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This is, produced by makeinfo version 5.2 from libc.texinfo.
This file documents the GNU C Library.
This is 'The GNU C Library Reference Manual', for version 2.19
Copyright (C) 1993-2014 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
(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."
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.
* aligned_alloc: (libc)Aligned Memory Blocks.
* 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.
* 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_getspecific: (libc)Thread-specific Data.
* pthread_key_create: (libc)Thread-specific Data.
* pthread_key_delete: (libc)Thread-specific Data.
* pthread_setattr_default_np: (libc)Default Thread Attributes.
* pthread_setspecific: (libc)Thread-specific Data.
* 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.
* shm_open: (libc)Memory-mapped I/O.
* shm_unlink: (libc)Memory-mapped I/O.
* 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.

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

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

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

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

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

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

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

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

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

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

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

File:, Node: Calling Wordexp, Next: Flags for Wordexp, Prev: Expansion Stages, Up: Word Expansion
10.4.2 Calling 'wordexp'
All the functions, constants and data types for word expansion are
declared in the header file 'wordexp.h'.
Word expansion produces a vector of words (strings). To return this
vector, 'wordexp' uses a special data type, 'wordexp_t', which is a
structure. You pass 'wordexp' the address of the structure, and it
fills in the structure's fields to tell you about the results.
-- Data Type: wordexp_t
This data type holds a pointer to a word vector. More precisely,
it records both the address of the word vector and its size.
The number of elements in the vector.
The address of the vector. This field has type 'char **'.
The offset of the first real element of the vector, from its
nominal address in the 'we_wordv' field. Unlike the other
fields, this is always an input to 'wordexp', rather than an
output from it.
If you use a nonzero offset, then that many elements at the
beginning of the vector are left empty. (The 'wordexp'
function fills them with null pointers.)
The 'we_offs' field is meaningful only if you use the
'WRDE_DOOFFS' flag. Otherwise, the offset is always zero
regardless of what is in this field, and the first real
element comes at the beginning of the vector.
-- Function: int wordexp (const char *WORDS, wordexp_t
Preliminary: | MT-Unsafe race:utent const:env env sig:ALRM timer
locale | AS-Unsafe dlopen plugin i18n heap corrupt lock | AC-Unsafe
corrupt lock fd mem | *Note POSIX Safety Concepts::.
Perform word expansion on the string WORDS, putting the result in a
newly allocated vector, and store the size and address of this
vector into '*WORD-VECTOR-PTR'. The argument FLAGS is a
combination of bit flags; see *note Flags for Wordexp::, for
details of the flags.
You shouldn't use any of the characters '|&;<>' in the string WORDS
unless they are quoted; likewise for newline. If you use these
characters unquoted, you will get the 'WRDE_BADCHAR' error code.
Don't use parentheses or braces unless they are quoted or part of a
word expansion construct. If you use quotation characters ''"`',
they should come in pairs that balance.
The results of word expansion are a sequence of words. The
function 'wordexp' allocates a string for each resulting word, then
allocates a vector of type 'char **' to store the addresses of
these strings. The last element of the vector is a null pointer.
This vector is called the "word vector".
To return this vector, 'wordexp' stores both its address and its
length (number of elements, not counting the terminating null
pointer) into '*WORD-VECTOR-PTR'.
If 'wordexp' succeeds, it returns 0. Otherwise, it returns one of
these error codes:
The input string WORDS contains an unquoted invalid character
such as '|'.
The input string refers to an undefined shell variable, and
you used the flag 'WRDE_UNDEF' to forbid such references.
The input string uses command substitution, and you used the
flag 'WRDE_NOCMD' to forbid command substitution.
It was impossible to allocate memory to hold the result. In
this case, 'wordexp' can store part of the results--as much as
it could allocate room for.
There was a syntax error in the input string. For example, an
unmatched quoting character is a syntax error.
-- Function: void wordfree (wordexp_t *WORD-VECTOR-PTR)
Preliminary: | MT-Safe | AS-Unsafe corrupt heap | AC-Unsafe corrupt
mem | *Note POSIX Safety Concepts::.
Free the storage used for the word-strings and vector that
'*WORD-VECTOR-PTR' points to. This does not free the structure
'*WORD-VECTOR-PTR' itself--only the other data it points to.

