posix/unistd.h

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 /*
  20  *      POSIX Standard: 2.10 Symbolic Constants         <unistd.h>
  21  */
  22
  23 #ifndef _UNISTD_H
  24
  25 #define _UNISTD_H       1
  26 #include <features.h>
  27
  28 __BEGIN_DECLS
  29
  30 /* These may be used to determine what facilities are present at compile time.
  31    Their values can be obtained at run time from sysconf.  */
  32
  33 /* POSIX Standard approved as IEEE Std 1003.1 as of August, 1988.  */
  34 #define _POSIX_VERSION  199009L
  35
  36 /* These are not #ifdef __USE_POSIX2 because they are
  37    in the theoretically application-owned namespace.  */
  38
  39 #define _POSIX2_C_VERSION       199912L /* Invalid until 1003.2 is done.  */
  40
  41 /* If defined, the implementation supports the
  42    C Language Bindings Option.  */
  43 #define _POSIX2_C_BIND  1
  44
  45 /* If defined, the implementation supports the
  46    C Language Development Utilities Option.  */
  47 #define _POSIX2_C_DEV   1
  48
  49 /* If defined, the implementation supports the
  50    Software Development Utilities Option.  */
  51 #define _POSIX2_SW_DEV  1
  52
  53
  54 /* Get values of POSIX options:
  55
  56    If these symbols are defined, the corresponding features are
  57    always available.  If not, they may be available sometimes.
  58    The current values can be obtained with `sysconf'.
  59
  60    _POSIX_JOB_CONTROL   Job control is supported.
  61    _POSIX_SAVED_IDS     Processes have a saved set-user-ID
  62                         and a saved set-group-ID.
  63
  64    If any of these symbols is defined as -1, the corresponding option is not
  65    true for any file.  If any is defined as other than -1, the corresponding
  66    option is true for all files.  If a symbol is not defined at all, the value
  67    for a specific file can be obtained from `pathconf' and `fpathconf'.
  68
  69    _POSIX_CHOWN_RESTRICTED      Only the super user can use `chown' to change
  70                                 the owner of a file.  `chown' can only be used
  71                                 to change the group ID of a file to a group of
  72                                 which the calling process is a member.
  73    _POSIX_NO_TRUNC              Pathname components longer than
  74                                 NAME_MAX generate an error.
  75    _POSIX_VDISABLE              If defined, if the value of an element of the
  76                                 `c_cc' member of `struct termios' is
  77                                 _POSIX_VDISABLE, no character will have the
  78                                 effect associated with that element.
  79    */
  80
  81 #include <posix_opt.h>
  82
  83
  84 /* Standard file descriptors.  */
  85 #define STDIN_FILENO    0       /* Standard input.  */
  86 #define STDOUT_FILENO   1       /* Standard output.  */
  87 #define STDERR_FILENO   2       /* Standard error output.  */
  88
  89
  90 /* All functions that are not declared anywhere else.  */
  91
  92 #include <gnu/types.h>
  93
  94 #ifndef ssize_t
  95 #define ssize_t __ssize_t
  96 #endif
  97
  98 #define __need_size_t
  99 #define __need_NULL
 100 #include <stddef.h>
 101
 102
 103 /* Values for the second argument to access.
 104    These may be OR'd together.  */
 105 #define R_OK    4               /* Test for read permission.  */
 106 #define W_OK    2               /* Test for write permission.  */
 107 #define X_OK    1               /* Test for execute permission.  */
 108 #define F_OK    0               /* Test for existence.  */
 109
 110 /* Test for access to NAME.  */
 111 extern int __access __P ((__const char *__name, int __type));
 112 extern int access __P ((__const char *__name, int __type));
 113
 114
 115 /* Values for the WHENCE argument to lseek.  */
 116 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 117 #define SEEK_SET        0       /* Seek from beginning of file.  */
 118 #define SEEK_CUR        1       /* Seek from current position.  */
 119 #define SEEK_END        2       /* Seek from end of file.  */
 120 #endif
 121
 122 /* Move FD's file position to OFFSET bytes from the
 123    beginning of the file (if WHENCE is SEEK_SET),
 124    the current position (if WHENCE is SEEK_CUR),
 125    or the end of the file (if WHENCE is SEEK_END).
