
{"Swedish Chef", "human"}
};
int count = sizeof (muppets) / sizeof (struct critter);
/* This is the comparison function used for sorting and searching. */
int
critter_cmp (const void *v1, const void *v2)
{
const struct critter *c1 = v1;
const struct critter *c2 = v2;
return strcmp (c1->name, c2->name);
}
/* Print information about a critter. */
void
print_critter (const struct critter *c)
{
printf ("%s, the %s\n", c->name, c->species);
}
/* Do the lookup into the sorted array. */
void
find_critter (const char *name)
{
struct critter target, *result;
target.name = name;
result = bsearch (&target, muppets, count, sizeof (struct critter),
critter_cmp);
if (result)
print_critter (result);
else
printf ("Couldn't find %s.\n", name);
}
/* Main program. */
int
main (void)
{
int i;
for (i = 0; i < count; i++)
print_critter (&muppets[i]);
printf ("\n");
qsort (muppets, count, sizeof (struct critter), critter_cmp);
for (i = 0; i < count; i++)
print_critter (&muppets[i]);
printf ("\n");
find_critter ("Kermit");
find_critter ("Gonzo");
find_critter ("Janice");
return 0;
}
The output from this program looks like:
Kermit, the frog
Piggy, the pig
Gonzo, the whatever
Fozzie, the bear
Sam, the eagle
Robin, the frog
Animal, the animal
Camilla, the chicken
Sweetums, the monster
Dr. Strangepork, the pig
Link Hogthrob, the pig
Zoot, the human
Dr. Bunsen Honeydew, the human
Beaker, the human
Swedish Chef, the human
Animal, the animal
Beaker, the human
Camilla, the chicken
Dr. Bunsen Honeydew, the human
Dr. Strangepork, the pig
Fozzie, the bear
Gonzo, the whatever
Kermit, the frog
Link Hogthrob, the pig
Piggy, the pig
Robin, the frog
Sam, the eagle
Swedish Chef, the human
Sweetums, the monster
Zoot, the human
Kermit, the frog
Gonzo, the whatever
Couldn't find Janice.

File: libc.info, Node: Hash Search Function, Next: Tree Search Function, Prev: Search/Sort Example, Up: Searching and Sorting
9.5 The `hsearch' function.
===========================
The functions mentioned so far in this chapter are for searching in a
sorted or unsorted array. There are other methods to organize
information which later should be searched. The costs of insert,
delete and search differ. One possible implementation is using hashing
tables. The following functions are declared in the header file
`search.h'.
-- Function: int hcreate (size_t NEL)
The `hcreate' function creates a hashing table which can contain at
least NEL elements. There is no possibility to grow this table so
it is necessary to choose the value for NEL wisely. The method
used to implement this function might make it necessary to make the
number of elements in the hashing table larger than the expected
maximal number of elements. Hashing tables usually work
inefficiently if they are filled 80% or more. The constant access
time guaranteed by hashing can only be achieved if few collisions
exist. See Knuth's "The Art of Computer Programming, Part 3:
Searching and Sorting" for more information.
The weakest aspect of this function is that there can be at most
one hashing table used through the whole program. The table is
allocated in local memory out of control of the programmer. As an
extension the GNU C Library provides an additional set of
functions with an reentrant interface which provide a similar
interface but which allow to keep arbitrarily many hashing tables.
It is possible to use more than one hashing table in the program
run if the former table is first destroyed by a call to `hdestroy'.
The function returns a non-zero value if successful. If it return
zero something went wrong. This could either mean there is
already a hashing table in use or the program runs out of memory.
-- Function: void hdestroy (void)
The `hdestroy' function can be used to free all the resources
allocated in a previous call of `hcreate'. After a call to this
function it is again possible to call `hcreate' and allocate a new
table with possibly different size.
It is important to remember that the elements contained in the
hashing table at the time `hdestroy' is called are _not_ freed by
this function. It is the responsibility of the program code to
free those strings (if necessary at all). Freeing all the element
memory is not possible without extra, separately kept information
since there is no function to iterate through all available
elements in the hashing table. If it is really necessary to free
a table and all elements the programmer has to keep a list of all
table elements and before calling `hdestroy' s/he has to free all
element's data using this list. This is a very unpleasant
mechanism and it also shows that this kind of hashing tables is
mainly meant for tables which are created once and used until the
end of the program run.
Entries of the hashing table and keys for the search are defined
using this type:
-- Data type: struct ENTRY
Both elements of this structure are pointers to zero-terminated
strings. This is a limiting restriction of the functionality of
the `hsearch' functions. They can only be used for data sets
which use the NUL character always and solely to terminate the
records. It is not possible to handle general binary data.
`char *key'
Pointer to a zero-terminated string of characters describing
the key for the search or the element in the hashing table.
`char *data'
Pointer to a zero-terminated string of characters describing
the data. If the functions will be called only for searching
an existing entry this element might stay undefined since it
is not used.
-- Function: ENTRY * hsearch (ENTRY ITEM, ACTION ACTION)
To search in a hashing table created using `hcreate' the `hsearch'
function must be used. This function can perform simple search
for an element (if ACTION has the `FIND') or it can alternatively
insert the key element into the hashing table. Entries are never
replaced.
The key is denoted by a pointer to an object of type `ENTRY'. For
locating the corresponding position in the hashing table only the
`key' element of the structure is used.
If an entry with matching key is found the ACTION parameter is
irrelevant. The found entry is returned. If no matching entry is
found and the ACTION parameter has the value `FIND' the function
returns a `NULL' pointer. If no entry is found and the ACTION
parameter has the value `ENTER' a new entry is added to the
hashing table which is initialized with the parameter ITEM. A
pointer to the newly added entry is returned.
As mentioned before the hashing table used by the functions
described so far is global and there can be at any time at most one
hashing table in the program. A solution is to use the following
functions which are a GNU extension. All have in common that they
operate on a hashing table which is described by the content of an
object of the type `struct hsearch_data'. This type should be treated
as opaque, none of its members should be changed directly.
-- Function: int hcreate_r (size_t NEL, struct hsearch_data *HTAB)
The `hcreate_r' function initializes the object pointed to by HTAB
to contain a hashing table with at least NEL elements. So this
function is equivalent to the `hcreate' function except that the
initialized data structure is controlled by the user.
This allows having more than one hashing table at one time. The
memory necessary for the `struct hsearch_data' object can be
allocated dynamically. It must be initialized with zero before
calling this function.
The return value is non-zero if the operation was successful. If
the return value is zero, something went wrong, which probably
means the programs ran out of memory.
-- Function: void hdestroy_r (struct hsearch_data *HTAB)
The `hdestroy_r' function frees all resources allocated by the
`hcreate_r' function for this very same object HTAB. As for
`hdestroy' it is the programs responsibility to free the strings
for the elements of the table.
-- Function: int hsearch_r (ENTRY ITEM, ACTION ACTION, ENTRY **RETVAL,
struct hsearch_data *HTAB)
The `hsearch_r' function is equivalent to `hsearch'. The meaning
of the first two arguments is identical. But instead of operating
on a single global hashing table the function works on the table
described by the object pointed to by HTAB (which is initialized
by a call to `hcreate_r').
Another difference to `hcreate' is that the pointer to the found
entry in the table is not the return value of the functions. It is
returned by storing it in a pointer variables pointed to by the
RETVAL parameter. The return value of the function is an integer
value indicating success if it is non-zero and failure if it is
zero. In the latter case the global variable ERRNO signals the
reason for the failure.
`ENOMEM'
The table is filled and `hsearch_r' was called with an so far
unknown key and ACTION set to `ENTER'.
`ESRCH'
The ACTION parameter is `FIND' and no corresponding element
is found in the table.