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

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

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

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

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

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

File:, Node: Streams and File Descriptors, Next: File Position, Up: I/O Concepts
11.1.1 Streams and File Descriptors
When you want to do input or output to a file, you have a choice of two
basic mechanisms for representing the connection between your program
and the file: file descriptors and streams. File descriptors are
represented as objects of type 'int', while streams are represented as
'FILE *' objects.
File descriptors provide a primitive, low-level interface to input
and output operations. Both file descriptors and streams can represent
a connection to a device (such as a terminal), or a pipe or socket for
communicating with another process, as well as a normal file. But, if
you want to do control operations that are specific to a particular kind
of device, you must use a file descriptor; there are no facilities to
use streams in this way. You must also use file descriptors if your
program needs to do input or output in special modes, such as
nonblocking (or polled) input (*note File Status Flags::).
Streams provide a higher-level interface, layered on top of the
primitive file descriptor facilities. The stream interface treats all
kinds of files pretty much alike--the sole exception being the three
styles of buffering that you can choose (*note Stream Buffering::).
The main advantage of using the stream interface is that the set of
functions for performing actual input and output operations (as opposed
to control operations) on streams is much richer and more powerful than
the corresponding facilities for file descriptors. The file descriptor
interface provides only simple functions for transferring blocks of
characters, but the stream interface also provides powerful formatted
input and output functions ('printf' and 'scanf') as well as functions
for character- and line-oriented input and output.
Since streams are implemented in terms of file descriptors, you can
extract the file descriptor from a stream and perform low-level
operations directly on the file descriptor. You can also initially open
a connection as a file descriptor and then make a stream associated with
that file descriptor.
In general, you should stick with using streams rather than file
descriptors, unless there is some specific operation you want to do that
can only be done on a file descriptor. If you are a beginning
programmer and aren't sure what functions to use, we suggest that you
concentrate on the formatted input functions (*note Formatted Input::)
and formatted output functions (*note Formatted Output::).
If you are concerned about portability of your programs to systems
other than GNU, you should also be aware that file descriptors are not
as portable as streams. You can expect any system running ISO C to
support streams, but non-GNU systems may not support file descriptors at
all, or may only implement a subset of the GNU functions that operate on
file descriptors. Most of the file descriptor functions in the GNU C
Library are included in the POSIX.1 standard, however.

File:, Node: File Position, Prev: Streams and File Descriptors, Up: I/O Concepts
11.1.2 File Position
One of the attributes of an open file is its "file position" that keeps
track of where in the file the next character is to be read or written.
On GNU systems, and all POSIX.1 systems, the file position is simply an
integer representing the number of bytes from the beginning of the file.
The file position is normally set to the beginning of the file when
it is opened, and each time a character is read or written, the file
position is incremented. In other words, access to the file is normally
Ordinary files permit read or write operations at any position within
the file. Some other kinds of files may also permit this. Files which
do permit this are sometimes referred to as "random-access" files. You
can change the file position using the 'fseek' function on a stream
(*note File Positioning::) or the 'lseek' function on a file descriptor
(*note I/O Primitives::). If you try to change the file position on a
file that doesn't support random access, you get the 'ESPIPE' error.
Streams and descriptors that are opened for "append access" are
treated specially for output: output to such files is _always_ appended
sequentially to the _end_ of the file, regardless of the file position.
However, the file position is still used to control where in the file
reading is done.
If you think about it, you'll realize that several programs can read
a given file at the same time. In order for each program to be able to
read the file at its own pace, each program must have its own file
pointer, which is not affected by anything the other programs do.
In fact, each opening of a file creates a separate file position.
Thus, if you open a file twice even in the same program, you get two
streams or descriptors with independent file positions.
By contrast, if you open a descriptor and then duplicate it to get
another descriptor, these two descriptors share the same file position:
changing the file position of one descriptor will affect the other.

