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This is /home/vagrant/rpmbuild/BUILD/build-eglibc/manual/,
produced by makeinfo version 4.13 from libc.texinfo.
INFO-DIR-SECTION Software libraries
* Libc: (libc). C library.
INFO-DIR-SECTION GNU C library functions and macros
* 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.
* 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.
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:, Node: Top, Next: Introduction, Prev: (dir), Up: (dir)
Main Menu
This is `The GNU C Library Reference Manual', for Version 2.18-2013.10
(EGLIBC) of the GNU C Library.
* Menu:
* Introduction:: Purpose of the GNU C Library.
* Error Reporting:: How library functions report errors.
* Memory:: Allocating virtual memory and controlling
* Character Handling:: Character testing and conversion functions.
* String and Array Utilities:: Utilities for copying and comparing strings
and arrays.
* Character Set Handling:: Support for extended character sets.
* Locales:: The country and language can affect the
behavior of library functions.
* Message Translation:: How to make the program speak the user's
* Searching and Sorting:: General searching and sorting functions.
* Pattern Matching:: Matching shell ``globs'' and regular
* I/O Overview:: Introduction to the I/O facilities.
* I/O on Streams:: High-level, portable I/O facilities.
* Low-Level I/O:: Low-level, less portable I/O.
* File System Interface:: Functions for manipulating files.
* Pipes and FIFOs:: A simple interprocess communication
* Sockets:: A more complicated IPC mechanism, with
networking support.
* Low-Level Terminal Interface:: How to change the characteristics of a
terminal device.
* Syslog:: System logging and messaging.
* Mathematics:: Math functions, useful constants, random
* Arithmetic:: Low level arithmetic functions.
* Date and Time:: Functions for getting the date and time and
formatting them nicely.
* Resource Usage And Limitation:: Functions for examining resource usage and
getting and setting limits.
* Non-Local Exits:: Jumping out of nested function calls.
* Signal Handling:: How to send, block, and handle signals.
* Program Basics:: Writing the beginning and end of your
* Processes:: How to create processes and run other
* Job Control:: All about process groups and sessions.
* Name Service Switch:: Accessing system databases.
* Users and Groups:: How users are identified and classified.
* System Management:: Controlling the system and getting
information about it.
* System Configuration:: Parameters describing operating system
* Cryptographic Functions:: DES encryption and password handling.
* Debugging Support:: Functions to help debugging applications.
* POSIX Threads:: POSIX Threads.
* Language Features:: C language features provided by the library.
* Library Summary:: A summary showing the syntax, header file,
and derivation of each library feature.
* Installation:: How to install the GNU C Library.
* Maintenance:: How to enhance and port the GNU C Library.
* Platform:: Describe all platform-specific facilities
* Contributors:: Who wrote what parts of the GNU C Library.
* Free Manuals:: Free Software Needs Free Documentation.
* Copying:: The GNU Lesser General Public License says
how you can copy and share the GNU C Library.
* Documentation License:: This manual is under the GNU Free
Documentation License.
* Concept Index:: Index of concepts and names.
* Type Index:: Index of types and type qualifiers.
* Function Index:: Index of functions and function-like macros.
* Variable Index:: Index of variables and variable-like macros.
* File Index:: Index of programs and files.
--- The Detailed Node Listing ---
* Getting Started:: What this manual is for and how to use it.
* Standards and Portability:: Standards and sources upon which the GNU
C library is based.
* Using the Library:: Some practical uses for the library.
* Roadmap to the Manual:: Overview of the remaining chapters in
this manual.
Standards and Portability
* ISO C:: The international standard for the C
programming language.
* POSIX:: The ISO/IEC 9945 (aka IEEE 1003) standards
for operating systems.
* Berkeley Unix:: BSD and SunOS.
* SVID:: The System V Interface Description.
* XPG:: The X/Open Portability Guide.
Using the Library
* Header Files:: How to include the header files in your
* Macro Definitions:: Some functions in the library may really
be implemented as macros.
* Reserved Names:: The C standard reserves some names for
the library, and some for users.
* Feature Test Macros:: How to control what names are defined.
Error Reporting
* Checking for Errors:: How errors are reported by library functions.
* Error Codes:: Error code macros; all of these expand
into integer constant values.
* Error Messages:: Mapping error codes onto error messages.
* Memory Concepts:: An introduction to concepts and terminology.
* Memory Allocation:: Allocating storage for your program data
* Resizing the Data Segment:: `brk', `sbrk'
* Locking Pages:: Preventing page faults
Memory Allocation
* Memory Allocation and C:: How to get different kinds of allocation in C.
* Unconstrained Allocation:: The `malloc' facility allows fully general
dynamic allocation.
* Allocation Debugging:: Finding memory leaks and not freed memory.
* Obstacks:: Obstacks are less general than malloc
but more efficient and convenient.
* Variable Size Automatic:: Allocation of variable-sized blocks
of automatic storage that are freed when the
calling function returns.
Unconstrained Allocation
* Basic Allocation:: Simple use of `malloc'.
* Malloc Examples:: Examples of `malloc'. `xmalloc'.
* Freeing after Malloc:: Use `free' to free a block you
got with `malloc'.
* Changing Block Size:: Use `realloc' to make a block
bigger or smaller.
* Allocating Cleared Space:: Use `calloc' to allocate a
block and clear it.
* Efficiency and Malloc:: Efficiency considerations in use of
these functions.
* Aligned Memory Blocks:: Allocating specially aligned memory.
* Malloc Tunable Parameters:: Use `mallopt' to adjust allocation
* Heap Consistency Checking:: Automatic checking for errors.
* Hooks for Malloc:: You can use these hooks for debugging
programs that use `malloc'.
* Statistics of Malloc:: Getting information about how much
memory your program is using.
* Summary of Malloc:: Summary of `malloc' and related functions.
Allocation Debugging
* Tracing malloc:: How to install the tracing functionality.
* Using the Memory Debugger:: Example programs excerpts.
* Tips for the Memory Debugger:: Some more or less clever ideas.
* Interpreting the traces:: What do all these lines mean?
* Creating Obstacks:: How to declare an obstack in your program.
* Preparing for Obstacks:: Preparations needed before you can
use obstacks.
* Allocation in an Obstack:: Allocating objects in an obstack.
* Freeing Obstack Objects:: Freeing objects in an obstack.
* Obstack Functions:: The obstack functions are both
functions and macros.
* Growing Objects:: Making an object bigger by stages.
* Extra Fast Growing:: Extra-high-efficiency (though more
complicated) growing objects.
* Status of an Obstack:: Inquiries about the status of an obstack.
* Obstacks Data Alignment:: Controlling alignment of objects in obstacks.
* Obstack Chunks:: How obstacks obtain and release chunks;
efficiency considerations.
* Summary of Obstacks::
Variable Size Automatic
* Alloca Example:: Example of using `alloca'.
* Advantages of Alloca:: Reasons to use `alloca'.
* Disadvantages of Alloca:: Reasons to avoid `alloca'.
* GNU C Variable-Size Arrays:: Only in GNU C, here is an alternative
method of allocating dynamically and
freeing automatically.
Locking Pages
* Why Lock Pages:: Reasons to read this section.
* Locked Memory Details:: Everything you need to know locked
* Page Lock Functions:: Here's how to do it.
Character Handling
* Classification of Characters:: Testing whether characters are
letters, digits, punctuation, etc.
* Case Conversion:: Case mapping, and the like.
* Classification of Wide Characters:: Character class determination for
wide characters.
* Using Wide Char Classes:: Notes on using the wide character
* Wide Character Case Conversion:: Mapping of wide characters.
String and Array Utilities
* Representation of Strings:: Introduction to basic concepts.
* String/Array Conventions:: Whether to use a string function or an
arbitrary array function.
* String Length:: Determining the length of a string.
* Copying and Concatenation:: Functions to copy the contents of strings
and arrays.
* String/Array Comparison:: Functions for byte-wise and character-wise
* Collation Functions:: Functions for collating strings.
* Search Functions:: Searching for a specific element or substring.
* Finding Tokens in a String:: Splitting a string into tokens by looking
for delimiters.
* strfry:: Function for flash-cooking a string.
* Trivial Encryption:: Obscuring data.
* Encode Binary Data:: Encoding and Decoding of Binary Data.
* Argz and Envz Vectors:: Null-separated string vectors.
Argz and Envz Vectors
* Argz Functions:: Operations on argz vectors.
* Envz Functions:: Additional operations on environment vectors.
Character Set Handling
* Extended Char Intro:: Introduction to Extended Characters.
* Charset Function Overview:: Overview about Character Handling
* Restartable multibyte conversion:: Restartable multibyte conversion
* Non-reentrant Conversion:: Non-reentrant Conversion Function.
* Generic Charset Conversion:: Generic Charset Conversion.
Restartable multibyte conversion
* Selecting the Conversion:: Selecting the conversion and its properties.
* Keeping the state:: Representing the state of the conversion.
* Converting a Character:: Converting Single Characters.
* Converting Strings:: Converting Multibyte and Wide Character
* Multibyte Conversion Example:: A Complete Multibyte Conversion Example.
Non-reentrant Conversion
* Non-reentrant Character Conversion:: Non-reentrant Conversion of Single
* Non-reentrant String Conversion:: Non-reentrant Conversion of Strings.
* Shift State:: States in Non-reentrant Functions.
Generic Charset Conversion
* Generic Conversion Interface:: Generic Character Set Conversion Interface.
* iconv Examples:: A complete `iconv' example.
* Other iconv Implementations:: Some Details about other `iconv'
* glibc iconv Implementation:: The `iconv' Implementation in the GNU C
* Effects of Locale:: Actions affected by the choice of
* Choosing Locale:: How the user specifies a locale.
* Locale Categories:: Different purposes for which you can
select a locale.
* Setting the Locale:: How a program specifies the locale
with library functions.
* Standard Locales:: Locale names available on all systems.
* Locale Names:: Format of system-specific locale names.
* Locale Information:: How to access the information for the locale.
* Formatting Numbers:: A dedicated function to format numbers.
* Yes-or-No Questions:: Check a Response against the locale.
Locale Information
* The Lame Way to Locale Data:: ISO C's `localeconv'.
* The Elegant and Fast Way:: X/Open's `nl_langinfo'.
The Lame Way to Locale Data
* General Numeric:: Parameters for formatting numbers and
currency amounts.
* Currency Symbol:: How to print the symbol that identifies an
amount of money (e.g. `$').
* Sign of Money Amount:: How to print the (positive or negative) sign
for a monetary amount, if one exists.
Message Translation
* Message catalogs a la X/Open:: The `catgets' family of functions.
* The Uniforum approach:: The `gettext' family of functions.
Message catalogs a la X/Open
* The catgets Functions:: The `catgets' function family.
* The message catalog files:: Format of the message catalog files.
* The gencat program:: How to generate message catalogs files which
can be used by the functions.
* Common Usage:: How to use the `catgets' interface.
The Uniforum approach
* Message catalogs with gettext:: The `gettext' family of functions.
* Helper programs for gettext:: Programs to handle message catalogs
for `gettext'.
Message catalogs with gettext
* Translation with gettext:: What has to be done to translate a message.
* Locating gettext catalog:: How to determine which catalog to be used.
* Advanced gettext functions:: Additional functions for more complicated
* Charset conversion in gettext:: How to specify the output character set
`gettext' uses.
* GUI program problems:: How to use `gettext' in GUI programs.
* Using gettextized software:: The possibilities of the user to influence
the way `gettext' works.
Searching and Sorting
* Comparison Functions:: Defining how to compare two objects.
Since the sort and search facilities
are general, you have to specify the
* 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.
Pattern Matching
* 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.
* 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'.
Regular Expressions
* 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.
Word Expansion
* 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.
I/O Overview
* I/O Concepts:: Some basic information and terminology.
* File Names:: How to refer to a file.
I/O Concepts
* 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 Names
* Directories:: Directories contain entries for files.
* File Name Resolution:: A file name specifies how to look up a file.
* File Name Errors:: Error conditions relating to file names.
* File Name Portability:: File name portability and syntax issues.
I/O on Streams
* Streams:: About the data type representing a stream.
* Standard Streams:: Streams to the standard input and output
devices are created for you.
* Opening Streams:: How to create a stream to talk to a file.
* Closing Streams:: Close a stream when you are finished with it.
* Streams and Threads:: Issues with streams in threaded programs.
* Streams and I18N:: Streams in internationalized applications.
* Simple Output:: Unformatted output by characters and lines.
* Character Input:: Unformatted input by characters and words.
* Line Input:: Reading a line or a record from a stream.
* Unreading:: Peeking ahead/pushing back input just read.
* Block Input/Output:: Input and output operations on blocks of data.
* Formatted Output:: `printf' and related functions.
* Customizing Printf:: You can define new conversion specifiers for
`printf' and friends.
* Formatted Input:: `scanf' and related functions.
* EOF and Errors:: How you can tell if an I/O error happens.
* Error Recovery:: What you can do about errors.
* Binary Streams:: Some systems distinguish between text files
and binary files.
* File Positioning:: About random-access streams.
* Portable Positioning:: Random access on peculiar ISO C systems.
* Stream Buffering:: How to control buffering of streams.
* Other Kinds of Streams:: Streams that do not necessarily correspond
to an open file.
* Formatted Messages:: Print strictly formatted messages.
* Unreading Idea:: An explanation of unreading with pictures.
* How Unread:: How to call `ungetc' to do unreading.
Formatted Output
* Formatted Output Basics:: Some examples to get you started.
* Output Conversion Syntax:: General syntax of conversion
* Table of Output Conversions:: Summary of output conversions and
what they do.
* Integer Conversions:: Details about formatting of integers.
* Floating-Point Conversions:: Details about formatting of
floating-point numbers.
* Other Output Conversions:: Details about formatting of strings,
characters, pointers, and the like.
* Formatted Output Functions:: Descriptions of the actual functions.