File: libc.info, Node: Tree Search Function, Prev: Hash Search Function, Up: Searching and Sorting
9.6 The `tsearch' function.
===========================
Another common form to organize data for efficient search is to use
trees. The `tsearch' function family provides a nice interface to
functions to organize possibly large amounts of data by providing a mean
access time proportional to the logarithm of the number of elements.
The GNU C Library implementation even guarantees that this bound is
never exceeded even for input data which cause problems for simple
binary tree implementations.
The functions described in the chapter are all described in the
System V and X/Open specifications and are therefore quite portable.
In contrast to the `hsearch' functions the `tsearch' functions can
be used with arbitrary data and not only zero-terminated strings.
The `tsearch' functions have the advantage that no function to
initialize data structures is necessary. A simple pointer of type
`void *' initialized to `NULL' is a valid tree and can be extended or
searched. The prototypes for these functions can be found in the
header file `search.h'.
-- Function: void * tsearch (const void *KEY, void **ROOTP,
comparison_fn_t COMPAR)
The `tsearch' function searches in the tree pointed to by `*ROOTP'
for an element matching KEY. The function pointed to by COMPAR is
used to determine whether two elements match. *Note Comparison
Functions::, for a specification of the functions which can be
used for the COMPAR parameter.
If the tree does not contain a matching entry the KEY value will
be added to the tree. `tsearch' does not make a copy of the object
pointed to by KEY (how could it since the size is unknown).
Instead it adds a reference to this object which means the object
must be available as long as the tree data structure is used.
The tree is represented by a pointer to a pointer since it is
sometimes necessary to change the root node of the tree. So it
must not be assumed that the variable pointed to by ROOTP has the
same value after the call. This also shows that it is not safe to
call the `tsearch' function more than once at the same time using
the same tree. It is no problem to run it more than once at a
time on different trees.
The return value is a pointer to the matching element in the tree.
If a new element was created the pointer points to the new data
(which is in fact KEY). If an entry had to be created and the
program ran out of space `NULL' is returned.
-- Function: void * tfind (const void *KEY, void *const *ROOTP,
comparison_fn_t COMPAR)
The `tfind' function is similar to the `tsearch' function. It
locates an element matching the one pointed to by KEY and returns
a pointer to this element. But if no matching element is
available no new element is entered (note that the ROOTP parameter
points to a constant pointer). Instead the function returns
`NULL'.
Another advantage of the `tsearch' function in contrast to the
`hsearch' functions is that there is an easy way to remove elements.
-- Function: void * tdelete (const void *KEY, void **ROOTP,
comparison_fn_t COMPAR)
To remove a specific element matching KEY from the tree `tdelete'
can be used. It locates the matching element using the same
method as `tfind'. The corresponding element is then removed and
a pointer to the parent of the deleted node is returned by the
function. If there is no matching entry in the tree nothing can be
deleted and the function returns `NULL'. If the root of the tree
is deleted `tdelete' returns some unspecified value not equal to
`NULL'.
-- Function: void tdestroy (void *VROOT, __free_fn_t FREEFCT)
If the complete search tree has to be removed one can use
`tdestroy'. It frees all resources allocated by the `tsearch'
function to generate the tree pointed to by VROOT.
For the data in each tree node the function FREEFCT is called.
The pointer to the data is passed as the argument to the function.
If no such work is necessary FREEFCT must point to a function doing
nothing. It is called in any case.
This function is a GNU extension and not covered by the System V or
X/Open specifications.
In addition to the function to create and destroy the tree data
structure, there is another function which allows you to apply a
function to all elements of the tree. The function must have this type:
void __action_fn_t (const void *nodep, VISIT value, int level);
The NODEP is the data value of the current node (once given as the
KEY argument to `tsearch'). LEVEL is a numeric value which corresponds
to the depth of the current node in the tree. The root node has the
depth 0 and its children have a depth of 1 and so on. The `VISIT' type
is an enumeration type.
-- Data Type: VISIT
The `VISIT' value indicates the status of the current node in the
tree and how the function is called. The status of a node is
either `leaf' or `internal node'. For each leaf node the function
is called exactly once, for each internal node it is called three
times: before the first child is processed, after the first child
is processed and after both children are processed. This makes it
possible to handle all three methods of tree traversal (or even a
combination of them).
`preorder'
The current node is an internal node and the function is
called before the first child was processed.
`postorder'
The current node is an internal node and the function is
called after the first child was processed.
`endorder'
The current node is an internal node and the function is
called after the second child was processed.
`leaf'
The current node is a leaf.
-- Function: void twalk (const void *ROOT, __action_fn_t ACTION)
For each node in the tree with a node pointed to by ROOT, the
`twalk' function calls the function provided by the parameter
ACTION. For leaf nodes the function is called exactly once with
VALUE set to `leaf'. For internal nodes the function is called
three times, setting the VALUE parameter or ACTION to the
appropriate value. The LEVEL argument for the ACTION function is
computed while descending the tree with increasing the value by
one for the descend to a child, starting with the value 0 for the
root node.
Since the functions used for the ACTION parameter to `twalk' must
not modify the tree data, it is safe to run `twalk' in more than
one thread at the same time, working on the same tree. It is also
safe to call `tfind' in parallel. Functions which modify the tree
must not be used, otherwise the behavior is undefined.

File: libc.info, Node: Pattern Matching, Next: I/O Overview, Prev: Searching and Sorting, Up: Top
10 Pattern Matching
*******************
The GNU C Library provides pattern matching facilities for two kinds of
patterns: regular expressions and file-name wildcards. The library also
provides a facility for expanding variable and command references and
parsing text into words in the way the shell does.
* Menu:
* Wildcard Matching:: Matching a wildcard pattern against a single string.
* Globbing:: Finding the files that match a wildcard pattern.
* Regular Expressions:: Matching regular expressions against strings.
* Word Expansion:: Expanding shell variables, nested commands,
arithmetic, and wildcards.
This is what the shell does with shell commands.

File: libc.info, Node: Wildcard Matching, Next: Globbing, Up: Pattern Matching
10.1 Wildcard Matching
======================
This section describes how to match a wildcard pattern against a
particular string. The result is a yes or no answer: does the string
fit the pattern or not. The symbols described here are all declared in
`fnmatch.h'.
-- Function: int fnmatch (const char *PATTERN, const char *STRING, int
FLAGS)
This function tests whether the string STRING matches the pattern
PATTERN. It returns `0' if they do match; otherwise, it returns
the nonzero value `FNM_NOMATCH'. The arguments PATTERN and STRING
are both strings.
The argument FLAGS is a combination of flag bits that alter the
details of matching. See below for a list of the defined flags.
In the GNU C Library, `fnmatch' cannot experience an "error"--it
always returns an answer for whether the match succeeds. However,
other implementations of `fnmatch' might sometimes report "errors".
They would do so by returning nonzero values that are not equal to
`FNM_NOMATCH'.
These are the available flags for the FLAGS argument:
`FNM_FILE_NAME'
Treat the `/' character specially, for matching file names. If
this flag is set, wildcard constructs in PATTERN cannot match `/'
in STRING. Thus, the only way to match `/' is with an explicit
`/' in PATTERN.
`FNM_PATHNAME'
This is an alias for `FNM_FILE_NAME'; it comes from POSIX.2. We
don't recommend this name because we don't use the term "pathname"
for file names.
`FNM_PERIOD'
Treat the `.' character specially if it appears at the beginning of
STRING. If this flag is set, wildcard constructs in PATTERN
cannot match `.' as the first character of STRING.
If you set both `FNM_PERIOD' and `FNM_FILE_NAME', then the special
treatment applies to `.' following `/' as well as to `.' at the
beginning of STRING. (The shell uses the `FNM_PERIOD' and
`FNM_FILE_NAME' flags together for matching file names.)
`FNM_NOESCAPE'
Don't treat the `\' character specially in patterns. Normally,
`\' quotes the following character, turning off its special meaning
(if any) so that it matches only itself. When quoting is enabled,
the pattern `\?' matches only the string `?', because the question
mark in the pattern acts like an ordinary character.
If you use `FNM_NOESCAPE', then `\' is an ordinary character.
`FNM_LEADING_DIR'
Ignore a trailing sequence of characters starting with a `/' in
STRING; that is to say, test whether STRING starts with a
directory name that PATTERN matches.
If this flag is set, either `foo*' or `foobar' as a pattern would
match the string `foobar/frobozz'.
`FNM_CASEFOLD'
Ignore case in comparing STRING to PATTERN.
`FNM_EXTMATCH'
Recognize beside the normal patterns also the extended patterns
introduced in `ksh'. The patterns are written in the form
explained in the following table where PATTERN-LIST is a `|'
separated list of patterns.
`?(PATTERN-LIST)'
The pattern matches if zero or one occurrences of any of the
patterns in the PATTERN-LIST allow matching the input string.
`*(PATTERN-LIST)'
The pattern matches if zero or more occurrences of any of the
patterns in the PATTERN-LIST allow matching the input string.
`+(PATTERN-LIST)'
The pattern matches if one or more occurrences of any of the
patterns in the PATTERN-LIST allow matching the input string.
`@(PATTERN-LIST)'
The pattern matches if exactly one occurrence of any of the
patterns in the PATTERN-LIST allows matching the input string.
`!(PATTERN-LIST)'
The pattern matches if the input string cannot be matched
with any of the patterns in the PATTERN-LIST.