File:, Node: File Names, Prev: I/O Concepts, Up: I/O Overview
11.2 File Names
In order to open a connection to a file, or to perform other operations
such as deleting a file, you need some way to refer to the file. Nearly
all files have names that are strings--even files which are actually
devices such as tape drives or terminals. These strings are called
"file names". You specify the file name to say which file you want to
open or operate on.
This section describes the conventions for file names and how the
operating system works with them.
* Menu:
* 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.

File:, Node: Directories, Next: File Name Resolution, Up: File Names
11.2.1 Directories
In order to understand the syntax of file names, you need to understand
how the file system is organized into a hierarchy of directories.
A "directory" is a file that contains information to associate other
files with names; these associations are called "links" or "directory
entries". Sometimes, people speak of "files in a directory", but in
reality, a directory only contains pointers to files, not the files
The name of a file contained in a directory entry is called a "file
name component". In general, a file name consists of a sequence of one
or more such components, separated by the slash character ('/'). A file
name which is just one component names a file with respect to its
directory. A file name with multiple components names a directory, and
then a file in that directory, and so on.
Some other documents, such as the POSIX standard, use the term
"pathname" for what we call a file name, and either "filename" or
"pathname component" for what this manual calls a file name component.
We don't use this terminology because a "path" is something completely
different (a list of directories to search), and we think that
"pathname" used for something else will confuse users. We always use
"file name" and "file name component" (or sometimes just "component",
where the context is obvious) in GNU documentation. Some macros use the
POSIX terminology in their names, such as 'PATH_MAX'. These macros are
defined by the POSIX standard, so we cannot change their names.
You can find more detailed information about operations on
directories in *note File System Interface::.

File:, Node: File Name Resolution, Next: File Name Errors, Prev: Directories, Up: File Names
11.2.2 File Name Resolution
A file name consists of file name components separated by slash ('/')
characters. On the systems that the GNU C Library supports, multiple
successive '/' characters are equivalent to a single '/' character.
The process of determining what file a file name refers to is called
"file name resolution". This is performed by examining the components
that make up a file name in left-to-right order, and locating each
successive component in the directory named by the previous component.
Of course, each of the files that are referenced as directories must
actually exist, be directories instead of regular files, and have the
appropriate permissions to be accessible by the process; otherwise the
file name resolution fails.
If a file name begins with a '/', the first component in the file
name is located in the "root directory" of the process (usually all
processes on the system have the same root directory). Such a file name
is called an "absolute file name".
Otherwise, the first component in the file name is located in the
current working directory (*note Working Directory::). This kind of
file name is called a "relative file name".
The file name components '.' ("dot") and '..' ("dot-dot") have
special meanings. Every directory has entries for these file name
components. The file name component '.' refers to the directory itself,
while the file name component '..' refers to its "parent directory" (the
directory that contains the link for the directory in question). As a
special case, '..' in the root directory refers to the root directory
itself, since it has no parent; thus '/..' is the same as '/'.
Here are some examples of file names:
The file named 'a', in the root directory.
The file named 'b', in the directory named 'a' in the root
The file named 'a', in the current working directory.
This is the same as '/a/b'.
The file named 'a', in the current working directory.
The file named 'a', in the parent directory of the current working
A file name that names a directory may optionally end in a '/'. You
can specify a file name of '/' to refer to the root directory, but the
empty string is not a meaningful file name. If you want to refer to the
current working directory, use a file name of '.' or './'.
Unlike some other operating systems, GNU systems don't have any
built-in support for file types (or extensions) or file versions as part
of its file name syntax. Many programs and utilities use conventions
for file names--for example, files containing C source code usually have
names suffixed with '.c'--but there is nothing in the file system itself
that enforces this kind of convention.