* Dynamic Output:: Functions that allocate memory for the output.
* Variable Arguments Output:: `vprintf' and friends.
* Parsing a Template String:: What kinds of args does a given template
call for?
* Example of Parsing:: Sample program using `parse_printf_format'.
Customizing Printf
* Registering New Conversions:: Using `register_printf_function'
to register a new output conversion.
* Conversion Specifier Options:: The handler must be able to get
the options specified in the
template when it is called.
* Defining the Output Handler:: Defining the handler and arginfo
functions that are passed as arguments
to `register_printf_function'.
* Printf Extension Example:: How to define a `printf'
handler function.
* Predefined Printf Handlers:: Predefined `printf' handlers.
Formatted Input
* Formatted Input Basics:: Some basics to get you started.
* Input Conversion Syntax:: Syntax of conversion specifications.
* Table of Input Conversions:: Summary of input conversions and what they do.
* Numeric Input Conversions:: Details of conversions for reading numbers.
* String Input Conversions:: Details of conversions for reading strings.
* Dynamic String Input:: String conversions that `malloc' the buffer.
* Other Input Conversions:: Details of miscellaneous other conversions.
* Formatted Input Functions:: Descriptions of the actual functions.
* Variable Arguments Input:: `vscanf' and friends.
Stream Buffering
* Buffering Concepts:: Terminology is defined here.
* Flushing Buffers:: How to ensure that output buffers are flushed.
* Controlling Buffering:: How to specify what kind of buffering to use.
Other Kinds of Streams
* String Streams:: Streams that get data from or put data in
a string or memory buffer.
* Custom Streams:: Defining your own streams with an arbitrary
input data source and/or output data sink.
Custom Streams
* Streams and Cookies:: The "cookie" records where to fetch or
store data that is read or written.
* Hook Functions:: How you should define the four "hook
functions" that a custom stream needs.
Formatted Messages
* Printing Formatted Messages:: The `fmtmsg' function.
* Adding Severity Classes:: Add more severity classes.
* Example:: How to use `fmtmsg' and `addseverity'.
Low-Level I/O
* Opening and Closing Files:: How to open and close file
* I/O Primitives:: Reading and writing data.
* File Position Primitive:: Setting a descriptor's file
* Descriptors and Streams:: Converting descriptor to stream
or vice-versa.
* Stream/Descriptor Precautions:: Precautions needed if you use both
descriptors and streams.
* Scatter-Gather:: Fast I/O to discontinuous buffers.
* Memory-mapped I/O:: Using files like memory.
* Waiting for I/O:: How to check for input or output
on multiple file descriptors.
* Synchronizing I/O:: Making sure all I/O actions completed.
* Asynchronous I/O:: Perform I/O in parallel.
* Control Operations:: Various other operations on file
* Duplicating Descriptors:: Fcntl commands for duplicating
file descriptors.
* Descriptor Flags:: Fcntl commands for manipulating
flags associated with file
* File Status Flags:: Fcntl commands for manipulating
flags associated with open files.
* File Locks:: Fcntl commands for implementing
file locking.
* Interrupt Input:: Getting an asynchronous signal when
input arrives.
* IOCTLs:: Generic I/O Control operations.
Stream/Descriptor Precautions
* Linked Channels:: Dealing with channels sharing a file position.
* Independent Channels:: Dealing with separately opened, unlinked channels.
* Cleaning Streams:: Cleaning a stream makes it safe to use
another channel.
Asynchronous I/O
* Asynchronous Reads/Writes:: Asynchronous Read and Write Operations.
* Status of AIO Operations:: Getting the Status of AIO Operations.
* Synchronizing AIO Operations:: Getting into a consistent state.
* Cancel AIO Operations:: Cancellation of AIO Operations.
* Configuration of AIO:: How to optimize the AIO implementation.
File Status Flags
* Access Modes:: Whether the descriptor can read or write.
* Open-time Flags:: Details of `open'.
* Operating Modes:: Special modes to control I/O operations.
* Getting File Status Flags:: Fetching and changing these flags.
File System Interface
* Working Directory:: This is used to resolve relative
file names.
* Accessing Directories:: Finding out what files a directory
* Working with Directory Trees:: Apply actions to all files or a selectable
subset of a directory hierarchy.
* Hard Links:: Adding alternate names to a file.
* Symbolic Links:: A file that ``points to'' a file name.
* Deleting Files:: How to delete a file, and what that means.
* Renaming Files:: Changing a file's name.
* Creating Directories:: A system call just for creating a directory.
* File Attributes:: Attributes of individual files.
* Making Special Files:: How to create special files.
* Temporary Files:: Naming and creating temporary files.
Accessing Directories
* Directory Entries:: Format of one directory entry.
* Opening a Directory:: How to open a directory stream.
* Reading/Closing Directory:: How to read directory entries from the stream.
* Simple Directory Lister:: A very simple directory listing program.
* Random Access Directory:: Rereading part of the directory
already read with the same stream.
* Scanning Directory Content:: Get entries for user selected subset of
contents in given directory.
* Simple Directory Lister Mark II:: Revised version of the program.
File Attributes
* Attribute Meanings:: The names of the file attributes,
and what their values mean.
* Reading Attributes:: How to read the attributes of a file.
* Testing File Type:: Distinguishing ordinary files,
directories, links...
* File Owner:: How ownership for new files is determined,
and how to change it.
* Permission Bits:: How information about a file's access
mode is stored.
* Access Permission:: How the system decides who can access a file.
* Setting Permissions:: How permissions for new files are assigned,
and how to change them.
* Testing File Access:: How to find out if your process can
access a file.
* File Times:: About the time attributes of a file.
* File Size:: Manually changing the size of a file.
Pipes and FIFOs
* Creating a Pipe:: Making a pipe with the `pipe' function.
* Pipe to a Subprocess:: Using a pipe to communicate with a
child process.
* FIFO Special Files:: Making a FIFO special file.
* Pipe Atomicity:: When pipe (or FIFO) I/O is atomic.
* Socket Concepts:: Basic concepts you need to know about.
* Communication Styles::Stream communication, datagrams and other styles.
* Socket Addresses:: How socket names (``addresses'') work.
* Interface Naming:: Identifying specific network interfaces.
* Local Namespace:: Details about the local namespace.
* Internet Namespace:: Details about the Internet namespace.
* Misc Namespaces:: Other namespaces not documented fully here.
* Open/Close Sockets:: Creating sockets and destroying them.
* Connections:: Operations on sockets with connection state.
* Datagrams:: Operations on datagram sockets.
* Inetd:: Inetd is a daemon that starts servers on request.
The most convenient way to write a server
is to make it work with Inetd.
* Socket Options:: Miscellaneous low-level socket options.
* Networks Database:: Accessing the database of network names.
Socket Addresses
* Address Formats:: About `struct sockaddr'.
* Setting Address:: Binding an address to a socket.
* Reading Address:: Reading the address of a socket.
Local Namespace
* Concepts: Local Namespace Concepts. What you need to understand.
* Details: Local Namespace Details. Address format, symbolic names, etc.
* Example: Local Socket Example. Example of creating a socket.
Internet Namespace
* Internet Address Formats:: How socket addresses are specified in the
Internet namespace.
* Host Addresses:: All about host addresses of Internet host.
* Ports:: Internet port numbers.
* Services Database:: Ports may have symbolic names.
* Byte Order:: Different hosts may use different byte
ordering conventions; you need to
canonicalize host address and port number.
* Protocols Database:: Referring to protocols by name.
* Inet Example:: Putting it all together.
Host Addresses
* Abstract Host Addresses:: What a host number consists of.
* Data type: Host Address Data Type. Data type for a host number.
* Functions: Host Address Functions. Functions to operate on them.
* Names: Host Names. Translating host names to host numbers.
Open/Close Sockets
* Creating a Socket:: How to open a socket.
* Closing a Socket:: How to close a socket.
* Socket Pairs:: These are created like pipes.
* Connecting:: What the client program must do.
* Listening:: How a server program waits for requests.
* Accepting Connections:: What the server does when it gets a request.
* Who is Connected:: Getting the address of the
other side of a connection.
* Transferring Data:: How to send and receive data.
* Byte Stream Example:: An example program: a client for communicating
over a byte stream socket in the Internet namespace.
* Server Example:: A corresponding server program.
* Out-of-Band Data:: This is an advanced feature.
Transferring Data
* Sending Data:: Sending data with `send'.
* Receiving Data:: Reading data with `recv'.
* Socket Data Options:: Using `send' and `recv'.
* Sending Datagrams:: Sending packets on a datagram socket.
* Receiving Datagrams:: Receiving packets on a datagram socket.
* Datagram Example:: An example program: packets sent over a
datagram socket in the local namespace.
* Example Receiver:: Another program, that receives those packets.
* Inetd Servers::
* Configuring Inetd::
Socket Options
* Socket Option Functions:: The basic functions for setting and getting
socket options.
* Socket-Level Options:: Details of the options at the socket level.
Low-Level Terminal Interface
* Is It a Terminal:: How to determine if a file is a terminal
device, and what its name is.
* I/O Queues:: About flow control and typeahead.
* Canonical or Not:: Two basic styles of input processing.
* Terminal Modes:: How to examine and modify flags controlling
details of terminal I/O: echoing,
signals, editing. Posix.
* BSD Terminal Modes:: BSD compatible terminal mode setting
* Line Control:: Sending break sequences, clearing
terminal buffers ...
* Noncanon Example:: How to read single characters without echo.
* Pseudo-Terminals:: How to open a pseudo-terminal.
Terminal Modes
* Mode Data Types:: The data type `struct termios' and
related types.
* Mode Functions:: Functions to read and set the terminal
* Setting Modes:: The right way to set terminal attributes
* Input Modes:: Flags controlling low-level input handling.
* Output Modes:: Flags controlling low-level output handling.
* Control Modes:: Flags controlling serial port behavior.
* Local Modes:: Flags controlling high-level input handling.
* Line Speed:: How to read and set the terminal line speed.
* Special Characters:: Characters that have special effects,
and how to change them.
* Noncanonical Input:: Controlling how long to wait for input.
Special Characters
* Editing Characters:: Special characters that terminate lines and
delete text, and other editing functions.
* Signal Characters:: Special characters that send or raise signals
to or for certain classes of processes.
* Start/Stop Characters:: Special characters that suspend or resume
suspended output.
* Other Special:: Other special characters for BSD systems:
they can discard output, and print status.
* Allocation:: Allocating a pseudo terminal.
* Pseudo-Terminal Pairs:: How to open both sides of a
pseudo-terminal in a single operation.
* Overview of Syslog:: Overview of a system's Syslog facility
* Submitting Syslog Messages:: Functions to submit messages to Syslog
Submitting Syslog Messages
* openlog:: Open connection to Syslog
* syslog; vsyslog:: Submit message to Syslog
* closelog:: Close connection to Syslog
* setlogmask:: Cause certain messages to be ignored
* Syslog Example:: Example of all of the above
* Mathematical Constants:: Precise numeric values for often-used
* Trig Functions:: Sine, cosine, tangent, and friends.
* Inverse Trig Functions:: Arcsine, arccosine, etc.
* Exponents and Logarithms:: Also pow and sqrt.
* Hyperbolic Functions:: sinh, cosh, tanh, etc.
* Special Functions:: Bessel, gamma, erf.
* Errors in Math Functions:: Known Maximum Errors in Math Functions.
* Pseudo-Random Numbers:: Functions for generating pseudo-random
* FP Function Optimizations:: Fast code or small code.
Pseudo-Random Numbers
* ISO Random:: `rand' and friends.
* BSD Random:: `random' and friends.
* SVID Random:: `drand48' and friends.
* Integers:: Basic integer types and concepts
* Integer Division:: Integer division with guaranteed rounding.
* Floating Point Numbers:: Basic concepts. IEEE 754.
* Floating Point Classes:: The five kinds of floating-point number.
* Floating Point Errors:: When something goes wrong in a calculation.
* Rounding:: Controlling how results are rounded.
* Control Functions:: Saving and restoring the FPU's state.
* Arithmetic Functions:: Fundamental operations provided by the library.
* Complex Numbers:: The types. Writing complex constants.
* Operations on Complex:: Projection, conjugation, decomposition.
* Parsing of Numbers:: Converting strings to numbers.
* System V Number Conversion:: An archaic way to convert numbers to strings.
Floating Point Errors
* FP Exceptions:: IEEE 754 math exceptions and how to detect them.
* Infinity and NaN:: Special values returned by calculations.
* Status bit operations:: Checking for exceptions after the fact.
* Math Error Reporting:: How the math functions report errors.
Arithmetic Functions
* Absolute Value:: Absolute values of integers and floats.
* Normalization Functions:: Extracting exponents and putting them back.
* Rounding Functions:: Rounding floats to integers.
* Remainder Functions:: Remainders on division, precisely defined.
* FP Bit Twiddling:: Sign bit adjustment. Adding epsilon.
* FP Comparison Functions:: Comparisons without risk of exceptions.
* Misc FP Arithmetic:: Max, min, positive difference, multiply-add.
Parsing of Numbers
* Parsing of Integers:: Functions for conversion of integer values.
* Parsing of Floats:: Functions for conversion of floating-point
Date and Time
* Time Basics:: Concepts and definitions.
* Elapsed Time:: Data types to represent elapsed times
* Processor And CPU Time:: Time a program has spent executing.
* Calendar Time:: Manipulation of ``real'' dates and times.
* Setting an Alarm:: Sending a signal after a specified time.
* Sleeping:: Waiting for a period of time.
Processor And CPU Time
* CPU Time:: The `clock' function.
* Processor Time:: The `times' function.
Calendar Time
* Simple Calendar Time:: Facilities for manipulating calendar time.
* High-Resolution Calendar:: A time representation with greater precision.
* Broken-down Time:: Facilities for manipulating local time.
* High Accuracy Clock:: Maintaining a high accuracy system clock.
* Formatting Calendar Time:: Converting times to strings.
* Parsing Date and Time:: Convert textual time and date information back
into broken-down time values.
* TZ Variable:: How users specify the time zone.
* Time Zone Functions:: Functions to examine or specify the time zone.
* Time Functions Example:: An example program showing use of some of
the time functions.
Parsing Date and Time
* Low-Level Time String Parsing:: Interpret string according to given format.
* General Time String Parsing:: User-friendly function to parse data and