File: libc.info, Node: Globbing, Next: Regular Expressions, Prev: Wildcard Matching, Up: Pattern Matching
10.2 Globbing
=============
The archetypal use of wildcards is for matching against the files in a
directory, and making a list of all the matches. This is called
"globbing".
You could do this using `fnmatch', by reading the directory entries
one by one and testing each one with `fnmatch'. But that would be slow
(and complex, since you would have to handle subdirectories by hand).
The library provides a function `glob' to make this particular use
of wildcards convenient. `glob' and the other symbols in this section
are declared in `glob.h'.
* Menu:
* Calling Glob:: Basic use of `glob'.
* Flags for Globbing:: Flags that enable various options in `glob'.
* More Flags for Globbing:: GNU specific extensions to `glob'.

File: libc.info, Node: Calling Glob, Next: Flags for Globbing, Up: Globbing
10.2.1 Calling `glob'
---------------------
The result of globbing is a vector of file names (strings). To return
this vector, `glob' uses a special data type, `glob_t', which is a
structure. You pass `glob' the address of the structure, and it fills
in the structure's fields to tell you about the results.
-- Data Type: glob_t
This data type holds a pointer to a word vector. More precisely,
it records both the address of the word vector and its size. The
GNU implementation contains some more fields which are non-standard
extensions.
`gl_pathc'
The number of elements in the vector, excluding the initial
null entries if the GLOB_DOOFFS flag is used (see gl_offs
below).
`gl_pathv'
The address of the vector. This field has type `char **'.
`gl_offs'
The offset of the first real element of the vector, from its
nominal address in the `gl_pathv' field. Unlike the other
fields, this is always an input to `glob', rather than an
output from it.
If you use a nonzero offset, then that many elements at the
beginning of the vector are left empty. (The `glob' function
fills them with null pointers.)
The `gl_offs' field is meaningful only if you use the
`GLOB_DOOFFS' flag. Otherwise, the offset is always zero
regardless of what is in this field, and the first real
element comes at the beginning of the vector.
`gl_closedir'
The address of an alternative implementation of the `closedir'
function. It is used if the `GLOB_ALTDIRFUNC' bit is set in
the flag parameter. The type of this field is
`void (*) (void *)'.
This is a GNU extension.
`gl_readdir'
The address of an alternative implementation of the `readdir'
function used to read the contents of a directory. It is
used if the `GLOB_ALTDIRFUNC' bit is set in the flag
parameter. The type of this field is
`struct dirent *(*) (void *)'.
This is a GNU extension.
`gl_opendir'
The address of an alternative implementation of the `opendir'
function. It is used if the `GLOB_ALTDIRFUNC' bit is set in
the flag parameter. The type of this field is
`void *(*) (const char *)'.
This is a GNU extension.
`gl_stat'
The address of an alternative implementation of the `stat'
function to get information about an object in the
filesystem. It is used if the `GLOB_ALTDIRFUNC' bit is set
in the flag parameter. The type of this field is
`int (*) (const char *, struct stat *)'.
This is a GNU extension.
`gl_lstat'
The address of an alternative implementation of the `lstat'
function to get information about an object in the
filesystems, not following symbolic links. It is used if the
`GLOB_ALTDIRFUNC' bit is set in the flag parameter. The type
of this field is `int (*) (const char *, struct stat *)'.
This is a GNU extension.
`gl_flags'
The flags used when `glob' was called. In addition,
`GLOB_MAGCHAR' might be set. See *note Flags for Globbing::
for more details.
This is a GNU extension.
For use in the `glob64' function `glob.h' contains another
definition for a very similar type. `glob64_t' differs from `glob_t'
only in the types of the members `gl_readdir', `gl_stat', and
`gl_lstat'.
-- Data Type: glob64_t
This data type holds a pointer to a word vector. More precisely,
it records both the address of the word vector and its size. The
GNU implementation contains some more fields which are non-standard
extensions.
`gl_pathc'
The number of elements in the vector, excluding the initial
null entries if the GLOB_DOOFFS flag is used (see gl_offs
below).
`gl_pathv'
The address of the vector. This field has type `char **'.
`gl_offs'
The offset of the first real element of the vector, from its
nominal address in the `gl_pathv' field. Unlike the other
fields, this is always an input to `glob', rather than an
output from it.
If you use a nonzero offset, then that many elements at the
beginning of the vector are left empty. (The `glob' function
fills them with null pointers.)
The `gl_offs' field is meaningful only if you use the
`GLOB_DOOFFS' flag. Otherwise, the offset is always zero
regardless of what is in this field, and the first real
element comes at the beginning of the vector.
`gl_closedir'
The address of an alternative implementation of the `closedir'
function. It is used if the `GLOB_ALTDIRFUNC' bit is set in
the flag parameter. The type of this field is
`void (*) (void *)'.
This is a GNU extension.
`gl_readdir'
The address of an alternative implementation of the
`readdir64' function used to read the contents of a
directory. It is used if the `GLOB_ALTDIRFUNC' bit is set in
the flag parameter. The type of this field is
`struct dirent64 *(*) (void *)'.
This is a GNU extension.
`gl_opendir'
The address of an alternative implementation of the `opendir'
function. It is used if the `GLOB_ALTDIRFUNC' bit is set in
the flag parameter. The type of this field is
`void *(*) (const char *)'.
This is a GNU extension.
`gl_stat'
The address of an alternative implementation of the `stat64'
function to get information about an object in the
filesystem. It is used if the `GLOB_ALTDIRFUNC' bit is set
in the flag parameter. The type of this field is
`int (*) (const char *, struct stat64 *)'.
This is a GNU extension.
`gl_lstat'
The address of an alternative implementation of the `lstat64'
function to get information about an object in the
filesystems, not following symbolic links. It is used if the
`GLOB_ALTDIRFUNC' bit is set in the flag parameter. The type
of this field is `int (*) (const char *, struct stat64 *)'.
This is a GNU extension.
`gl_flags'
The flags used when `glob' was called. In addition,
`GLOB_MAGCHAR' might be set. See *note Flags for Globbing::
for more details.
This is a GNU extension.
-- Function: int glob (const char *PATTERN, int FLAGS, int (*ERRFUNC)
(const char *FILENAME, int ERROR-CODE), glob_t *VECTOR-PTR)
The function `glob' does globbing using the pattern PATTERN in the
current directory. It puts the result in a newly allocated
vector, and stores the size and address of this vector into
`*VECTOR-PTR'. The argument FLAGS is a combination of bit flags;
see *note Flags for Globbing::, for details of the flags.
The result of globbing is a sequence of file names. The function
`glob' allocates a string for each resulting word, then allocates
a vector of type `char **' to store the addresses of these
strings. The last element of the vector is a null pointer. This
vector is called the "word vector".
To return this vector, `glob' stores both its address and its
length (number of elements, not counting the terminating null
pointer) into `*VECTOR-PTR'.
Normally, `glob' sorts the file names alphabetically before
returning them. You can turn this off with the flag `GLOB_NOSORT'
if you want to get the information as fast as possible. Usually
it's a good idea to let `glob' sort them--if you process the files
in alphabetical order, the users will have a feel for the rate of
progress that your application is making.
If `glob' succeeds, it returns 0. Otherwise, it returns one of
these error codes:
`GLOB_ABORTED'
There was an error opening a directory, and you used the flag
`GLOB_ERR' or your specified ERRFUNC returned a nonzero value.
*Note Flags for Globbing::, for an explanation of the
`GLOB_ERR' flag and ERRFUNC.
`GLOB_NOMATCH'
The pattern didn't match any existing files. If you use the
`GLOB_NOCHECK' flag, then you never get this error code,
because that flag tells `glob' to _pretend_ that the pattern
matched at least one file.
`GLOB_NOSPACE'
It was impossible to allocate memory to hold the result.
In the event of an error, `glob' stores information in
`*VECTOR-PTR' about all the matches it has found so far.
It is important to notice that the `glob' function will not fail if
it encounters directories or files which cannot be handled without
the LFS interfaces. The implementation of `glob' is supposed to
use these functions internally. This at least is the assumptions
made by the Unix standard. The GNU extension of allowing the user
to provide own directory handling and `stat' functions complicates
things a bit. If these callback functions are used and a large
file or directory is encountered `glob' _can_ fail.
-- Function: int glob64 (const char *PATTERN, int FLAGS, int
(*ERRFUNC) (const char *FILENAME, int ERROR-CODE), glob64_t
*VECTOR-PTR)
The `glob64' function was added as part of the Large File Summit
extensions but is not part of the original LFS proposal. The
reason for this is simple: it is not necessary. The necessity for
a `glob64' function is added by the extensions of the GNU `glob'
implementation which allows the user to provide own directory
handling and `stat' functions. The `readdir' and `stat' functions
do depend on the choice of `_FILE_OFFSET_BITS' since the definition
of the types `struct dirent' and `struct stat' will change
depending on the choice.
Beside this difference the `glob64' works just like `glob' in all
aspects.
This function is a GNU extension.