File:, Node: File Name Errors, Next: File Name Portability, Prev: File Name Resolution, Up: File Names
11.2.3 File Name Errors
Functions that accept file name arguments usually detect these 'errno'
error conditions relating to the file name syntax or trouble finding the
named file. These errors are referred to throughout this manual as the
"usual file name errors".
The process does not have search permission for a directory
component of the file name.
This error is used when either the total length of a file name is
greater than 'PATH_MAX', or when an individual file name component
has a length greater than 'NAME_MAX'. *Note Limits for Files::.
On GNU/Hurd systems, there is no imposed limit on overall file name
length, but some file systems may place limits on the length of a
This error is reported when a file referenced as a directory
component in the file name doesn't exist, or when a component is a
symbolic link whose target file does not exist. *Note Symbolic
A file that is referenced as a directory component in the file name
exists, but it isn't a directory.
Too many symbolic links were resolved while trying to look up the
file name. The system has an arbitrary limit on the number of
symbolic links that may be resolved in looking up a single file
name, as a primitive way to detect loops. *Note Symbolic Links::.

File:, Node: File Name Portability, Prev: File Name Errors, Up: File Names
11.2.4 Portability of File Names
The rules for the syntax of file names discussed in *note File Names::,
are the rules normally used by GNU systems and by other POSIX systems.
However, other operating systems may use other conventions.
There are two reasons why it can be important for you to be aware of
file name portability issues:
* If your program makes assumptions about file name syntax, or
contains embedded literal file name strings, it is more difficult
to get it to run under other operating systems that use different
syntax conventions.
* Even if you are not concerned about running your program on
machines that run other operating systems, it may still be possible
to access files that use different naming conventions. For
example, you may be able to access file systems on another computer
running a different operating system over a network, or read and
write disks in formats used by other operating systems.
The ISO C standard says very little about file name syntax, only that
file names are strings. In addition to varying restrictions on the
length of file names and what characters can validly appear in a file
name, different operating systems use different conventions and syntax
for concepts such as structured directories and file types or
extensions. Some concepts such as file versions might be supported in
some operating systems and not by others.
The POSIX.1 standard allows implementations to put additional
restrictions on file name syntax, concerning what characters are
permitted in file names and on the length of file name and file name
component strings. However, on GNU systems, any character except the
null character is permitted in a file name string, and on GNU/Hurd
systems there are no limits on the length of file name strings.

File:, Node: I/O on Streams, Next: Low-Level I/O, Prev: I/O Overview, Up: Top
12 Input/Output on Streams
This chapter describes the functions for creating streams and performing
input and output operations on them. As discussed in *note I/O
Overview::, a stream is a fairly abstract, high-level concept
representing a communications channel to a file, device, or process.
* Menu:
* 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.

File:, Node: Streams, Next: Standard Streams, Up: I/O on Streams
12.1 Streams
For historical reasons, the type of the C data structure that represents
a stream is called 'FILE' rather than "stream". Since most of the
library functions deal with objects of type 'FILE *', sometimes the term
"file pointer" is also used to mean "stream". This leads to unfortunate
confusion over terminology in many books on C. This manual, however, is
careful to use the terms "file" and "stream" only in the technical
The 'FILE' type is declared in the header file 'stdio.h'.
-- Data Type: FILE
This is the data type used to represent stream objects. A 'FILE'
object holds all of the internal state information about the
connection to the associated file, including such things as the
file position indicator and buffering information. Each stream
also has error and end-of-file status indicators that can be tested
with the 'ferror' and 'feof' functions; see *note EOF and Errors::.
'FILE' objects are allocated and managed internally by the
input/output library functions. Don't try to create your own objects of
type 'FILE'; let the library do it. Your programs should deal only with
pointers to these objects (that is, 'FILE *' values) rather than the
objects themselves.