time strings.
Resource Usage And Limitation
* Resource Usage:: Measuring various resources used.
* Limits on Resources:: Specifying limits on resource usage.
* Priority:: Reading or setting process run priority.
* Memory Resources:: Querying memory available resources.
* Processor Resources:: Learn about the processors available.
* Absolute Priority:: The first tier of priority. Posix
* Realtime Scheduling:: Scheduling among the process nobility
* Basic Scheduling Functions:: Get/set scheduling policy, priority
* Traditional Scheduling:: Scheduling among the vulgar masses
* CPU Affinity:: Limiting execution to certain CPUs
Traditional Scheduling
* Traditional Scheduling Intro::
* Traditional Scheduling Functions::
Memory Resources
* Memory Subsystem:: Overview about traditional Unix memory handling.
* Query Memory Parameters:: How to get information about the memory
Non-Local Exits
* Intro: Non-Local Intro. When and how to use these facilities.
* Details: Non-Local Details. Functions for non-local exits.
* Non-Local Exits and Signals:: Portability issues.
* System V contexts:: Complete context control a la System V.
Signal Handling
* Concepts of Signals:: Introduction to the signal facilities.
* Standard Signals:: Particular kinds of signals with
standard names and meanings.
* Signal Actions:: Specifying what happens when a
particular signal is delivered.
* Defining Handlers:: How to write a signal handler function.
* Interrupted Primitives:: Signal handlers affect use of `open',
`read', `write' and other functions.
* Generating Signals:: How to send a signal to a process.
* Blocking Signals:: Making the system hold signals temporarily.
* Waiting for a Signal:: Suspending your program until a signal
* Signal Stack:: Using a Separate Signal Stack.
* BSD Signal Handling:: Additional functions for backward
compatibility with BSD.
Concepts of Signals
* Kinds of Signals:: Some examples of what can cause a signal.
* Signal Generation:: Concepts of why and how signals occur.
* Delivery of Signal:: Concepts of what a signal does to the
Standard Signals
* Program Error Signals:: Used to report serious program errors.
* Termination Signals:: Used to interrupt and/or terminate the
* Alarm Signals:: Used to indicate expiration of timers.
* Asynchronous I/O Signals:: Used to indicate input is available.
* Job Control Signals:: Signals used to support job control.
* Operation Error Signals:: Used to report operational system errors.
* Miscellaneous Signals:: Miscellaneous Signals.
* Signal Messages:: Printing a message describing a signal.
Signal Actions
* Basic Signal Handling:: The simple `signal' function.
* Advanced Signal Handling:: The more powerful `sigaction' function.
* Signal and Sigaction:: How those two functions interact.
* Sigaction Function Example:: An example of using the sigaction function.
* Flags for Sigaction:: Specifying options for signal handling.
* Initial Signal Actions:: How programs inherit signal actions.
Defining Handlers
* Handler Returns:: Handlers that return normally, and what
this means.
* Termination in Handler:: How handler functions terminate a program.
* Longjmp in Handler:: Nonlocal transfer of control out of a
signal handler.
* Signals in Handler:: What happens when signals arrive while
the handler is already occupied.
* Merged Signals:: When a second signal arrives before the
first is handled.
* Nonreentrancy:: Do not call any functions unless you know they
are reentrant with respect to signals.
* Atomic Data Access:: A single handler can run in the middle of
reading or writing a single object.
Atomic Data Access
* Non-atomic Example:: A program illustrating interrupted access.
* Types: Atomic Types. Data types that guarantee no interruption.
* Usage: Atomic Usage. Proving that interruption is harmless.
Generating Signals
* Signaling Yourself:: A process can send a signal to itself.
* Signaling Another Process:: Send a signal to another process.
* Permission for kill:: Permission for using `kill'.
* Kill Example:: Using `kill' for Communication.
Blocking Signals
* Why Block:: The purpose of blocking signals.
* Signal Sets:: How to specify which signals to
* Process Signal Mask:: Blocking delivery of signals to your
process during normal execution.
* Testing for Delivery:: Blocking to Test for Delivery of
a Signal.
* Blocking for Handler:: Blocking additional signals while a
handler is being run.
* Checking for Pending Signals:: Checking for Pending Signals
* Remembering a Signal:: How you can get almost the same
effect as blocking a signal, by
handling it and setting a flag
to be tested later.
Waiting for a Signal
* Using Pause:: The simple way, using `pause'.
* Pause Problems:: Why the simple way is often not very good.
* Sigsuspend:: Reliably waiting for a specific signal.
BSD Signal Handling
* BSD Handler:: BSD Function to Establish a Handler.
* Blocking in BSD:: BSD Functions for Blocking Signals.
Program Basics
* Program Arguments:: Parsing your program's command-line arguments
* Environment Variables:: Less direct parameters affecting your program
* Auxiliary Vector:: Least direct parameters affecting your program
* System Calls:: Requesting service from the system
* Program Termination:: Telling the system you're done; return status
Program Arguments
* Argument Syntax:: By convention, options start with a hyphen.
* Parsing Program Arguments:: Ways to parse program options and arguments.
Parsing Program Arguments
* Getopt:: Parsing program options using `getopt'.
* Argp:: Parsing program options using `argp_parse'.
* Suboptions:: Some programs need more detailed options.
* Suboptions Example:: This shows how it could be done for `mount'.
Environment Variables
* Environment Access:: How to get and set the values of
environment variables.
* Standard Environment:: These environment variables have
standard interpretations.
Program Termination
* Normal Termination:: If a program calls `exit', a
process terminates normally.
* Exit Status:: The `exit status' provides information
about why the process terminated.
* Cleanups on Exit:: A process can run its own cleanup
functions upon normal termination.
* Aborting a Program:: The `abort' function causes
abnormal program termination.
* Termination Internals:: What happens when a process terminates.
* Running a Command:: The easy way to run another program.
* Process Creation Concepts:: An overview of the hard way to do it.
* Process Identification:: How to get the process ID of a process.
* Creating a Process:: How to fork a child process.
* Executing a File:: How to make a process execute another program.
* Process Completion:: How to tell when a child process has completed.
* Process Completion Status:: How to interpret the status value
returned from a child process.
* BSD Wait Functions:: More functions, for backward compatibility.
* Process Creation Example:: A complete example program.
Job Control
* Concepts of Job Control:: Jobs can be controlled by a shell.
* Job Control is Optional:: Not all POSIX systems support job control.
* Controlling Terminal:: How a process gets its controlling terminal.
* Access to the Terminal:: How processes share the controlling terminal.
* Orphaned Process Groups:: Jobs left after the user logs out.
* Implementing a Shell:: What a shell must do to implement job control.
* Functions for Job Control:: Functions to control process groups.
Implementing a Shell
* Data Structures:: Introduction to the sample shell.
* Initializing the Shell:: What the shell must do to take
responsibility for job control.
* Launching Jobs:: Creating jobs to execute commands.
* Foreground and Background:: Putting a job in foreground of background.
* Stopped and Terminated Jobs:: Reporting job status.
* Continuing Stopped Jobs:: How to continue a stopped job in
the foreground or background.
* Missing Pieces:: Other parts of the shell.
Functions for Job Control
* Identifying the Terminal:: Determining the controlling terminal's name.
* Process Group Functions:: Functions for manipulating process groups.
* Terminal Access Functions:: Functions for controlling terminal access.
Name Service Switch
* NSS Basics:: What is this NSS good for.
* NSS Configuration File:: Configuring NSS.
* NSS Module Internals:: How does it work internally.
* Extending NSS:: What to do to add services or databases.
NSS Configuration File
* Services in the NSS configuration:: Service names in the NSS configuration.
* Actions in the NSS configuration:: React appropriately to the lookup result.
* Notes on NSS Configuration File:: Things to take care about while
configuring NSS.
NSS Module Internals
* NSS Module Names:: Construction of the interface function of
the NSS modules.
* NSS Modules Interface:: Programming interface in the NSS module
Extending NSS
* Adding another Service to NSS:: What is to do to add a new service.
* NSS Module Function Internals:: Guidelines for writing new NSS
service functions.
Users and Groups
* User and Group IDs:: Each user has a unique numeric ID;
likewise for groups.
* Process Persona:: The user IDs and group IDs of a process.
* Why Change Persona:: Why a program might need to change
its user and/or group IDs.
* How Change Persona:: Changing the user and group IDs.
* Reading Persona:: How to examine the user and group IDs.
* Setting User ID:: Functions for setting the user ID.
* Setting Groups:: Functions for setting the group IDs.
* Enable/Disable Setuid:: Turning setuid access on and off.
* Setuid Program Example:: The pertinent parts of one sample program.
* Tips for Setuid:: How to avoid granting unlimited access.
* Who Logged In:: Getting the name of the user who logged in,
or of the real user ID of the current process.
* User Accounting Database:: Keeping information about users and various
actions in databases.
* User Database:: Functions and data structures for
accessing the user database.
* Group Database:: Functions and data structures for
accessing the group database.
* Database Example:: Example program showing the use of database
inquiry functions.
* Netgroup Database:: Functions for accessing the netgroup database.
User Accounting Database
* Manipulating the Database:: Scanning and modifying the user
accounting database.
* XPG Functions:: A standardized way for doing the same thing.
* Logging In and Out:: Functions from BSD that modify the user
accounting database.
User Database
* User Data Structure:: What each user record contains.
* Lookup User:: How to look for a particular user.
* Scanning All Users:: Scanning the list of all users, one by one.
* Writing a User Entry:: How a program can rewrite a user's record.
Group Database
* Group Data Structure:: What each group record contains.
* Lookup Group:: How to look for a particular group.
* Scanning All Groups:: Scanning the list of all groups.
Netgroup Database
* Netgroup Data:: Data in the Netgroup database and where
it comes from.
* Lookup Netgroup:: How to look for a particular netgroup.
* Netgroup Membership:: How to test for netgroup membership.
System Management
* Host Identification:: Determining the name of the machine.
* Platform Type:: Determining operating system and basic
machine type
* Filesystem Handling:: Controlling/querying mounts
* System Parameters:: Getting and setting various system parameters
Filesystem Handling
* Mount Information:: What is or could be mounted?
* Mount-Unmount-Remount:: Controlling what is mounted and how
Mount Information
* fstab:: The `fstab' file
* mtab:: The `mtab' file
* Other Mount Information:: Other (non-libc) sources of mount information
System Configuration
* General Limits:: Constants and functions that describe
various process-related limits that have
one uniform value for any given machine.
* System Options:: Optional POSIX features.
* Version Supported:: Version numbers of POSIX.1 and POSIX.2.
* Sysconf:: Getting specific configuration values
of general limits and system options.
* Minimums:: Minimum values for general limits.
* Limits for Files:: Size limitations that pertain to individual files.
These can vary between file systems
or even from file to file.
* Options for Files:: Optional features that some files may support.
* File Minimums:: Minimum values for file limits.
* Pathconf:: Getting the limit values for a particular file.
* Utility Limits:: Capacity limits of some POSIX.2 utility programs.
* Utility Minimums:: Minimum allowable values of those limits.
* String Parameters:: Getting the default search path.
* Sysconf Definition:: Detailed specifications of `sysconf'.
* Constants for Sysconf:: The list of parameters `sysconf' can read.
* Examples of Sysconf:: How to use `sysconf' and the parameter
macros properly together.
Cryptographic Functions
* Legal Problems:: This software can get you locked up, or worse.
* getpass:: Prompting the user for a password.
* crypt:: A one-way function for passwords.
* DES Encryption:: Routines for DES encryption.
Debugging Support
* Backtraces:: Obtaining and printing a back trace of the
current stack.
POSIX Threads
* Thread-specific Data:: Support for creating and
managing thread-specific data
* Non-POSIX Extensions:: Additional functions to extend
POSIX Thread functionality
Non-POSIX Extensions
* Default Thread Attributes:: Setting default attributes for
threads in a process.
Language Features
* Consistency Checking:: Using `assert' to abort if
something ``impossible'' happens.
* Variadic Functions:: Defining functions with varying numbers
of args.
* Null Pointer Constant:: The macro `NULL'.
* Important Data Types:: Data types for object sizes.
* Data Type Measurements:: Parameters of data type representations.
Variadic Functions
* Why Variadic:: Reasons for making functions take
variable arguments.
* How Variadic:: How to define and call variadic functions.
* Variadic Example:: A complete example.
How Variadic
* Variadic Prototypes:: How to make a prototype for a function
with variable arguments.
* Receiving Arguments:: Steps you must follow to access the
optional argument values.
* How Many Arguments:: How to decide whether there are more arguments.
* Calling Variadics:: Things you need to know about calling
variable arguments functions.
* Argument Macros:: Detailed specification of the macros
for accessing variable arguments.
Data Type Measurements
* Width of Type:: How many bits does an integer type hold?
* Range of Type:: What are the largest and smallest values
that an integer type can hold?
* Floating Type Macros:: Parameters that measure the floating point types.
* Structure Measurement:: Getting measurements on structure types.
Floating Type Macros
* Floating Point Concepts:: Definitions of terminology.
* Floating Point Parameters:: Details of specific macros.
* IEEE Floating Point:: The measurements for one common
* Configuring and compiling:: How to compile and test GNU libc.
* Running make install:: How to install it once you've got it
* Tools for Compilation:: You'll need these first.
* Linux:: Specific advice for GNU/Linux systems.
* Reporting Bugs:: So they'll get fixed.
* Source Layout:: How to add new functions or header files
to the GNU C Library.
* Porting:: How to port the GNU C Library to
a new machine or operating system.
Source Layout
* Platform: Adding Platform-specific. Adding platform-specific
* Hierarchy Conventions:: The layout of the `sysdeps' hierarchy.
* Porting to Unix:: Porting the library to an average
Unix-like system.
* PowerPC:: Facilities Specific to the PowerPC Architecture