File: libc.info, Node: Flags for Globbing, Next: More Flags for Globbing, Prev: Calling Glob, Up: Globbing
10.2.2 Flags for Globbing
-------------------------
This section describes the standard flags that you can specify in the
FLAGS argument to `glob'. Choose the flags you want, and combine them
with the C bitwise OR operator `|'.
Note that there are *note More Flags for Globbing:: available as GNU
extensions.
`GLOB_APPEND'
Append the words from this expansion to the vector of words
produced by previous calls to `glob'. This way you can
effectively expand several words as if they were concatenated with
spaces between them.
In order for appending to work, you must not modify the contents
of the word vector structure between calls to `glob'. And, if you
set `GLOB_DOOFFS' in the first call to `glob', you must also set
it when you append to the results.
Note that the pointer stored in `gl_pathv' may no longer be valid
after you call `glob' the second time, because `glob' might have
relocated the vector. So always fetch `gl_pathv' from the
`glob_t' structure after each `glob' call; *never* save the
pointer across calls.
`GLOB_DOOFFS'
Leave blank slots at the beginning of the vector of words. The
`gl_offs' field says how many slots to leave. The blank slots
contain null pointers.
`GLOB_ERR'
Give up right away and report an error if there is any difficulty
reading the directories that must be read in order to expand
PATTERN fully. Such difficulties might include a directory in
which you don't have the requisite access. Normally, `glob' tries
its best to keep on going despite any errors, reading whatever
directories it can.
You can exercise even more control than this by specifying an
error-handler function ERRFUNC when you call `glob'. If ERRFUNC
is not a null pointer, then `glob' doesn't give up right away when
it can't read a directory; instead, it calls ERRFUNC with two
arguments, like this:
(*ERRFUNC) (FILENAME, ERROR-CODE)
The argument FILENAME is the name of the directory that `glob'
couldn't open or couldn't read, and ERROR-CODE is the `errno'
value that was reported to `glob'.
If the error handler function returns nonzero, then `glob' gives up
right away. Otherwise, it continues.
`GLOB_MARK'
If the pattern matches the name of a directory, append `/' to the
directory's name when returning it.
`GLOB_NOCHECK'
If the pattern doesn't match any file names, return the pattern
itself as if it were a file name that had been matched.
(Normally, when the pattern doesn't match anything, `glob' returns
that there were no matches.)
`GLOB_NOESCAPE'
Don't treat the `\' character specially in patterns. Normally,
`\' quotes the following character, turning off its special meaning
(if any) so that it matches only itself. When quoting is enabled,
the pattern `\?' matches only the string `?', because the question
mark in the pattern acts like an ordinary character.
If you use `GLOB_NOESCAPE', then `\' is an ordinary character.
`glob' does its work by calling the function `fnmatch' repeatedly.
It handles the flag `GLOB_NOESCAPE' by turning on the
`FNM_NOESCAPE' flag in calls to `fnmatch'.
`GLOB_NOSORT'
Don't sort the file names; return them in no particular order.
(In practice, the order will depend on the order of the entries in
the directory.) The only reason _not_ to sort is to save time.