File:, Node: Standard Streams, Next: Opening Streams, Prev: Streams, Up: I/O on Streams
12.2 Standard Streams
When the 'main' function of your program is invoked, it already has
three predefined streams open and available for use. These represent
the "standard" input and output channels that have been established for
the process.
These streams are declared in the header file 'stdio.h'.
-- Variable: FILE * stdin
The "standard input" stream, which is the normal source of input
for the program.
-- Variable: FILE * stdout
The "standard output" stream, which is used for normal output from
the program.
-- Variable: FILE * stderr
The "standard error" stream, which is used for error messages and
diagnostics issued by the program.
On GNU systems, you can specify what files or processes correspond to
these streams using the pipe and redirection facilities provided by the
shell. (The primitives shells use to implement these facilities are
described in *note File System Interface::.) Most other operating
systems provide similar mechanisms, but the details of how to use them
can vary.
In the GNU C Library, 'stdin', 'stdout', and 'stderr' are normal
variables which you can set just like any others. For example, to
redirect the standard output to a file, you could do:
fclose (stdout);
stdout = fopen ("standard-output-file", "w");
Note however, that in other systems 'stdin', 'stdout', and 'stderr'
are macros that you cannot assign to in the normal way. But you can use
'freopen' to get the effect of closing one and reopening it. *Note
Opening Streams::.
The three streams 'stdin', 'stdout', and 'stderr' are not unoriented
at program start (*note Streams and I18N::).