File:, Node: Introduction, Next: Error Reporting, Prev: Top, Up: Top
1 Introduction
The C language provides no built-in facilities for performing such
common operations as input/output, memory management, string
manipulation, and the like. Instead, these facilities are defined in a
standard "library", which you compile and link with your programs.
The GNU C Library, described in this document, defines all of the
library functions that are specified by the ISO C standard, as well as
additional features specific to POSIX and other derivatives of the Unix
operating system, and extensions specific to GNU systems.
The purpose of this manual is to tell you how to use the facilities
of the GNU C Library. We have mentioned which features belong to which
standards to help you identify things that are potentially non-portable
to other systems. But the emphasis in this manual is not on strict
* Menu:
* Getting Started:: What this manual is for and how to use it.
* Standards and Portability:: Standards and sources upon which the GNU
C library is based.
* Using the Library:: Some practical uses for the library.
* Roadmap to the Manual:: Overview of the remaining chapters in
this manual.

File:, Node: Getting Started, Next: Standards and Portability, Up: Introduction
1.1 Getting Started
This manual is written with the assumption that you are at least
somewhat familiar with the C programming language and basic programming
concepts. Specifically, familiarity with ISO standard C (*note ISO
C::), rather than "traditional" pre-ISO C dialects, is assumed.
The GNU C Library includes several "header files", each of which
provides definitions and declarations for a group of related facilities;
this information is used by the C compiler when processing your program.
For example, the header file `stdio.h' declares facilities for
performing input and output, and the header file `string.h' declares
string processing utilities. The organization of this manual generally
follows the same division as the header files.
If you are reading this manual for the first time, you should read
all of the introductory material and skim the remaining chapters.
There are a _lot_ of functions in the GNU C Library and it's not
realistic to expect that you will be able to remember exactly _how_ to
use each and every one of them. It's more important to become
generally familiar with the kinds of facilities that the library
provides, so that when you are writing your programs you can recognize
_when_ to make use of library functions, and _where_ in this manual you
can find more specific information about them.