File: libc.info, Node: More Flags for Globbing, Prev: Flags for Globbing, Up: Globbing
10.2.3 More Flags for Globbing
------------------------------
Beside the flags described in the last section, the GNU implementation
of `glob' allows a few more flags which are also defined in the
`glob.h' file. Some of the extensions implement functionality which is
available in modern shell implementations.
`GLOB_PERIOD'
The `.' character (period) is treated special. It cannot be
matched by wildcards. *Note Wildcard Matching::, `FNM_PERIOD'.
`GLOB_MAGCHAR'
The `GLOB_MAGCHAR' value is not to be given to `glob' in the FLAGS
parameter. Instead, `glob' sets this bit in the GL_FLAGS element
of the GLOB_T structure provided as the result if the pattern used
for matching contains any wildcard character.
`GLOB_ALTDIRFUNC'
Instead of the using the using the normal functions for accessing
the filesystem the `glob' implementation uses the user-supplied
functions specified in the structure pointed to by PGLOB
parameter. For more information about the functions refer to the
sections about directory handling see *note Accessing
Directories::, and *note Reading Attributes::.
`GLOB_BRACE'
If this flag is given the handling of braces in the pattern is
changed. It is now required that braces appear correctly grouped.
I.e., for each opening brace there must be a closing one. Braces
can be used recursively. So it is possible to define one brace
expression in another one. It is important to note that the range
of each brace expression is completely contained in the outer
brace expression (if there is one).
The string between the matching braces is separated into single
expressions by splitting at `,' (comma) characters. The commas
themselves are discarded. Please note what we said above about
recursive brace expressions. The commas used to separate the
subexpressions must be at the same level. Commas in brace
subexpressions are not matched. They are used during expansion of
the brace expression of the deeper level. The example below shows
this
glob ("{foo/{,bar,biz},baz}", GLOB_BRACE, NULL, &result)
is equivalent to the sequence
glob ("foo/", GLOB_BRACE, NULL, &result)
glob ("foo/bar", GLOB_BRACE|GLOB_APPEND, NULL, &result)
glob ("foo/biz", GLOB_BRACE|GLOB_APPEND, NULL, &result)
glob ("baz", GLOB_BRACE|GLOB_APPEND, NULL, &result)
if we leave aside error handling.
`GLOB_NOMAGIC'
If the pattern contains no wildcard constructs (it is a literal
file name), return it as the sole "matching" word, even if no file
exists by that name.
`GLOB_TILDE'
If this flag is used the character `~' (tilde) is handled special
if it appears at the beginning of the pattern. Instead of being
taken verbatim it is used to represent the home directory of a
known user.
If `~' is the only character in pattern or it is followed by a `/'
(slash), the home directory of the process owner is substituted.
Using `getlogin' and `getpwnam' the information is read from the
system databases. As an example take user `bart' with his home
directory at `/home/bart'. For him a call like
glob ("~/bin/*", GLOB_TILDE, NULL, &result)
would return the contents of the directory `/home/bart/bin'.
Instead of referring to the own home directory it is also possible
to name the home directory of other users. To do so one has to
append the user name after the tilde character. So the contents
of user `homer''s `bin' directory can be retrieved by
glob ("~homer/bin/*", GLOB_TILDE, NULL, &result)
If the user name is not valid or the home directory cannot be
determined for some reason the pattern is left untouched and
itself used as the result. I.e., if in the last example `home' is
not available the tilde expansion yields to `"~homer/bin/*"' and
`glob' is not looking for a directory named `~homer'.
This functionality is equivalent to what is available in C-shells
if the `nonomatch' flag is set.
`GLOB_TILDE_CHECK'
If this flag is used `glob' behaves like as if `GLOB_TILDE' is
given. The only difference is that if the user name is not
available or the home directory cannot be determined for other
reasons this leads to an error. `glob' will return `GLOB_NOMATCH'
instead of using the pattern itself as the name.
This functionality is equivalent to what is available in C-shells
if `nonomatch' flag is not set.
`GLOB_ONLYDIR'
If this flag is used the globbing function takes this as a *hint*
that the caller is only interested in directories matching the
pattern. If the information about the type of the file is easily
available non-directories will be rejected but no extra work will
be done to determine the information for each file. I.e., the
caller must still be able to filter directories out.
This functionality is only available with the GNU `glob'
implementation. It is mainly used internally to increase the
performance but might be useful for a user as well and therefore is
documented here.
Calling `glob' will in most cases allocate resources which are used
to represent the result of the function call. If the same object of
type `glob_t' is used in multiple call to `glob' the resources are
freed or reused so that no leaks appear. But this does not include the
time when all `glob' calls are done.
-- Function: void globfree (glob_t *PGLOB)
The `globfree' function frees all resources allocated by previous
calls to `glob' associated with the object pointed to by PGLOB.
This function should be called whenever the currently used
`glob_t' typed object isn't used anymore.
-- Function: void globfree64 (glob64_t *PGLOB)
This function is equivalent to `globfree' but it frees records of
type `glob64_t' which were allocated by `glob64'.

File: libc.info, Node: Regular Expressions, Next: Word Expansion, Prev: Globbing, Up: Pattern Matching
10.3 Regular Expression Matching
================================
The GNU C Library supports two interfaces for matching regular
expressions. One is the standard POSIX.2 interface, and the other is
what the GNU C Library has had for many years.
Both interfaces are declared in the header file `regex.h'. If you
define `_POSIX_C_SOURCE', then only the POSIX.2 functions, structures,
and constants are declared.
* Menu:
* POSIX Regexp Compilation:: Using `regcomp' to prepare to match.
* Flags for POSIX Regexps:: Syntax variations for `regcomp'.
* Matching POSIX Regexps:: Using `regexec' to match the compiled
pattern that you get from `regcomp'.
* Regexp Subexpressions:: Finding which parts of the string were matched.
* Subexpression Complications:: Find points of which parts were matched.
* Regexp Cleanup:: Freeing storage; reporting errors.

File: libc.info, Node: POSIX Regexp Compilation, Next: Flags for POSIX Regexps, Up: Regular Expressions
10.3.1 POSIX Regular Expression Compilation
-------------------------------------------
Before you can actually match a regular expression, you must "compile"
it. This is not true compilation--it produces a special data
structure, not machine instructions. But it is like ordinary
compilation in that its purpose is to enable you to "execute" the
pattern fast. (*Note Matching POSIX Regexps::, for how to use the
compiled regular expression for matching.)
There is a special data type for compiled regular expressions:
-- Data Type: regex_t
This type of object holds a compiled regular expression. It is
actually a structure. It has just one field that your programs
should look at:
`re_nsub'
This field holds the number of parenthetical subexpressions
in the regular expression that was compiled.
There are several other fields, but we don't describe them here,
because only the functions in the library should use them.
After you create a `regex_t' object, you can compile a regular
expression into it by calling `regcomp'.
-- Function: int regcomp (regex_t *restrict COMPILED, const char
*restrict PATTERN, int CFLAGS)
The function `regcomp' "compiles" a regular expression into a data
structure that you can use with `regexec' to match against a
string. The compiled regular expression format is designed for
efficient matching. `regcomp' stores it into `*COMPILED'.
It's up to you to allocate an object of type `regex_t' and pass its
address to `regcomp'.
The argument CFLAGS lets you specify various options that control
the syntax and semantics of regular expressions. *Note Flags for
POSIX Regexps::.
If you use the flag `REG_NOSUB', then `regcomp' omits from the
compiled regular expression the information necessary to record
how subexpressions actually match. In this case, you might as well
pass `0' for the MATCHPTR and NMATCH arguments when you call
`regexec'.
If you don't use `REG_NOSUB', then the compiled regular expression
does have the capacity to record how subexpressions match. Also,
`regcomp' tells you how many subexpressions PATTERN has, by
storing the number in `COMPILED->re_nsub'. You can use that value
to decide how long an array to allocate to hold information about
subexpression matches.
`regcomp' returns `0' if it succeeds in compiling the regular
expression; otherwise, it returns a nonzero error code (see the
table below). You can use `regerror' to produce an error message
string describing the reason for a nonzero value; see *note Regexp
Cleanup::.
Here are the possible nonzero values that `regcomp' can return:
`REG_BADBR'
There was an invalid `\{...\}' construct in the regular
expression. A valid `\{...\}' construct must contain either a
single number, or two numbers in increasing order separated by a
comma.
`REG_BADPAT'
There was a syntax error in the regular expression.
`REG_BADRPT'
A repetition operator such as `?' or `*' appeared in a bad
position (with no preceding subexpression to act on).
`REG_ECOLLATE'
The regular expression referred to an invalid collating element
(one not defined in the current locale for string collation).
*Note Locale Categories::.
`REG_ECTYPE'
The regular expression referred to an invalid character class name.
`REG_EESCAPE'
The regular expression ended with `\'.
`REG_ESUBREG'
There was an invalid number in the `\DIGIT' construct.
`REG_EBRACK'
There were unbalanced square brackets in the regular expression.
`REG_EPAREN'
An extended regular expression had unbalanced parentheses, or a
basic regular expression had unbalanced `\(' and `\)'.
`REG_EBRACE'
The regular expression had unbalanced `\{' and `\}'.
`REG_ERANGE'
One of the endpoints in a range expression was invalid.
`REG_ESPACE'
`regcomp' ran out of memory.

File: libc.info, Node: Flags for POSIX Regexps, Next: Matching POSIX Regexps, Prev: POSIX Regexp Compilation, Up: Regular Expressions
10.3.2 Flags for POSIX Regular Expressions
------------------------------------------
These are the bit flags that you can use in the CFLAGS operand when
compiling a regular expression with `regcomp'.
`REG_EXTENDED'
Treat the pattern as an extended regular expression, rather than
as a basic regular expression.
`REG_ICASE'
Ignore case when matching letters.
`REG_NOSUB'
Don't bother storing the contents of the MATCHES-PTR array.
`REG_NEWLINE'
Treat a newline in STRING as dividing STRING into multiple lines,
so that `$' can match before the newline and `^' can match after.
Also, don't permit `.' to match a newline, and don't permit
`[^...]' to match a newline.
Otherwise, newline acts like any other ordinary character.