File:, Node: Opening Streams, Next: Closing Streams, Prev: Standard Streams, Up: I/O on Streams
12.3 Opening Streams
Opening a file with the 'fopen' function creates a new stream and
establishes a connection between the stream and a file. This may
involve creating a new file.
Everything described in this section is declared in the header file
-- Function: FILE * fopen (const char *FILENAME, const char *OPENTYPE)
Preliminary: | MT-Safe | AS-Unsafe heap lock | AC-Unsafe mem fd
lock | *Note POSIX Safety Concepts::.
The 'fopen' function opens a stream for I/O to the file FILENAME,
and returns a pointer to the stream.
The OPENTYPE argument is a string that controls how the file is
opened and specifies attributes of the resulting stream. It must
begin with one of the following sequences of characters:
Open an existing file for reading only.
Open the file for writing only. If the file already exists,
it is truncated to zero length. Otherwise a new file is
Open a file for append access; that is, writing at the end of
file only. If the file already exists, its initial contents
are unchanged and output to the stream is appended to the end
of the file. Otherwise, a new, empty file is created.
Open an existing file for both reading and writing. The
initial contents of the file are unchanged and the initial
file position is at the beginning of the file.
Open a file for both reading and writing. If the file already
exists, it is truncated to zero length. Otherwise, a new file
is created.
Open or create file for both reading and appending. If the
file exists, its initial contents are unchanged. Otherwise, a
new file is created. The initial file position for reading is
at the beginning of the file, but output is always appended to
the end of the file.
As you can see, '+' requests a stream that can do both input and
output. When using such a stream, you must call 'fflush' (*note
Stream Buffering::) or a file positioning function such as 'fseek'
(*note File Positioning::) when switching from reading to writing
or vice versa. Otherwise, internal buffers might not be emptied
Additional characters may appear after these to specify flags for
the call. Always put the mode ('r', 'w+', etc.) first; that is
the only part you are guaranteed will be understood by all systems.
The GNU C Library defines additional characters for use in
The file is opened with cancellation in the I/O functions
The underlying file descriptor will be closed if you use any
of the 'exec...' functions (*note Executing a File::). (This
is equivalent to having set 'FD_CLOEXEC' on that descriptor.
*Note Descriptor Flags::.)
The file is opened and accessed using 'mmap'. This is only
supported with files opened for reading.
Insist on creating a new file--if a file FILENAME already
exists, 'fopen' fails rather than opening it. If you use 'x'
you are guaranteed that you will not clobber an existing file.
This is equivalent to the 'O_EXCL' option to the 'open'
function (*note Opening and Closing Files::).
The 'x' modifier is part of ISO C11.
The character 'b' in OPENTYPE has a standard meaning; it requests a
binary stream rather than a text stream. But this makes no
difference in POSIX systems (including GNU systems). If both '+'
and 'b' are specified, they can appear in either order. *Note
Binary Streams::.
If the OPENTYPE string contains the sequence ',ccs=STRING' then
STRING is taken as the name of a coded character set and 'fopen'
will mark the stream as wide-oriented with appropriate conversion
functions in place to convert from and to the character set STRING.
Any other stream is opened initially unoriented and the orientation
is decided with the first file operation. If the first operation
is a wide character operation, the stream is not only marked as
wide-oriented, also the conversion functions to convert to the
coded character set used for the current locale are loaded. This
will not change anymore from this point on even if the locale
selected for the 'LC_CTYPE' category is changed.
Any other characters in OPENTYPE are simply ignored. They may be
meaningful in other systems.
If the open fails, 'fopen' returns a null pointer.
When the sources are compiling with '_FILE_OFFSET_BITS == 64' on a
32 bit machine this function is in fact 'fopen64' since the LFS
interface replaces transparently the old interface.
You can have multiple streams (or file descriptors) pointing to the
same file open at the same time. If you do only input, this works
straightforwardly, but you must be careful if any output streams are
included. *Note Stream/Descriptor Precautions::. This is equally true
whether the streams are in one program (not usual) or in several
programs (which can easily happen). It may be advantageous to use the
file locking facilities to avoid simultaneous access. *Note File
-- Function: FILE * fopen64 (const char *FILENAME, const char
Preliminary: | MT-Safe | AS-Unsafe heap lock | AC-Unsafe mem fd
lock | *Note POSIX Safety Concepts::.
This function is similar to 'fopen' but the stream it returns a
pointer for is opened using 'open64'. Therefore this stream can be
used even on files larger than 2^31 bytes on 32 bit machines.
Please note that the return type is still 'FILE *'. There is no
special 'FILE' type for the LFS interface.
If the sources are compiled with '_FILE_OFFSET_BITS == 64' on a 32
bits machine this function is available under the name 'fopen' and
so transparently replaces the old interface.
-- Macro: int FOPEN_MAX
The value of this macro is an integer constant expression that
represents the minimum number of streams that the implementation
guarantees can be open simultaneously. You might be able to open
more than this many streams, but that is not guaranteed. The value
of this constant is at least eight, which includes the three
standard streams 'stdin', 'stdout', and 'stderr'. In POSIX.1
systems this value is determined by the 'OPEN_MAX' parameter; *note
General Limits::. In BSD and GNU, it is controlled by the
'RLIMIT_NOFILE' resource limit; *note Limits on Resources::.
-- Function: FILE * freopen (const char *FILENAME, const char
Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt fd |
*Note POSIX Safety Concepts::.
This function is like a combination of 'fclose' and 'fopen'. It
first closes the stream referred to by STREAM, ignoring any errors
that are detected in the process. (Because errors are ignored, you
should not use 'freopen' on an output stream if you have actually
done any output using the stream.) Then the file named by FILENAME
is opened with mode OPENTYPE as for 'fopen', and associated with
the same stream object STREAM.
If the operation fails, a null pointer is returned; otherwise,
'freopen' returns STREAM.
'freopen' has traditionally been used to connect a standard stream
such as 'stdin' with a file of your own choice. This is useful in
programs in which use of a standard stream for certain purposes is
hard-coded. In the GNU C Library, you can simply close the
standard streams and open new ones with 'fopen'. But other systems
lack this ability, so using 'freopen' is more portable.
When the sources are compiling with '_FILE_OFFSET_BITS == 64' on a
32 bit machine this function is in fact 'freopen64' since the LFS
interface replaces transparently the old interface.
-- Function: FILE * freopen64 (const char *FILENAME, const char
Preliminary: | MT-Safe | AS-Unsafe corrupt | AC-Unsafe corrupt fd |
*Note POSIX Safety Concepts::.
This function is similar to 'freopen'. The only difference is that
on 32 bit machine the stream returned is able to read beyond the
2^31 bytes limits imposed by the normal interface. It should be
noted that the stream pointed to by STREAM need not be opened using
'fopen64' or 'freopen64' since its mode is not important for this
If the sources are compiled with '_FILE_OFFSET_BITS == 64' on a 32
bits machine this function is available under the name 'freopen'
and so transparently replaces the old interface.
In some situations it is useful to know whether a given stream is
available for reading or writing. This information is normally not
available and would have to be remembered separately. Solaris
introduced a few functions to get this information from the stream
descriptor and these functions are also available in the GNU C Library.
-- Function: int __freadable (FILE *STREAM)
Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
The '__freadable' function determines whether the stream STREAM was
opened to allow reading. In this case the return value is nonzero.
For write-only streams the function returns zero.
This function is declared in 'stdio_ext.h'.
-- Function: int __fwritable (FILE *STREAM)
Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
The '__fwritable' function determines whether the stream STREAM was
opened to allow writing. In this case the return value is nonzero.
For read-only streams the function returns zero.
This function is declared in 'stdio_ext.h'.
For slightly different kind of problems there are two more functions.
They provide even finer-grained information.
-- Function: int __freading (FILE *STREAM)
Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
The '__freading' function determines whether the stream STREAM was
last read from or whether it is opened read-only. In this case the
return value is nonzero, otherwise it is zero. Determining whether
a stream opened for reading and writing was last used for writing
allows to draw conclusions about the content about the buffer,
among other things.
This function is declared in 'stdio_ext.h'.
-- Function: int __fwriting (FILE *STREAM)
Preliminary: | MT-Safe | AS-Safe | AC-Safe | *Note POSIX Safety
The '__fwriting' function determines whether the stream STREAM was
last written to or whether it is opened write-only. In this case
the return value is nonzero, otherwise it is zero.
This function is declared in 'stdio_ext.h'.