File:, Node: Standards and Portability, Next: Using the Library, Prev: Getting Started, Up: Introduction
1.2 Standards and Portability
This section discusses the various standards and other sources that the
GNU C Library is based upon. These sources include the ISO C and POSIX
standards, and the System V and Berkeley Unix implementations.
The primary focus of this manual is to tell you how to make effective
use of the GNU C Library facilities. But if you are concerned about
making your programs compatible with these standards, or portable to
operating systems other than GNU, this can affect how you use the
library. This section gives you an overview of these standards, so that
you will know what they are when they are mentioned in other parts of
the manual.
*Note Library Summary::, for an alphabetical list of the functions
and other symbols provided by the library. This list also states which
standards each function or symbol comes from.
* Menu:
* ISO C:: The international standard for the C
programming language.
* POSIX:: The ISO/IEC 9945 (aka IEEE 1003) standards
for operating systems.
* Berkeley Unix:: BSD and SunOS.
* SVID:: The System V Interface Description.
* XPG:: The X/Open Portability Guide.

File:, Node: ISO C, Next: POSIX, Up: Standards and Portability
1.2.1 ISO C
The GNU C Library is compatible with the C standard adopted by the
American National Standards Institute (ANSI): `American National
Standard X3.159-1989--"ANSI C"' and later by the International
Standardization Organization (ISO): `ISO/IEC 9899:1990, "Programming
languages--C"'. We here refer to the standard as ISO C since this is
the more general standard in respect of ratification. The header files
and library facilities that make up the GNU C Library are a superset of
those specified by the ISO C standard.
If you are concerned about strict adherence to the ISO C standard,
you should use the `-ansi' option when you compile your programs with
the GNU C compiler. This tells the compiler to define _only_ ISO
standard features from the library header files, unless you explicitly
ask for additional features. *Note Feature Test Macros::, for
information on how to do this.
Being able to restrict the library to include only ISO C features is
important because ISO C puts limitations on what names can be defined
by the library implementation, and the GNU extensions don't fit these
limitations. *Note Reserved Names::, for more information about these
This manual does not attempt to give you complete details on the
differences between ISO C and older dialects. It gives advice on how
to write programs to work portably under multiple C dialects, but does
not aim for completeness.

File:, Node: POSIX, Next: Berkeley Unix, Prev: ISO C, Up: Standards and Portability
1.2.2 POSIX (The Portable Operating System Interface)
The GNU C Library is also compatible with the ISO "POSIX" family of
standards, known more formally as the "Portable Operating System
Interface for Computer Environments" (ISO/IEC 9945). They were also
published as ANSI/IEEE Std 1003. POSIX is derived mostly from various
versions of the Unix operating system.
The library facilities specified by the POSIX standards are a
superset of those required by ISO C; POSIX specifies additional
features for ISO C functions, as well as specifying new additional
functions. In general, the additional requirements and functionality
defined by the POSIX standards are aimed at providing lower-level
support for a particular kind of operating system environment, rather
than general programming language support which can run in many diverse
operating system environments.
The GNU C Library implements all of the functions specified in
`ISO/IEC 9945-1:1996, the POSIX System Application Program Interface',
commonly referred to as POSIX.1. The primary extensions to the ISO C
facilities specified by this standard include file system interface
primitives (*note File System Interface::), device-specific terminal
control functions (*note Low-Level Terminal Interface::), and process
control functions (*note Processes::).
Some facilities from `ISO/IEC 9945-2:1993, the POSIX Shell and
Utilities standard' (POSIX.2) are also implemented in the GNU C Library.
These include utilities for dealing with regular expressions and other
pattern matching facilities (*note Pattern Matching::).

File:, Node: Berkeley Unix, Next: SVID, Prev: POSIX, Up: Standards and Portability
1.2.3 Berkeley Unix
The GNU C Library defines facilities from some versions of Unix which
are not formally standardized, specifically from the 4.2 BSD, 4.3 BSD,
and 4.4 BSD Unix systems (also known as "Berkeley Unix") and from
"SunOS" (a popular 4.2 BSD derivative that includes some Unix System V
functionality). These systems support most of the ISO C and POSIX
facilities, and 4.4 BSD and newer releases of SunOS in fact support
them all.
The BSD facilities include symbolic links (*note Symbolic Links::),
the `select' function (*note Waiting for I/O::), the BSD signal
functions (*note BSD Signal Handling::), and sockets (*note Sockets::).

File:, Node: SVID, Next: XPG, Prev: Berkeley Unix, Up: Standards and Portability
1.2.4 SVID (The System V Interface Description)
The "System V Interface Description" (SVID) is a document describing
the AT&T Unix System V operating system. It is to some extent a
superset of the POSIX standard (*note POSIX::).
The GNU C Library defines most of the facilities required by the SVID
that are not also required by the ISO C or POSIX standards, for
compatibility with System V Unix and other Unix systems (such as
SunOS) which include these facilities. However, many of the more
obscure and less generally useful facilities required by the SVID are
not included. (In fact, Unix System V itself does not provide them
The supported facilities from System V include the methods for
inter-process communication and shared memory, the `hsearch' and
`drand48' families of functions, `fmtmsg' and several of the
mathematical functions.

File:, Node: XPG, Prev: SVID, Up: Standards and Portability
1.2.5 XPG (The X/Open Portability Guide)
The X/Open Portability Guide, published by the X/Open Company, Ltd., is
a more general standard than POSIX. X/Open owns the Unix copyright and
the XPG specifies the requirements for systems which are intended to be
a Unix system.
The GNU C Library complies to the X/Open Portability Guide, Issue
4.2, with all extensions common to XSI (X/Open System Interface)
compliant systems and also all X/Open UNIX extensions.
The additions on top of POSIX are mainly derived from functionality
available in System V and BSD systems. Some of the really bad mistakes
in System V systems were corrected, though. Since fulfilling the XPG
standard with the Unix extensions is a precondition for getting the
Unix brand chances are good that the functionality is available on
commercial systems.