File: libc.info, Node: Matching POSIX Regexps, Next: Regexp Subexpressions, Prev: Flags for POSIX Regexps, Up: Regular Expressions
10.3.3 Matching a Compiled POSIX Regular Expression
---------------------------------------------------
Once you have compiled a regular expression, as described in *note
POSIX Regexp Compilation::, you can match it against strings using
`regexec'. A match anywhere inside the string counts as success,
unless the regular expression contains anchor characters (`^' or `$').
-- Function: int regexec (const regex_t *restrict COMPILED, const char
*restrict STRING, size_t NMATCH, regmatch_t
MATCHPTR[restrict], int EFLAGS)
This function tries to match the compiled regular expression
`*COMPILED' against STRING.
`regexec' returns `0' if the regular expression matches;
otherwise, it returns a nonzero value. See the table below for
what nonzero values mean. You can use `regerror' to produce an
error message string describing the reason for a nonzero value;
see *note Regexp Cleanup::.
The argument EFLAGS is a word of bit flags that enable various
options.
If you want to get information about what part of STRING actually
matched the regular expression or its subexpressions, use the
arguments MATCHPTR and NMATCH. Otherwise, pass `0' for NMATCH,
and `NULL' for MATCHPTR. *Note Regexp Subexpressions::.
You must match the regular expression with the same set of current
locales that were in effect when you compiled the regular expression.
The function `regexec' accepts the following flags in the EFLAGS
argument:
`REG_NOTBOL'
Do not regard the beginning of the specified string as the
beginning of a line; more generally, don't make any assumptions
about what text might precede it.
`REG_NOTEOL'
Do not regard the end of the specified string as the end of a
line; more generally, don't make any assumptions about what text
might follow it.
Here are the possible nonzero values that `regexec' can return:
`REG_NOMATCH'
The pattern didn't match the string. This isn't really an error.
`REG_ESPACE'
`regexec' ran out of memory.

File: libc.info, Node: Regexp Subexpressions, Next: Subexpression Complications, Prev: Matching POSIX Regexps, Up: Regular Expressions
10.3.4 Match Results with Subexpressions
----------------------------------------
When `regexec' matches parenthetical subexpressions of PATTERN, it
records which parts of STRING they match. It returns that information
by storing the offsets into an array whose elements are structures of
type `regmatch_t'. The first element of the array (index `0') records
the part of the string that matched the entire regular expression.
Each other element of the array records the beginning and end of the
part that matched a single parenthetical subexpression.
-- Data Type: regmatch_t
This is the data type of the MATCHARRAY array that you pass to
`regexec'. It contains two structure fields, as follows:
`rm_so'
The offset in STRING of the beginning of a substring. Add
this value to STRING to get the address of that part.
`rm_eo'
The offset in STRING of the end of the substring.
-- Data Type: regoff_t
`regoff_t' is an alias for another signed integer type. The
fields of `regmatch_t' have type `regoff_t'.
The `regmatch_t' elements correspond to subexpressions positionally;
the first element (index `1') records where the first subexpression
matched, the second element records the second subexpression, and so
on. The order of the subexpressions is the order in which they begin.
When you call `regexec', you specify how long the MATCHPTR array is,
with the NMATCH argument. This tells `regexec' how many elements to
store. If the actual regular expression has more than NMATCH
subexpressions, then you won't get offset information about the rest of
them. But this doesn't alter whether the pattern matches a particular
string or not.
If you don't want `regexec' to return any information about where
the subexpressions matched, you can either supply `0' for NMATCH, or
use the flag `REG_NOSUB' when you compile the pattern with `regcomp'.

File: libc.info, Node: Subexpression Complications, Next: Regexp Cleanup, Prev: Regexp Subexpressions, Up: Regular Expressions
10.3.5 Complications in Subexpression Matching
----------------------------------------------
Sometimes a subexpression matches a substring of no characters. This
happens when `f\(o*\)' matches the string `fum'. (It really matches
just the `f'.) In this case, both of the offsets identify the point in
the string where the null substring was found. In this example, the
offsets are both `1'.
Sometimes the entire regular expression can match without using some
of its subexpressions at all--for example, when `ba\(na\)*' matches the
string `ba', the parenthetical subexpression is not used. When this
happens, `regexec' stores `-1' in both fields of the element for that
subexpression.
Sometimes matching the entire regular expression can match a
particular subexpression more than once--for example, when `ba\(na\)*'
matches the string `bananana', the parenthetical subexpression matches
three times. When this happens, `regexec' usually stores the offsets
of the last part of the string that matched the subexpression. In the
case of `bananana', these offsets are `6' and `8'.
But the last match is not always the one that is chosen. It's more
accurate to say that the last _opportunity_ to match is the one that
takes precedence. What this means is that when one subexpression
appears within another, then the results reported for the inner
subexpression reflect whatever happened on the last match of the outer
subexpression. For an example, consider `\(ba\(na\)*s \)*' matching
the string `bananas bas '. The last time the inner expression actually
matches is near the end of the first word. But it is _considered_
again in the second word, and fails to match there. `regexec' reports
nonuse of the "na" subexpression.
Another place where this rule applies is when the regular expression
\(ba\(na\)*s \|nefer\(ti\)* \)*
matches `bananas nefertiti'. The "na" subexpression does match in
the first word, but it doesn't match in the second word because the
other alternative is used there. Once again, the second repetition of
the outer subexpression overrides the first, and within that second
repetition, the "na" subexpression is not used. So `regexec' reports
nonuse of the "na" subexpression.

File: libc.info, Node: Regexp Cleanup, Prev: Subexpression Complications, Up: Regular Expressions
10.3.6 POSIX Regexp Matching Cleanup
------------------------------------
When you are finished using a compiled regular expression, you can free
the storage it uses by calling `regfree'.
-- Function: void regfree (regex_t *COMPILED)
Calling `regfree' frees all the storage that `*COMPILED' points
to. This includes various internal fields of the `regex_t'
structure that aren't documented in this manual.
`regfree' does not free the object `*COMPILED' itself.
You should always free the space in a `regex_t' structure with
`regfree' before using the structure to compile another regular
expression.
When `regcomp' or `regexec' reports an error, you can use the
function `regerror' to turn it into an error message string.
-- Function: size_t regerror (int ERRCODE, const regex_t *restrict
COMPILED, char *restrict BUFFER, size_t LENGTH)
This function produces an error message string for the error code
ERRCODE, and stores the string in LENGTH bytes of memory starting
at BUFFER. For the COMPILED argument, supply the same compiled
regular expression structure that `regcomp' or `regexec' was
working with when it got the error. Alternatively, you can supply
`NULL' for COMPILED; you will still get a meaningful error
message, but it might not be as detailed.
If the error message can't fit in LENGTH bytes (including a
terminating null character), then `regerror' truncates it. The
string that `regerror' stores is always null-terminated even if it
has been truncated.
The return value of `regerror' is the minimum length needed to
store the entire error message. If this is less than LENGTH, then
the error message was not truncated, and you can use it.
Otherwise, you should call `regerror' again with a larger buffer.
Here is a function which uses `regerror', but always dynamically
allocates a buffer for the error message:
char *get_regerror (int errcode, regex_t *compiled)
{
size_t length = regerror (errcode, compiled, NULL, 0);
char *buffer = xmalloc (length);
(void) regerror (errcode, compiled, buffer, length);
return buffer;
}

File: libc.info, Node: Word Expansion, Prev: Regular Expressions, Up: Pattern Matching
10.4 Shell-Style Word Expansion
===============================
"Word expansion" means the process of splitting a string into "words"
and substituting for variables, commands, and wildcards just as the
shell does.
For example, when you write `ls -l foo.c', this string is split into
three separate words--`ls', `-l' and `foo.c'. This is the most basic
function of word expansion.
When you write `ls *.c', this can become many words, because the
word `*.c' can be replaced with any number of file names. This is
called "wildcard expansion", and it is also a part of word expansion.
When you use `echo $PATH' to print your path, you are taking
advantage of "variable substitution", which is also part of word
expansion.
Ordinary programs can perform word expansion just like the shell by
calling the library function `wordexp'.
* Menu:
* Expansion Stages:: What word expansion does to a string.
* Calling Wordexp:: How to call `wordexp'.
* Flags for Wordexp:: Options you can enable in `wordexp'.
* Wordexp Example:: A sample program that does word expansion.
* Tilde Expansion:: Details of how tilde expansion works.
* Variable Substitution:: Different types of variable substitution.