File:, Node: Closing Streams, Next: Streams and Threads, Prev: Opening Streams, Up: I/O on Streams
12.4 Closing Streams
When a stream is closed with 'fclose', the connection between the stream
and the file is canceled. After you have closed a stream, you cannot
perform any additional operations on it.
-- Function: int fclose (FILE *STREAM)
Preliminary: | MT-Safe | AS-Unsafe heap lock | AC-Unsafe lock mem
fd | *Note POSIX Safety Concepts::.
This function causes STREAM to be closed and the connection to the
corresponding file to be broken. Any buffered output is written
and any buffered input is discarded. The 'fclose' function returns
a value of '0' if the file was closed successfully, and 'EOF' if an
error was detected.
It is important to check for errors when you call 'fclose' to close
an output stream, because real, everyday errors can be detected at
this time. For example, when 'fclose' writes the remaining
buffered output, it might get an error because the disk is full.
Even if you know the buffer is empty, errors can still occur when
closing a file if you are using NFS.
The function 'fclose' is declared in 'stdio.h'.
To close all streams currently available the GNU C Library provides
another function.
-- Function: int fcloseall (void)
Preliminary: | MT-Unsafe race:streams | AS-Unsafe | AC-Safe | *Note
POSIX Safety Concepts::.
This function causes all open streams of the process to be closed
and the connection to corresponding files to be broken. All
buffered data is written and any buffered input is discarded. The
'fcloseall' function returns a value of '0' if all the files were
closed successfully, and 'EOF' if an error was detected.
This function should be used only in special situations, e.g., when
an error occurred and the program must be aborted. Normally each
single stream should be closed separately so that problems with
individual streams can be identified. It is also problematic since
the standard streams (*note Standard Streams::) will also be
The function 'fcloseall' is declared in 'stdio.h'.
If the 'main' function to your program returns, or if you call the
'exit' function (*note Normal Termination::), all open streams are
automatically closed properly. If your program terminates in any other
manner, such as by calling the 'abort' function (*note Aborting a
Program::) or from a fatal signal (*note Signal Handling::), open
streams might not be closed properly. Buffered output might not be
flushed and files may be incomplete. For more information on buffering
of streams, see *note Stream Buffering::.