File:, Node: Using the Library, Next: Roadmap to the Manual, Prev: Standards and Portability, Up: Introduction
1.3 Using the Library
This section describes some of the practical issues involved in using
the GNU C Library.
* Menu:
* Header Files:: How to include the header files in your
* Macro Definitions:: Some functions in the library may really
be implemented as macros.
* Reserved Names:: The C standard reserves some names for
the library, and some for users.
* Feature Test Macros:: How to control what names are defined.

File:, Node: Header Files, Next: Macro Definitions, Up: Using the Library
1.3.1 Header Files
Libraries for use by C programs really consist of two parts: "header
files" that define types and macros and declare variables and
functions; and the actual library or "archive" that contains the
definitions of the variables and functions.
(Recall that in C, a "declaration" merely provides information that
a function or variable exists and gives its type. For a function
declaration, information about the types of its arguments might be
provided as well. The purpose of declarations is to allow the compiler
to correctly process references to the declared variables and functions.
A "definition", on the other hand, actually allocates storage for a
variable or says what a function does.)
In order to use the facilities in the GNU C Library, you should be
sure that your program source files include the appropriate header
files. This is so that the compiler has declarations of these
facilities available and can correctly process references to them.
Once your program has been compiled, the linker resolves these
references to the actual definitions provided in the archive file.
Header files are included into a program source file by the
`#include' preprocessor directive. The C language supports two forms
of this directive; the first,
#include "HEADER"
is typically used to include a header file HEADER that you write
yourself; this would contain definitions and declarations describing the
interfaces between the different parts of your particular application.
By contrast,
#include <file.h>
is typically used to include a header file `file.h' that contains
definitions and declarations for a standard library. This file would
normally be installed in a standard place by your system administrator.
You should use this second form for the C library header files.
Typically, `#include' directives are placed at the top of the C
source file, before any other code. If you begin your source files with
some comments explaining what the code in the file does (a good idea),
put the `#include' directives immediately afterwards, following the
feature test macro definition (*note Feature Test Macros::).
For more information about the use of header files and `#include'
directives, *note Header Files: ( Files.
The GNU C Library provides several header files, each of which
contains the type and macro definitions and variable and function
declarations for a group of related facilities. This means that your
programs may need to include several header files, depending on exactly
which facilities you are using.
Some library header files include other library header files
automatically. However, as a matter of programming style, you should
not rely on this; it is better to explicitly include all the header
files required for the library facilities you are using. The GNU C
Library header files have been written in such a way that it doesn't
matter if a header file is accidentally included more than once;
including a header file a second time has no effect. Likewise, if your
program needs to include multiple header files, the order in which they
are included doesn't matter.
*Compatibility Note:* Inclusion of standard header files in any
order and any number of times works in any ISO C implementation.
However, this has traditionally not been the case in many older C
Strictly speaking, you don't _have to_ include a header file to use
a function it declares; you could declare the function explicitly
yourself, according to the specifications in this manual. But it is
usually better to include the header file because it may define types
and macros that are not otherwise available and because it may define
more efficient macro replacements for some functions. It is also a sure
way to have the correct declaration.

File:, Node: Macro Definitions, Next: Reserved Names, Prev: Header Files, Up: Using the Library
1.3.2 Macro Definitions of Functions
If we describe something as a function in this manual, it may have a
macro definition as well. This normally has no effect on how your
program runs--the macro definition does the same thing as the function
would. In particular, macro equivalents for library functions evaluate
arguments exactly once, in the same way that a function call would. The
main reason for these macro definitions is that sometimes they can
produce an inline expansion that is considerably faster than an actual
function call.
Taking the address of a library function works even if it is also
defined as a macro. This is because, in this context, the name of the
function isn't followed by the left parenthesis that is syntactically
necessary to recognize a macro call.
You might occasionally want to avoid using the macro definition of a
function--perhaps to make your program easier to debug. There are two
ways you can do this:
* You can avoid a macro definition in a specific use by enclosing
the name of the function in parentheses. This works because the
name of the function doesn't appear in a syntactic context where
it is recognizable as a macro call.
* You can suppress any macro definition for a whole source file by
using the `#undef' preprocessor directive, unless otherwise stated
explicitly in the description of that facility.
For example, suppose the header file `stdlib.h' declares a function
named `abs' with
extern int abs (int);
and also provides a macro definition for `abs'. Then, in:
#include <stdlib.h>
int f (int *i) { return abs (++*i); }
the reference to `abs' might refer to either a macro or a function. On
the other hand, in each of the following examples the reference is to a
function and not a macro.
#include <stdlib.h>
int g (int *i) { return (abs) (++*i); }
#undef abs
int h (int *i) { return abs (++*i); }
Since macro definitions that double for a function behave in exactly
the same way as the actual function version, there is usually no need
for any of these methods. In fact, removing macro definitions usually
just makes your program slower.

File:, Node: Reserved Names, Next: Feature Test Macros, Prev: Macro Definitions, Up: Using the Library
1.3.3 Reserved Names
The names of all library types, macros, variables and functions that
come from the ISO C standard are reserved unconditionally; your program
*may not* redefine these names. All other library names are reserved
if your program explicitly includes the header file that defines or
declares them. There are several reasons for these restrictions:
* Other people reading your code could get very confused if you were
using a function named `exit' to do something completely different
from what the standard `exit' function does, for example.
Preventing this situation helps to make your programs easier to
understand and contributes to modularity and maintainability.
* It avoids the possibility of a user accidentally redefining a
library function that is called by other library functions. If
redefinition were allowed, those other functions would not work
* It allows the compiler to do whatever special optimizations it
pleases on calls to these functions, without the possibility that
they may have been redefined by the user. Some library
facilities, such as those for dealing with variadic arguments
(*note Variadic Functions::) and non-local exits (*note Non-Local
Exits::), actually require a considerable amount of cooperation on
the part of the C compiler, and with respect to the
implementation, it might be easier for the compiler to treat these
as built-in parts of the language.
In addition to the names documented in this manual, reserved names
include all external identifiers (global functions and variables) that
begin with an underscore (`_') and all identifiers regardless of use
that begin with either two underscores or an underscore followed by a
capital letter are reserved names. This is so that the library and
header files can define functions, variables, and macros for internal
purposes without risk of conflict with names in user programs.
Some additional classes of identifier names are reserved for future
extensions to the C language or the POSIX.1 environment. While using
these names for your own purposes right now might not cause a problem,
they do raise the possibility of conflict with future versions of the C
or POSIX standards, so you should avoid these names.
* Names beginning with a capital `E' followed a digit or uppercase
letter may be used for additional error code names. *Note Error
* Names that begin with either `is' or `to' followed by a lowercase
letter may be used for additional character testing and conversion
functions. *Note Character Handling::.
* Names that begin with `LC_' followed by an uppercase letter may be
used for additional macros specifying locale attributes. *Note
* Names of all existing mathematics functions (*note Mathematics::)
suffixed with `f' or `l' are reserved for corresponding functions
that operate on `float' and `long double' arguments, respectively.
* Names that begin with `SIG' followed by an uppercase letter are
reserved for additional signal names. *Note Standard Signals::.
* Names that begin with `SIG_' followed by an uppercase letter are
reserved for additional signal actions. *Note Basic Signal
* Names beginning with `str', `mem', or `wcs' followed by a
lowercase letter are reserved for additional string and array
functions. *Note String and Array Utilities::.
* Names that end with `_t' are reserved for additional type names.
In addition, some individual header files reserve names beyond those
that they actually define. You only need to worry about these
restrictions if your program includes that particular header file.
* The header file `dirent.h' reserves names prefixed with `d_'.
* The header file `fcntl.h' reserves names prefixed with `l_', `F_',
`O_', and `S_'.
* The header file `grp.h' reserves names prefixed with `gr_'.
* The header file `limits.h' reserves names suffixed with `_MAX'.
* The header file `pwd.h' reserves names prefixed with `pw_'.
* The header file `signal.h' reserves names prefixed with `sa_' and
* The header file `sys/stat.h' reserves names prefixed with `st_'
and `S_'.
* The header file `sys/times.h' reserves names prefixed with `tms_'.
* The header file `termios.h' reserves names prefixed with `c_',
`V', `I', `O', and `TC'; and names prefixed with `B' followed by a