File: libc.info, Node: Expansion Stages, Next: Calling Wordexp, Up: Word Expansion
10.4.1 The Stages of Word Expansion
-----------------------------------
When word expansion is applied to a sequence of words, it performs the
following transformations in the order shown here:
1. "Tilde expansion": Replacement of `~foo' with the name of the home
directory of `foo'.
2. Next, three different transformations are applied in the same step,
from left to right:
* "Variable substitution": Environment variables are
substituted for references such as `$foo'.
* "Command substitution": Constructs such as ``cat foo`' and
the equivalent `$(cat foo)' are replaced with the output from
the inner command.
* "Arithmetic expansion": Constructs such as `$(($x-1))' are
replaced with the result of the arithmetic computation.
3. "Field splitting": subdivision of the text into "words".
4. "Wildcard expansion": The replacement of a construct such as `*.c'
with a list of `.c' file names. Wildcard expansion applies to an
entire word at a time, and replaces that word with 0 or more file
names that are themselves words.
5. "Quote removal": The deletion of string-quotes, now that they have
done their job by inhibiting the above transformations when
appropriate.
For the details of these transformations, and how to write the
constructs that use them, see `The BASH Manual' (to appear).

File: libc.info, Node: Calling Wordexp, Next: Flags for Wordexp, Prev: Expansion Stages, Up: Word Expansion
10.4.2 Calling `wordexp'
------------------------
All the functions, constants and data types for word expansion are
declared in the header file `wordexp.h'.
Word expansion produces a vector of words (strings). To return this
vector, `wordexp' uses a special data type, `wordexp_t', which is a
structure. You pass `wordexp' the address of the structure, and it
fills in the structure's fields to tell you about the results.
-- Data Type: wordexp_t
This data type holds a pointer to a word vector. More precisely,
it records both the address of the word vector and its size.
`we_wordc'
The number of elements in the vector.
`we_wordv'
The address of the vector. This field has type `char **'.
`we_offs'
The offset of the first real element of the vector, from its
nominal address in the `we_wordv' field. Unlike the other
fields, this is always an input to `wordexp', rather than an
output from it.
If you use a nonzero offset, then that many elements at the
beginning of the vector are left empty. (The `wordexp'
function fills them with null pointers.)
The `we_offs' field is meaningful only if you use the
`WRDE_DOOFFS' flag. Otherwise, the offset is always zero
regardless of what is in this field, and the first real
element comes at the beginning of the vector.
-- Function: int wordexp (const char *WORDS, wordexp_t
*WORD-VECTOR-PTR, int FLAGS)
Perform word expansion on the string WORDS, putting the result in
a newly allocated vector, and store the size and address of this
vector into `*WORD-VECTOR-PTR'. The argument FLAGS is a
combination of bit flags; see *note Flags for Wordexp::, for
details of the flags.
You shouldn't use any of the characters `|&;<>' in the string
WORDS unless they are quoted; likewise for newline. If you use
these characters unquoted, you will get the `WRDE_BADCHAR' error
code. Don't use parentheses or braces unless they are quoted or
part of a word expansion construct. If you use quotation
characters `'"`', they should come in pairs that balance.
The results of word expansion are a sequence of words. The
function `wordexp' allocates a string for each resulting word, then
allocates a vector of type `char **' to store the addresses of
these strings. The last element of the vector is a null pointer.
This vector is called the "word vector".
To return this vector, `wordexp' stores both its address and its
length (number of elements, not counting the terminating null
pointer) into `*WORD-VECTOR-PTR'.
If `wordexp' succeeds, it returns 0. Otherwise, it returns one of
these error codes:
`WRDE_BADCHAR'
The input string WORDS contains an unquoted invalid character
such as `|'.
`WRDE_BADVAL'
The input string refers to an undefined shell variable, and
you used the flag `WRDE_UNDEF' to forbid such references.
`WRDE_CMDSUB'
The input string uses command substitution, and you used the
flag `WRDE_NOCMD' to forbid command substitution.
`WRDE_NOSPACE'
It was impossible to allocate memory to hold the result. In
this case, `wordexp' can store part of the results--as much
as it could allocate room for.
`WRDE_SYNTAX'
There was a syntax error in the input string. For example,
an unmatched quoting character is a syntax error.
-- Function: void wordfree (wordexp_t *WORD-VECTOR-PTR)
Free the storage used for the word-strings and vector that
`*WORD-VECTOR-PTR' points to. This does not free the structure
`*WORD-VECTOR-PTR' itself--only the other data it points to.

File: libc.info, Node: Flags for Wordexp, Next: Wordexp Example, Prev: Calling Wordexp, Up: Word Expansion
10.4.3 Flags for Word Expansion
-------------------------------
This section describes the flags that you can specify in the FLAGS
argument to `wordexp'. Choose the flags you want, and combine them
with the C operator `|'.
`WRDE_APPEND'
Append the words from this expansion to the vector of words
produced by previous calls to `wordexp'. This way you can
effectively expand several words as if they were concatenated with
spaces between them.
In order for appending to work, you must not modify the contents
of the word vector structure between calls to `wordexp'. And, if
you set `WRDE_DOOFFS' in the first call to `wordexp', you must also
set it when you append to the results.
`WRDE_DOOFFS'
Leave blank slots at the beginning of the vector of words. The
`we_offs' field says how many slots to leave. The blank slots
contain null pointers.
`WRDE_NOCMD'
Don't do command substitution; if the input requests command
substitution, report an error.
`WRDE_REUSE'
Reuse a word vector made by a previous call to `wordexp'. Instead
of allocating a new vector of words, this call to `wordexp' will
use the vector that already exists (making it larger if necessary).
Note that the vector may move, so it is not safe to save an old
pointer and use it again after calling `wordexp'. You must fetch
`we_pathv' anew after each call.
`WRDE_SHOWERR'
Do show any error messages printed by commands run by command
substitution. More precisely, allow these commands to inherit the
standard error output stream of the current process. By default,
`wordexp' gives these commands a standard error stream that
discards all output.
`WRDE_UNDEF'
If the input refers to a shell variable that is not defined,
report an error.