 126    Return the new file position.  */
 127 extern __off_t __lseek __P ((int __fd, __off_t __offset, int __whence));
 128 extern __off_t lseek __P ((int __fd, __off_t __offset, int __whence));
 129
 130 /* Close the file descriptor FD.  */
 131 extern int __close __P ((int __fd));
 132 extern int close __P ((int __fd));
 133
 134 /* Read NBYTES into BUF from FD.  Return the
 135    number read, -1 for errors or 0 for EOF.  */
 136 extern ssize_t __read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 137 extern ssize_t read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 138
 139 /* Write N bytes of BUF to FD.  Return the number written, or -1.  */
 140 extern ssize_t __write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 141 extern ssize_t write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 142
 143
 144 /* Create a one-way communication channel (pipe).
 145    If successul, two file descriptors are stored in PIPEDES;
 146    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 147    Returns 0 if successful, -1 if not.  */
 148 extern int __pipe __P ((int __pipedes[2]));
 149 extern int pipe __P ((int __pipedes[2]));
 150
 151 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 152    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 153    The function returns the number of seconds remaining until the last
 154    alarm scheduled would have signaled, or zero if there wasn't one.
 155    There is no return value to indicate an error, but you can set `errno'
 156    to 0 and check its value after calling `alarm', and this might tell you.
 157    The signal may come late due to processor scheduling.  */
 158 extern unsigned int alarm __P ((unsigned int __seconds));
 159
 160 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 161    and is not ignored.  The function returns the number of seconds less
 162    than SECONDS which it actually slept (thus zero if it slept the full time).
 163    If a signal handler does a `longjmp' or modifies the handling of the
 164    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 165    signal afterwards is undefined.  There is no return value to indicate
 166    error, but if `sleep' returns SECONDS, it probably didn't work.  */
 167 extern unsigned int sleep __P ((unsigned int __seconds));
 168
 169
 170 /* Suspend the process until a signal arrives.
 171    This always returns -1 and sets `errno' to EINTR.  */
 172 extern int pause __P ((void));
 173
 174
 175 /* Change the owner and group of FILE.  */
 176 extern int __chown __P ((__const char *__file,
 177                          __uid_t __owner, __gid_t __group));
 178 extern int chown __P ((__const char *__file,
 179                        __uid_t __owner, __gid_t __group));
 180
 181 #ifdef  __USE_BSD
 182 /* Change the owner and group of the file that FD is open on.  */
 183 extern int __fchown __P ((int __fd,
 184                           __uid_t __owner, __gid_t __group));
 185 extern int fchown __P ((int __fd,
 186                         __uid_t __owner, __gid_t __group));
 187 #endif /* Use BSD.  */
 188
 189 /* Change the process's working directory to PATH.  */
 190 extern int __chdir __P ((__const char *__path));
 191 extern int chdir __P ((__const char *__path));
 192
 193 #ifdef __USE_BSD
 194 /* Change the process's working directory to the one FD is open on.  */
 195 extern int fchdir __P ((int __fd));
 196 #endif
 197
 198 /* Get the pathname of the current working directory,
 199    and put it in SIZE bytes of BUF.  Returns NULL if the
 200    directory couldn't be determined or SIZE was too small.
 201    If successful, returns BUF.  In GNU, if BUF is NULL,
 202    an array is allocated with `malloc'; the array is SIZE
 203    bytes long, unless SIZE <= 0, in which case it is as
 204    big as necessary.  */
 205 extern char *getcwd __P ((char *__buf, size_t __size));
 206
 207 #ifdef  __USE_GNU
 208 /* Return a malloc'd string containing the current directory name.
 209    If the environment variable `PWD' is set, and its value is correct,
 210    that value is used.  */
 211 extern char *get_current_dir_name __P ((void));
 212 #endif
 213
 214 #ifdef  __USE_BSD
 215 /* Put the absolute pathname of the current working directory in BUF.
 216    If successful, return BUF.  If not, put an error message in
 217    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 218 extern char *getwd __P ((char *__buf));
 219 #endif
 220
 221
 222 /* Duplicate FD, returning a new file descriptor on the same file.  */
 223 extern int __dup __P ((int __fd));
 224 extern int dup __P ((int __fd));
 225
 226 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 227 extern int __dup2 __P ((int __fd, int __fd2));
 228 extern int dup2 __P ((int __fd, int __fd2));
 229
 230 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 231 extern char **__environ;
 232 extern char **environ;
 233
 234
 235 /* Replace the current process, executing PATH with arguments ARGV and
 236    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 237 extern int __execve __P ((__const char *__path, char *__const __argv[],
 238                           char *__const __envp[]));
 239 extern int execve __P ((__const char *__path, char *__const __argv[],
 240                         char *__const __envp[]));
 241
 242 #ifdef __USE_GNU
 243 /* Execute the file FD refers to, overlaying the running program image.