File:, Node: Feature Test Macros, Prev: Reserved Names, Up: Using the Library
1.3.4 Feature Test Macros
The exact set of features available when you compile a source file is
controlled by which "feature test macros" you define.
If you compile your programs using `gcc -ansi', you get only the
ISO C library features, unless you explicitly request additional
features by defining one or more of the feature macros. *Note GNU CC
Command Options: ( GCC, for more information about GCC
You should define these macros by using `#define' preprocessor
directives at the top of your source code files. These directives
_must_ come before any `#include' of a system header file. It is best
to make them the very first thing in the file, preceded only by
comments. You could also use the `-D' option to GCC, but it's better
if you make the source files indicate their own meaning in a
self-contained way.
This system exists to allow the library to conform to multiple
standards. Although the different standards are often described as
supersets of each other, they are usually incompatible because larger
standards require functions with names that smaller ones reserve to the
user program. This is not mere pedantry -- it has been a problem in
practice. For instance, some non-GNU programs define functions named
`getline' that have nothing to do with this library's `getline'. They
would not be compilable if all features were enabled indiscriminately.
This should not be used to verify that a program conforms to a
limited standard. It is insufficient for this purpose, as it will not
protect you from including header files outside the standard, or
relying on semantics undefined within the standard.
If you define this macro, then the functionality from the POSIX.1
standard (IEEE Standard 1003.1) is available, as well as all of the
ISO C facilities.
The state of `_POSIX_SOURCE' is irrelevant if you define the macro
`_POSIX_C_SOURCE' to a positive integer.
Define this macro to a positive integer to control which POSIX
functionality is made available. The greater the value of this
macro, the more functionality is made available.
If you define this macro to a value greater than or equal to `1',
then the functionality from the 1990 edition of the POSIX.1
standard (IEEE Standard 1003.1-1990) is made available.
If you define this macro to a value greater than or equal to `2',
then the functionality from the 1992 edition of the POSIX.2
standard (IEEE Standard 1003.2-1992) is made available.
If you define this macro to a value greater than or equal to
`199309L', then the functionality from the 1993 edition of the
POSIX.1b standard (IEEE Standard 1003.1b-1993) is made available.
Greater values for `_POSIX_C_SOURCE' will enable future extensions.
The POSIX standards process will define these values as necessary,
and the GNU C Library should support them some time after they
become standardized. The 1996 edition of POSIX.1 (ISO/IEC 9945-1:
1996) states that if you define `_POSIX_C_SOURCE' to a value
greater than or equal to `199506L', then the functionality from
the 1996 edition is made available.
-- Macro: _BSD_SOURCE
If you define this macro, functionality derived from 4.3 BSD Unix
is included as well as the ISO C, POSIX.1, and POSIX.2 material.
Some of the features derived from 4.3 BSD Unix conflict with the
corresponding features specified by the POSIX.1 standard. If this
macro is defined, the 4.3 BSD definitions take precedence over the
POSIX definitions.
Due to the nature of some of the conflicts between 4.3 BSD and
POSIX.1, you need to use a special "BSD compatibility library"
when linking programs compiled for BSD compatibility. This is
because some functions must be defined in two different ways, one
of them in the normal C library, and one of them in the
compatibility library. If your program defines `_BSD_SOURCE', you
must give the option `-lbsd-compat' to the compiler or linker when
linking the program, to tell it to find functions in this special
compatibility library before looking for them in the normal C
-- Macro: _SVID_SOURCE
If you define this macro, functionality derived from SVID is
included as well as the ISO C, POSIX.1, POSIX.2, and X/Open
If you define this macro, functionality described in the X/Open
Portability Guide is included. This is a superset of the POSIX.1
and POSIX.2 functionality and in fact `_POSIX_SOURCE' and
`_POSIX_C_SOURCE' are automatically defined.
As the unification of all Unices, functionality only available in
BSD and SVID is also included.
If the macro `_XOPEN_SOURCE_EXTENDED' is also defined, even more
functionality is available. The extra functions will make all
functions available which are necessary for the X/Open Unix brand.
If the macro `_XOPEN_SOURCE' has the value 500 this includes all
functionality described so far plus some new definitions from the
Single Unix Specification, version 2.
If this macro is defined some extra functions are available which
rectify a few shortcomings in all previous standards.
Specifically, the functions `fseeko' and `ftello' are available.
Without these functions the difference between the ISO C interface
(`fseek', `ftell') and the low-level POSIX interface (`lseek')
would lead to problems.
This macro was introduced as part of the Large File Support
extension (LFS).
If you define this macro an additional set of functions is made
available which enables 32 bit systems to use files of sizes beyond
the usual limit of 2GB. This interface is not available if the
system does not support files that large. On systems where the
natural file size limit is greater than 2GB (i.e., on 64 bit
systems) the new functions are identical to the replaced functions.
The new functionality is made available by a new set of types and
functions which replace the existing ones. The names of these new
objects contain `64' to indicate the intention, e.g., `off_t' vs.
`off64_t' and `fseeko' vs. `fseeko64'.
This macro was introduced as part of the Large File Support
extension (LFS). It is a transition interface for the period when
64 bit offsets are not generally used (see `_FILE_OFFSET_BITS').
This macro determines which file system interface shall be used,
one replacing the other. Whereas `_LARGEFILE64_SOURCE' makes the
64 bit interface available as an additional interface,
`_FILE_OFFSET_BITS' allows the 64 bit interface to replace the old
If `_FILE_OFFSET_BITS' is undefined, or if it is defined to the
value `32', nothing changes. The 32 bit interface is used and
types like `off_t' have a size of 32 bits on 32 bit systems.
If the macro is defined to the value `64', the large file interface
replaces the old interface. I.e., the functions are not made
available under different names (as they are with
`_LARGEFILE64_SOURCE'). Instead the old function names now
reference the new functions, e.g., a call to `fseeko' now indeed
calls `fseeko64'.
This macro should only be selected if the system provides
mechanisms for handling large files. On 64 bit systems this macro
has no effect since the `*64' functions are identical to the
normal functions.
This macro was introduced as part of the Large File Support
extension (LFS).
-- Macro: _ISOC99_SOURCE
Until the revised ISO C standard is widely adopted the new features
are not automatically enabled. The GNU C Library nevertheless has
a complete implementation of the new standard and to enable the
new features the macro `_ISOC99_SOURCE' should be defined.
-- Macro: _GNU_SOURCE
If you define this macro, everything is included: ISO C89,
ISO C99, POSIX.1, POSIX.2, BSD, SVID, X/Open, LFS, and GNU
extensions. In the cases where POSIX.1 conflicts with BSD, the
POSIX definitions take precedence.
If you want to get the full effect of `_GNU_SOURCE' but make the
BSD definitions take precedence over the POSIX definitions, use
this sequence of definitions:
#define _GNU_SOURCE
#define _BSD_SOURCE
#define _SVID_SOURCE
Note that if you do this, you must link your program with the BSD
compatibility library by passing the `-lbsd-compat' option to the
compiler or linker. *NB:* If you forget to do this, you may get
very strange errors at run time.
-- Macro: _REENTRANT
-- Macro: _THREAD_SAFE
If you define one of these macros, reentrant versions of several
functions get declared. Some of the functions are specified in
POSIX.1c but many others are only available on a few other systems
or are unique to the GNU C Library. The problem is the delay in
the standardization of the thread safe C library interface.
Unlike on some other systems, no special version of the C library
must be used for linking. There is only one version but while
compiling this it must have been specified to compile as thread
We recommend you use `_GNU_SOURCE' in new programs. If you don't
specify the `-ansi' option to GCC and don't define any of these macros
explicitly, the effect is the same as defining `_POSIX_C_SOURCE' to 2
and `_POSIX_SOURCE', `_SVID_SOURCE', and `_BSD_SOURCE' to 1.
When you define a feature test macro to request a larger class of
features, it is harmless to define in addition a feature test macro for
a subset of those features. For example, if you define
`_POSIX_C_SOURCE', then defining `_POSIX_SOURCE' as well has no effect.
Likewise, if you define `_GNU_SOURCE', then defining either
`_POSIX_SOURCE' or `_POSIX_C_SOURCE' or `_SVID_SOURCE' as well has no
Note, however, that the features of `_BSD_SOURCE' are not a subset of
any of the other feature test macros supported. This is because it
defines BSD features that take precedence over the POSIX features that
are requested by the other macros. For this reason, defining
`_BSD_SOURCE' in addition to the other feature test macros does have an
effect: it causes the BSD features to take priority over the conflicting
POSIX features.

File:, Node: Roadmap to the Manual, Prev: Using the Library, Up: Introduction
1.4 Roadmap to the Manual
Here is an overview of the contents of the remaining chapters of this
* *note Error Reporting::, describes how errors detected by the
library are reported.
* *note Language Features::, contains information about library
support for standard parts of the C language, including things
like the `sizeof' operator and the symbolic constant `NULL', how
to write functions accepting variable numbers of arguments, and
constants describing the ranges and other properties of the
numerical types. There is also a simple debugging mechanism which
allows you to put assertions in your code, and have diagnostic
messages printed if the tests fail.
* *note Memory::, describes the GNU C Library's facilities for
managing and using virtual and real memory, including dynamic
allocation of virtual memory. If you do not know in advance how
much memory your program needs, you can allocate it dynamically
instead, and manipulate it via pointers.
* *note Character Handling::, contains information about character
classification functions (such as `isspace') and functions for
performing case conversion.
* *note String and Array Utilities::, has descriptions of functions
for manipulating strings (null-terminated character arrays) and
general byte arrays, including operations such as copying and
* *note I/O Overview::, gives an overall look at the input and output
facilities in the library, and contains information about basic
concepts such as file names.
* *note I/O on Streams::, describes I/O operations involving streams
(or `FILE *' objects). These are the normal C library functions
from `stdio.h'.
* *note Low-Level I/O::, contains information about I/O operations
on file descriptors. File descriptors are a lower-level mechanism
specific to the Unix family of operating systems.
* *note File System Interface::, has descriptions of operations on
entire files, such as functions for deleting and renaming them and
for creating new directories. This chapter also contains
information about how you can access the attributes of a file,
such as its owner and file protection modes.
* *note Pipes and FIFOs::, contains information about simple
interprocess communication mechanisms. Pipes allow communication
between two related processes (such as between a parent and
child), while FIFOs allow communication between processes sharing
a common file system on the same machine.
* *note Sockets::, describes a more complicated interprocess
communication mechanism that allows processes running on different
machines to communicate over a network. This chapter also
contains information about Internet host addressing and how to use
the system network databases.
* *note Low-Level Terminal Interface::, describes how you can change
the attributes of a terminal device. If you want to disable echo
of characters typed by the user, for example, read this chapter.
* *note Mathematics::, contains information about the math library
functions. These include things like random-number generators and
remainder functions on integers as well as the usual trigonometric
and exponential functions on floating-point numbers.
* *note Low-Level Arithmetic Functions: Arithmetic, describes
functions for simple arithmetic, analysis of floating-point
values, and reading numbers from strings.
* *note Searching and Sorting::, contains information about functions
for searching and sorting arrays. You can use these functions on
any kind of array by providing an appropriate comparison function.
* *note Pattern Matching::, presents functions for matching regular
expressions and shell file name patterns, and for expanding words
as the shell does.
* *note Date and Time::, describes functions for measuring both
calendar time and CPU time, as well as functions for setting
alarms and timers.
* *note Character Set Handling::, contains information about
manipulating characters and strings using character sets larger
than will fit in the usual `char' data type.
* *note Locales::, describes how selecting a particular country or
language affects the behavior of the library. For example, the
locale affects collation sequences for strings and how monetary
values are formatted.
* *note Non-Local Exits::, contains descriptions of the `setjmp' and
`longjmp' functions. These functions provide a facility for
`goto'-like jumps which can jump from one function to another.
* *note Signal Handling::, tells you all about signals--what they
are, how to establish a handler that is called when a particular
kind of signal is delivered, and how to prevent signals from
arriving during critical sections of your program.
* *note Program Basics::, tells how your programs can access their
command-line arguments and environment variables.
* *note Processes::, contains information about how to start new
processes and run programs.
* *note Job Control::, describes functions for manipulating process
groups and the controlling terminal. This material is probably
only of interest if you are writing a shell or other program which
handles job control specially.
* *note Name Service Switch::, describes the services which are
available for looking up names in the system databases, how to
determine which service is used for which database, and how these
services are implemented so that contributors can design their own
* *note User Database::, and *note Group Database::, tell you how to
access the system user and group databases.
* *note System Management::, describes functions for controlling and
getting information about the hardware and software configuration
your program is executing under.
* *note System Configuration::, tells you how you can get
information about various operating system limits. Most of these
parameters are provided for compatibility with POSIX.
* *note Library Summary::, gives a summary of all the functions,
variables, and macros in the library, with complete data types and
function prototypes, and says what standard or system each is
derived from.
* *note Installation::, explains how to build and install the GNU C
Library on your system, and how to report any bugs you might find.
* *note Maintenance::, explains how to add new functions or port the
library to a new system.
If you already know the name of the facility you are interested in,
you can look it up in *note Library Summary::. This gives you a
summary of its syntax and a pointer to where you can find a more
detailed description. This appendix is particularly useful if you just
want to verify the order and type of arguments to a function, for
example. It also tells you what standard or system each function,
variable, or macro is derived from.