File:, Node: Streams and Threads, Next: Streams and I18N, Prev: Closing Streams, Up: I/O on Streams
12.5 Streams and Threads
Streams can be used in multi-threaded applications in the same way they
are used in single-threaded applications. But the programmer must be
aware of the possible complications. It is important to know about
these also if the program one writes never use threads since the design
and implementation of many stream functions is heavily influenced by the
requirements added by multi-threaded programming.
The POSIX standard requires that by default the stream operations are
atomic. I.e., issuing two stream operations for the same stream in two
threads at the same time will cause the operations to be executed as if
they were issued sequentially. The buffer operations performed while
reading or writing are protected from other uses of the same stream. To
do this each stream has an internal lock object which has to be
(implicitly) acquired before any work can be done.
But there are situations where this is not enough and there are also
situations where this is not wanted. The implicit locking is not enough
if the program requires more than one stream function call to happen
atomically. One example would be if an output line a program wants to
generate is created by several function calls. The functions by
themselves would ensure only atomicity of their own operation, but not
atomicity over all the function calls. For this it is necessary to
perform the stream locking in the application code.
-- Function: void flockfile (FILE *STREAM)
Preliminary: | MT-Safe | AS-Safe | AC-Unsafe lock | *Note POSIX
Safety Concepts::.
The 'flockfile' function acquires the internal locking object
associated with the stream STREAM. This ensures that no other
thread can explicitly through 'flockfile'/'ftrylockfile' or
implicit through a call of a stream function lock the stream. The
thread will block until the lock is acquired. An explicit call to
'funlockfile' has to be used to release the lock.
-- Function: int ftrylockfile (FILE *STREAM)
Preliminary: | MT-Safe | AS-Safe | AC-Unsafe lock | *Note POSIX
Safety Concepts::.
The 'ftrylockfile' function tries to acquire the internal locking
object associated with the stream STREAM just like 'flockfile'.
But unlike 'flockfile' this function does not block if the lock is
not available. 'ftrylockfile' returns zero if the lock was
successfully acquired. Otherwise the stream is locked by another
-- Function: void funlockfile (FILE *STREAM)
Preliminary: | MT-Safe | AS-Safe | AC-Unsafe lock | *Note POSIX
Safety Concepts::.
The 'funlockfile' function releases the internal locking object of
the stream STREAM. The stream must have been locked before by a
call to 'flockfile' or a successful call of 'ftrylockfile'. The
implicit locking performed by the stream operations do not count.
The 'funlockfile' function does not return an error status and the
behavior of a call for a stream which is not locked by the current
thread is undefined.
The following example shows how the functions above can be used to
generate an output line atomically even in multi-threaded applications
(yes, the same job could be done with one 'fprintf' call but it is
sometimes not possible):
FILE *fp;
flockfile (fp);
fputs ("This is test number ", fp);
fprintf (fp, "%d\n", test);
funlockfile (fp)
Without the explicit locking it would be possible for another thread
to use the stream FP after the 'fputs' call return and before 'fprintf'
was called with the result that the number does not follow the word
From this description it might already be clear that the locking
objects in streams are no simple mutexes. Since locking the same stream