 244    ARGV and ENVP are passed to the new program, as for `execve'.  */
 245 extern int fexecve __P ((int __fd,
 246                          char *const __argv[], char *const __envp[]));
 247
 248 #endif
 249
 250
 251 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 252 extern int execv __P ((__const char *__path, char *__const __argv[]));
 253
 254 /* Execute PATH with all arguments after PATH until a NULL pointer,
 255    and the argument after that for environment.  */
 256 extern int execle __P ((__const char *__path, __const char *__arg,...));
 257
 258 /* Execute PATH with all arguments after PATH until
 259    a NULL pointer and environment from `environ'.  */
 260 extern int execl __P ((__const char *__path, __const char *__arg,...));
 261
 262 /* Execute FILE, searching in the `PATH' environment variable if it contains
 263    no slashes, with arguments ARGV and environment from `environ'.  */
 264 extern int execvp __P ((__const char *__file, char *__const __argv[]));
 265
 266 /* Execute FILE, searching in the `PATH' environment variable if
 267    it contains no slashes, with all arguments after FILE until a
 268    NULL pointer and environment from `environ'.  */
 269 extern int execlp __P ((__const char *__file, ...));
 270
 271
 272 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 273 extern void _exit __P ((int __status)) __attribute__ ((__noreturn__));
 274
 275
 276 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 277    the `_SC_*' symbols for the NAME argument to `sysconf';
 278    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 279 #include <confname.h>
 280
 281 /* Get file-specific configuration information about PATH.  */
 282 extern long int __pathconf __P ((__const char *__path, int __name));
 283 extern long int pathconf __P ((__const char *__path, int __name));
 284
 285 /* Get file-specific configuration about descriptor FD.  */
 286 extern long int __fpathconf __P ((int __fd, int __name));
 287 extern long int fpathconf __P ((int __fd, int __name));
 288
 289 /* Get the value of the system variable NAME.  */
 290 extern long int __sysconf __P ((int __name));
 291 extern long int sysconf __P ((int __name));
 292
 293 #ifdef  __USE_POSIX2
 294 /* Get the value of the string-valued system variable NAME.  */
 295 extern size_t confstr __P ((int __name, char *__buf, size_t __len));
 296 #endif
 297
 298
 299 /* Get the process ID of the calling process.  */
 300 extern __pid_t __getpid __P ((void));
 301 extern __pid_t getpid __P ((void));
 302
 303 /* Get the process ID of the calling process's parent.  */
 304 extern __pid_t __getppid __P ((void));
 305 extern __pid_t getppid __P ((void));
 306
 307 /* Get the process group ID of the calling process.  */
 308 extern __pid_t getpgrp __P ((void));
 309
 310 /* Set the process group ID of the process matching PID to PGID.
 311    If PID is zero, the current process's process group ID is set.
 312    If PGID is zero, the process ID of the process is used.  */
 313 extern int setpgid __P ((__pid_t __pid, __pid_t __pgid));
 314
 315 /* Get the process group ID of process PID.  */
 316 extern __pid_t __getpgid __P ((__pid_t __pid));
 317 #ifdef __USE_GNU
 318 extern __pid_t getpgid __P ((__pid_t __pid));
 319 #endif
 320
 321 #ifdef  __USE_BSD
 322 /* Another name for `setpgid'.  */
 323 extern int setpgrp __P ((__pid_t __pid, __pid_t __pgrp));
 324 #endif /* Use BSD.  */
 325
 326 /* Create a new session with the calling process as its leader.
 327    The process group IDs of the session and the calling process
 328    are set to the process ID of the calling process, which is returned.  */
 329 extern __pid_t __setsid __P ((void));
 330 extern __pid_t setsid __P ((void));
 331
 332 /* Get the real user ID of the calling process.  */
 333 extern __uid_t __getuid __P ((void));
 334 extern __uid_t getuid __P ((void));
 335
 336 /* Get the effective user ID of the calling process.  */
 337 extern __uid_t __geteuid __P ((void));
 338 extern __uid_t geteuid __P ((void));
 339
 340 /* Get the real group ID of the calling process.  */
 341 extern __gid_t __getgid __P ((void));
 342 extern __gid_t getgid __P ((void));
 343
 344 /* Get the effective group ID of the calling process.  */
 345 extern __gid_t __getegid __P ((void));
 346 extern __gid_t getegid __P ((void));
 347
 348 /* If SIZE is zero, return the number of supplementary groups
 349    the calling process is in.  Otherwise, fill in the group IDs
 350    of its supplementary groups in LIST and return the number written.  */
 351 extern int __getgroups __P ((int __size, __gid_t __list[]));
 352 extern int getgroups __P ((int __size, __gid_t __list[]));
 353
 354 /* Set the user ID of the calling process to UID.