File:, Node: Error Reporting, Next: Memory, Prev: Introduction, Up: Top
2 Error Reporting
Many functions in the GNU C Library detect and report error conditions,
and sometimes your programs need to check for these error conditions.
For example, when you open an input file, you should verify that the
file was actually opened correctly, and print an error message or take
other appropriate action if the call to the library function failed.
This chapter describes how the error reporting facility works. Your
program should include the header file `errno.h' to use this facility.
* Menu:
* Checking for Errors:: How errors are reported by library functions.
* Error Codes:: Error code macros; all of these expand
into integer constant values.
* Error Messages:: Mapping error codes onto error messages.

File:, Node: Checking for Errors, Next: Error Codes, Up: Error Reporting
2.1 Checking for Errors
Most library functions return a special value to indicate that they have
failed. The special value is typically `-1', a null pointer, or a
constant such as `EOF' that is defined for that purpose. But this
return value tells you only that an error has occurred. To find out
what kind of error it was, you need to look at the error code stored in
the variable `errno'. This variable is declared in the header file
-- Variable: volatile int errno
The variable `errno' contains the system error number. You can
change the value of `errno'.
Since `errno' is declared `volatile', it might be changed
asynchronously by a signal handler; see *note Defining Handlers::.
However, a properly written signal handler saves and restores the
value of `errno', so you generally do not need to worry about this
possibility except when writing signal handlers.
The initial value of `errno' at program startup is zero. Many
library functions are guaranteed to set it to certain nonzero
values when they encounter certain kinds of errors. These error
conditions are listed for each function. These functions do not
change `errno' when they succeed; thus, the value of `errno' after
a successful call is not necessarily zero, and you should not use
`errno' to determine _whether_ a call failed. The proper way to
do that is documented for each function. _If_ the call failed,
you can examine `errno'.
Many library functions can set `errno' to a nonzero value as a
result of calling other library functions which might fail. You
should assume that any library function might alter `errno' when
the function returns an error.
*Portability Note:* ISO C specifies `errno' as a "modifiable
lvalue" rather than as a variable, permitting it to be implemented
as a macro. For example, its expansion might involve a function
call, like `*__errno_location ()'. In fact, that is what it is on
GNU/Linux and GNU/Hurd systems. The GNU C Library, on each
system, does whatever is right for the particular system.
There are a few library functions, like `sqrt' and `atan', that
return a perfectly legitimate value in case of an error, but also
set `errno'. For these functions, if you want to check to see
whether an error occurred, the recommended method is to set `errno'
to zero before calling the function, and then check its value
All the error codes have symbolic names; they are macros defined in
`errno.h'. The names start with `E' and an upper-case letter or digit;
you should consider names of this form to be reserved names. *Note
Reserved Names::.
The error code values are all positive integers and are all distinct,
with one exception: `EWOULDBLOCK' and `EAGAIN' are the same. Since the
values are distinct, you can use them as labels in a `switch'
statement; just don't use both `EWOULDBLOCK' and `EAGAIN'. Your
program should not make any other assumptions about the specific values
of these symbolic constants.
The value of `errno' doesn't necessarily have to correspond to any
of these macros, since some library functions might return other error
codes of their own for other situations. The only values that are
guaranteed to be meaningful for a particular library function are the
ones that this manual lists for that function.
Except on GNU/Hurd systems, almost any system call can return
`EFAULT' if it is given an invalid pointer as an argument. Since this
could only happen as a result of a bug in your program, and since it
will not happen on GNU/Hurd systems, we have saved space by not
mentioning `EFAULT' in the descriptions of individual functions.
In some Unix systems, many system calls can also return `EFAULT' if
given as an argument a pointer into the stack, and the kernel for some
obscure reason fails in its attempt to extend the stack. If this ever
happens, you should probably try using statically or dynamically
allocated memory instead of stack memory on that system.

File:, Node: Error Codes, Next: Error Messages, Prev: Checking for Errors, Up: Error Reporting
2.2 Error Codes
The error code macros are defined in the header file `errno.h'. All of
them expand into integer constant values. Some of these error codes
can't occur on GNU systems, but they can occur using the GNU C Library
on other systems.
-- Macro: int EPERM
Operation not permitted; only the owner of the file (or other
resource) or processes with special privileges can perform the
-- Macro: int ENOENT
No such file or directory. This is a "file doesn't exist" error
for ordinary files that are referenced in contexts where they are
expected to already exist.
-- Macro: int ESRCH
No process matches the specified process ID.
-- Macro: int EINTR
Interrupted function call; an asynchronous signal occurred and
prevented completion of the call. When this happens, you should
try the call again.
You can choose to have functions resume after a signal that is
handled, rather than failing with `EINTR'; see *note Interrupted
-- Macro: int EIO
Input/output error; usually used for physical read or write errors.
-- Macro: int ENXIO
No such device or address. The system tried to use the device
represented by a file you specified, and it couldn't find the
device. This can mean that the device file was installed
incorrectly, or that the physical device is missing or not
correctly attached to the computer.
-- Macro: int E2BIG
Argument list too long; used when the arguments passed to a new
program being executed with one of the `exec' functions (*note
Executing a File::) occupy too much memory space. This condition
never arises on GNU/Hurd systems.
-- Macro: int ENOEXEC
Invalid executable file format. This condition is detected by the
`exec' functions; see *note Executing a File::.
-- Macro: int EBADF
Bad file descriptor; for example, I/O on a descriptor that has been
closed or reading from a descriptor open only for writing (or vice
-- Macro: int ECHILD
There are no child processes. This error happens on operations
that are supposed to manipulate child processes, when there aren't
any processes to manipulate.
-- Macro: int EDEADLK
Deadlock avoided; allocating a system resource would have resulted
in a deadlock situation. The system does not guarantee that it
will notice all such situations. This error means you got lucky
and the system noticed; it might just hang. *Note File Locks::,
for an example.
-- Macro: int ENOMEM
No memory available. The system cannot allocate more virtual
memory because its capacity is full.
-- Macro: int EACCES
Permission denied; the file permissions do not allow the attempted
-- Macro: int EFAULT
Bad address; an invalid pointer was detected. On GNU/Hurd
systems, this error never happens; you get a signal instead.
-- Macro: int ENOTBLK
A file that isn't a block special file was given in a situation
that requires one. For example, trying to mount an ordinary file
as a file system in Unix gives this error.
-- Macro: int EBUSY
Resource busy; a system resource that can't be shared is already
in use. For example, if you try to delete a file that is the root
of a currently mounted filesystem, you get this error.
-- Macro: int EEXIST
File exists; an existing file was specified in a context where it
only makes sense to specify a new file.
-- Macro: int EXDEV
An attempt to make an improper link across file systems was
detected. This happens not only when you use `link' (*note Hard
Links::) but also when you rename a file with `rename' (*note
Renaming Files::).
-- Macro: int ENODEV
The wrong type of device was given to a function that expects a
particular sort of device.
-- Macro: int ENOTDIR
A file that isn't a directory was specified when a directory is
-- Macro: int EISDIR
File is a directory; you cannot open a directory for writing, or
create or remove hard links to it.
-- Macro: int EINVAL
Invalid argument. This is used to indicate various kinds of
problems with passing the wrong argument to a library function.
-- Macro: int EMFILE
The current process has too many files open and can't open any
more. Duplicate descriptors do count toward this limit.
In BSD and GNU, the number of open files is controlled by a
resource limit that can usually be increased. If you get this
error, you might want to increase the `RLIMIT_NOFILE' limit or
make it unlimited; *note Limits on Resources::.
-- Macro: int ENFILE
There are too many distinct file openings in the entire system.
Note that any number of linked channels count as just one file
opening; see *note Linked Channels::. This error never occurs on
GNU/Hurd systems.
-- Macro: int ENOTTY
Inappropriate I/O control operation, such as trying to set terminal
modes on an ordinary file.
-- Macro: int ETXTBSY
An attempt to execute a file that is currently open for writing, or
write to a file that is currently being executed. Often using a
debugger to run a program is considered having it open for writing
and will cause this error. (The name stands for "text file
busy".) This is not an error on GNU/Hurd systems; the text is
copied as necessary.
-- Macro: int EFBIG
File too big; the size of a file would be larger than allowed by
the system.
-- Macro: int ENOSPC
No space left on device; write operation on a file failed because
the disk is full.
-- Macro: int ESPIPE
Invalid seek operation (such as on a pipe).
-- Macro: int EROFS
An attempt was made to modify something on a read-only file system.
-- Macro: int EMLINK
Too many links; the link count of a single file would bec