File: libc.info, Node: Wordexp Example, Next: Tilde Expansion, Prev: Flags for Wordexp, Up: Word Expansion
10.4.4 `wordexp' Example
------------------------
Here is an example of using `wordexp' to expand several strings and use
the results to run a shell command. It also shows the use of
`WRDE_APPEND' to concatenate the expansions and of `wordfree' to free
the space allocated by `wordexp'.
int
expand_and_execute (const char *program, const char **options)
{
wordexp_t result;
pid_t pid
int status, i;
/* Expand the string for the program to run. */
switch (wordexp (program, &result, 0))
{
case 0: /* Successful. */
break;
case WRDE_NOSPACE:
/* If the error was `WRDE_NOSPACE',
then perhaps part of the result was allocated. */
wordfree (&result);
default: /* Some other error. */
return -1;
}
/* Expand the strings specified for the arguments. */
for (i = 0; options[i] != NULL; i++)
{
if (wordexp (options[i], &result, WRDE_APPEND))
{
wordfree (&result);
return -1;
}
}
pid = fork ();
if (pid == 0)
{
/* This is the child process. Execute the command. */
execv (result.we_wordv[0], result.we_wordv);
exit (EXIT_FAILURE);
}
else if (pid < 0)
/* The fork failed. Report failure. */
status = -1;
else
/* This is the parent process. Wait for the child to complete. */
if (waitpid (pid, &status, 0) != pid)
status = -1;
wordfree (&result);
return status;
}

File: libc.info, Node: Tilde Expansion, Next: Variable Substitution, Prev: Wordexp Example, Up: Word Expansion
10.4.5 Details of Tilde Expansion
---------------------------------
It's a standard part of shell syntax that you can use `~' at the
beginning of a file name to stand for your own home directory. You can
use `~USER' to stand for USER's home directory.
"Tilde expansion" is the process of converting these abbreviations
to the directory names that they stand for.
Tilde expansion applies to the `~' plus all following characters up
to whitespace or a slash. It takes place only at the beginning of a
word, and only if none of the characters to be transformed is quoted in
any way.
Plain `~' uses the value of the environment variable `HOME' as the
proper home directory name. `~' followed by a user name uses
`getpwname' to look up that user in the user database, and uses
whatever directory is recorded there. Thus, `~' followed by your own
name can give different results from plain `~', if the value of `HOME'
is not really your home directory.

File: libc.info, Node: Variable Substitution, Prev: Tilde Expansion, Up: Word Expansion
10.4.6 Details of Variable Substitution
---------------------------------------
Part of ordinary shell syntax is the use of `$VARIABLE' to substitute
the value of a shell variable into a command. This is called "variable
substitution", and it is one part of doing word expansion.
There are two basic ways you can write a variable reference for
substitution:
`${VARIABLE}'
If you write braces around the variable name, then it is completely
unambiguous where the variable name ends. You can concatenate
additional letters onto the end of the variable value by writing
them immediately after the close brace. For example, `${foo}s'
expands into `tractors'.
`$VARIABLE'
If you do not put braces around the variable name, then the
variable name consists of all the alphanumeric characters and
underscores that follow the `$'. The next punctuation character
ends the variable name. Thus, `$foo-bar' refers to the variable
`foo' and expands into `tractor-bar'.
When you use braces, you can also use various constructs to modify
the value that is substituted, or test it in various ways.
`${VARIABLE:-DEFAULT}'
Substitute the value of VARIABLE, but if that is empty or
undefined, use DEFAULT instead.
`${VARIABLE:=DEFAULT}'
Substitute the value of VARIABLE, but if that is empty or
undefined, use DEFAULT instead and set the variable to DEFAULT.
`${VARIABLE:?MESSAGE}'
If VARIABLE is defined and not empty, substitute its value.
Otherwise, print MESSAGE as an error message on the standard error
stream, and consider word expansion a failure.
`${VARIABLE:+REPLACEMENT}'
Substitute REPLACEMENT, but only if VARIABLE is defined and
nonempty. Otherwise, substitute nothing for this construct.
`${#VARIABLE}'
Substitute a numeral which expresses in base ten the number of
characters in the value of VARIABLE. `${#foo}' stands for `7',
because `tractor' is seven characters.
These variants of variable substitution let you remove part of the
variable's value before substituting it. The PREFIX and SUFFIX are not
mere strings; they are wildcard patterns, just like the patterns that
you use to match multiple file names. But in this context, they match
against parts of the variable value rather than against file names.
`${VARIABLE%%SUFFIX}'
Substitute the value of VARIABLE, but first discard from that
variable any portion at the end that matches the pattern SUFFIX.
If there is more than one alternative for how to match against
SUFFIX, this construct uses the longest possible match.
Thus, `${foo%%r*}' substitutes `t', because the largest match for
`r*' at the end of `tractor' is `ractor'.
`${VARIABLE%SUFFIX}'
Substitute the value of VARIABLE, but first discard from that
variable any portion at the end that matches the pattern SUFFIX.
If there is more than one alternative for how to match against
SUFFIX, this construct uses the shortest possible alternative.
Thus, `${foo%r*}' substitutes `tracto', because the shortest match
for `r*' at the end of `tractor' is just `r'.
`${VARIABLE##PREFIX}'
Substitute the value of VARIABLE, but first discard from that
variable any portion at the beginning that matches the pattern
PREFIX.
If there is more than one alternative for how to match against
PREFIX, this construct uses the longest possible match.
Thus, `${foo##*t}' substitutes `or', because the largest match for
`*t' at the beginning of `tractor' is `tract'.
`${VARIABLE#PREFIX}'
Substitute the value of VARIABLE, but first discard from that
variable any portion at the beginning that matches the pattern
PREFIX.
If there is more than one alternative for how to match against
PREFIX, this construct uses the shortest possible alternative.
Thus, `${foo#*t}' substitutes `ractor', because the shortest match
for `*t' at the beginning of `tractor' is just `t'.

File: libc.info, Node: I/O Overview, Next: I/O on Streams, Prev: Pattern Matching, Up: Top
11 Input/Output Overview
************************
Most programs need to do either input (reading data) or output (writing
data), or most frequently both, in order to do anything useful. The
GNU C Library provides such a large selection of input and output
functions that the hardest part is often deciding which function is most
appropriate!
This chapter introduces concepts and terminology relating to input
and output. Other chapters relating to the GNU I/O facilities are:
* *note I/O on Streams::, which covers the high-level functions that
operate on streams, including formatted input and output.
* *note Low-Level I/O::, which covers the basic I/O and control
functions on file descriptors.
* *note File System Interface::, which covers functions for
operating on directories and for manipulating file attributes such
as access modes and ownership.
* *note Pipes and FIFOs::, which includes information on the basic
interprocess communication facilities.
* *note Sockets::, which covers a more complicated interprocess
communication facility with support for networking.
* *note Low-Level Terminal Interface::, which covers functions for
changing how input and output to terminals or other serial devices
are processed.
* Menu:
* I/O Concepts:: Some basic information and terminology.
* File Names:: How to refer to a file.

File: libc.info, Node: I/O Concepts, Next: File Names, Up: I/O Overview
11.1 Input/Output Concepts
==========================
Before you can read or write the contents of a file, you must establish
a connection or communications channel to the file. This process is
called "opening" the file. You can open a file for reading, writing,
or both.
The connection to an open file is represented either as a stream or
as a file descriptor. You pass this as an argument to the functions
that do the actual read or write operations, to tell them which file to
operate on. Certain functions expect streams, and others are designed
to operate on file descriptors.
When you have finished reading to or writing from the file, you can
terminate the connection by "closing" the file. Once you have closed a
stream or file descriptor, you cannot do any more input or output
operations on it.
* Menu:
* Streams and File Descriptors:: The GNU C Library provides two ways
to access the contents of files.
* File Position:: The number of bytes from the
beginning of the file.

File: libc.info, Node: Streams and File Descriptors, Next: File Position, Up: I/O Concepts
11.1.1 Streams and File Descriptors
-----------------------------------
When you want to do input or output to a file, you have a choice of two
basic mechanisms for representing the connection between your program
and the file: file descriptors and streams. File descriptors are
represented as objects of type `int', while streams are represented as
`FILE *' objects.
File descriptors provide a primitive, low-level interface to input
and output operations. Both file descriptors and streams can represent
a connection to a device (such as a terminal), or a pipe or socket for
communicating with another process, as well as a normal file. But, if
you want to do control operations that are specific to a particular kind
of device, you must use a file descriptor; there are no facilities to
use streams in this way. You must also use file descriptors if your