 355    If the calling process is the super-user, set the real
 356    and effective user IDs, and the saved set-user-ID to UID;
 357    if not, the effective user ID is set to UID.  */
 358 extern int __setuid __P ((__uid_t __uid));
 359 extern int setuid __P ((__uid_t __uid));
 360
 361 #ifdef  __USE_BSD
 362 /* Set the real user ID of the calling process to RUID,
 363    and the effective user ID of the calling process to EUID.  */
 364 extern int __setreuid __P ((__uid_t __ruid, __uid_t __euid));
 365 extern int setreuid __P ((__uid_t __ruid, __uid_t __euid));
 366
 367 /* Set the effective user ID of the calling process to UID.  */
 368 extern int seteuid __P ((__uid_t __uid));
 369 #endif /* Use BSD.  */
 370
 371 /* Set the group ID of the calling process to GID.
 372    If the calling process is the super-user, set the real
 373    and effective group IDs, and the saved set-group-ID to GID;
 374    if not, the effective group ID is set to GID.  */
 375 extern int __setgid __P ((__gid_t __gid));
 376 extern int setgid __P ((__gid_t __gid));
 377
 378 #ifdef  __USE_BSD
 379 /* Set the real group ID of the calling process to RGID,
 380    and the effective group ID of the calling process to EGID.  */
 381 extern int __setregid __P ((__gid_t __rgid, __gid_t __egid));
 382 extern int setregid __P ((__gid_t __rgid, __gid_t __egid));
 383
 384 /* Set the effective group ID of the calling process to GID.  */
 385 extern int setegid __P ((__gid_t __gid));
 386 #endif /* Use BSD.  */
 387
 388
 389 /* Clone the calling process, creating an exact copy.
 390    Return -1 for errors, 0 to the new process,
 391    and the process ID of the new process to the old process.  */
 392 extern __pid_t __fork __P ((void));
 393 extern __pid_t fork __P ((void));
 394
 395 #ifdef  __USE_BSD
 396 /* Clone the calling process, but without copying the whole address space.
 397    The the calling process is suspended until the the new process exits or is
 398    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 399    and the process ID of the new process to the old process.  */
 400 extern __pid_t __vfork __P ((void));
 401 extern __pid_t vfork __P ((void));
 402 #endif /* Use BSD. */
 403
 404
 405 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 406    The returned storage is good only until the next call to this function.  */
 407 extern char *ttyname __P ((int __fd));
 408
 409 /* Return 1 if FD is a valid descriptor associated
 410    with a terminal, zero if not.  */
 411 extern int __isatty __P ((int __fd));
 412 extern int isatty __P ((int __fd));
 413
 414
 415 /* Make a link to FROM named TO.  */
 416 extern int __link __P ((__const char *__from, __const char *__to));
 417 extern int link __P ((__const char *__from, __const char *__to));
 418
 419 #ifdef  __USE_BSD
 420 /* Make a symbolic link to FROM named TO.  */
 421 extern int __symlink __P ((__const char *__from, __const char *__to));
 422 extern int symlink __P ((__const char *__from, __const char *__to));
 423
 424 /* Read the contents of the symbolic link PATH into no more than
 425    LEN bytes of BUF.  The contents are not null-terminated.
 426    Returns the number of characters read, or -1 for errors.  */
 427 extern int __readlink __P ((__const char *__path, char *__buf, size_t __len));
 428 extern int readlink __P ((__const char *__path, char *__buf, size_t __len));
 429 #endif /* Use BSD.  */
 430
 431 /* Remove the link NAME.  */
 432 extern int __unlink __P ((__const char *__name));
 433 extern int unlink __P ((__const char *__name));
 434
 435 /* Remove the directory PATH.  */
 436 extern int __rmdir __P ((__const char *__path));
 437 extern int rmdir __P ((__const char *__path));
 438
 439
 440 /* Return the foreground process group ID of FD.  */
 441 extern __pid_t tcgetpgrp __P ((int __fd));
 442
 443 /* Set the foreground process group ID of FD set PGRP_ID.  */
 444 extern int tcsetpgrp __P ((int __fd, __pid_t __pgrp_id));
 445
 446
 447 /* Return the login name of the user.  */
 448 extern char *getlogin __P ((void));
 449
 450 #ifdef  __USE_BSD
 451 /* Set the login name returned by `getlogin'.  */
 452 extern int setlogin __P ((__const char *__name));
 453 #endif
 454
 455
 456 #ifdef  __USE_POSIX2
 457 /* Process the arguments in ARGV (ARGC of them, minus
 458    the program name) for options given in OPTS.
 459
 460    If `opterr' is zero, no messages are generated
 461    for invalid options; it defaults to 1.
 462    `optind' is the current index into ARGV.
 463    `optarg' is the argument corresponding to the current option.
 464    Return the option character from OPTS just read.
 465    Return -1 when there are no more options.
 466    For unrecognized options, or options missing arguments,
 467    `optopt' is set to the option letter, and '?' is returned.
 468
 469    The OPTS string is a list of characters which are recognized option
 470    letters, optionally followed by colons, specifying that that letter
 471    takes an argument, to be placed in `optarg'.
 472
 473    If a letter in OPTS is followed by two colons, its argument is optional.
 474    This behavior is specific to the GNU `getopt'.
 475
 476    The argument `--' causes premature termination of argument scanning,
 477    explicitly telling `getopt' that there are no more options.
 478
 479    If OPTS begins with `--', then non-option arguments
 480    are treated as arguments to the option '\0'.
 481    This behavior is specific to the GNU `getopt'.  */
 482 extern int getopt __P ((int __argc, char *__const * __argv,
 483                         __const char *__opts));
 484 extern int opterr;
 485 extern int optind;
 486 extern int optopt;
 487 extern char *optarg;
 488 #endif
 489
 490
 491 #ifdef  __USE_BSD
 492
 493 /* Put the name of the current host in no more than LEN bytes of NAME.
 494    The result is null-terminated if LEN is large enough for the full
 495    name and the terminator.  */
 496 extern int __gethostname __P ((char *__name, size_t __len));
 497 extern int gethostname __P ((char *__name, size_t __len));
 498
 499 /* Set the name of the current host to NAME, which is LEN bytes long.
 500    This call is restricted to the super-user.  */
 501 extern int sethostname __P ((__const char *__name, size_t __len));
 502
 503 /* Return the current machine's Internet number.  */
 504 extern long int gethostid __P ((void));
 505
 506 /* Set the current machine's Internet number to ID.
 507    This call is restricted to the super-user.  */
 508 extern int sethostid __P ((long int __id));
 509
 510
 511 /* Return the number of bytes in a page.  This is the system's page size,
 512    which is not necessarily the same as the hardware page size.  */
 513 extern size_t __getpagesize __P ((void));
 514 extern size_t getpagesize __P ((void));
 515
 516
 517 /* Return the maximum number of file descriptors
 518    the current process could possibly have.  */
 519 extern int __getdtablesize __P ((void));
 520 extern int getdtablesize __P ((void));
 521
 522
 523 /* Truncate FILE to LENGTH bytes.  */
 524 extern int truncate __P ((__const char *__file, __off_t __length));
 525
 526 /* Truncate the file FD is open on to LENGTH bytes.  */
 527 extern int ftruncate __P ((int __fd, __off_t __length));
 528
 529
 530 /* Make all changes done to FD actually appear on disk.  */
 531 extern int fsync __P ((int __fd));
 532
 533 /* Make all changes done to all files actually appear on disk.  */
 534 extern int sync __P ((void));
 535
 536
 537 /* Revoke access permissions to all processes currently communicating
 538    with the control terminal, and then send a SIGHUP signal to the process
 539    group of the control terminal.  */
 540 extern int vhangup __P ((void));
 541
 542
 543 /* Turn accounting on if NAME is an existing file.  The system will then write
 544    a record for each process as it terminates, to this file.  If NAME is NULL,
 545    turn accounting off.  This call is restricted to the super-user.  */
 546 extern int acct __P ((__const char *__name));
 547
 548 /* Make PATH be the root directory (the starting point for absolute paths).
 549    This call is restricted to the super-user.  */
 550 extern int chroot __P ((__const char *__path));
 551
 552 /* Make the block special device PATH available to the system for swapping.
 553    This call is restricted to the super-user.  */
 554 extern int swapon __P ((__const char *__path));
 555
 556 /* Reboot or halt the system.  */
 557 extern int reboot __P ((int __howto));
 558
 559
 560 /* Successive calls return the shells listed in `/etc/shells'.  */
 561 extern char *getusershell __P ((void));
 562 extern void endusershell __P ((void)); /* Discard cached info.  */
 563 extern void setusershell __P ((void)); /* Rewind and re-read the file.  */
 564
 565
 566 /* Prompt with PROMPT and read a string from the terminal without echoing.
 567    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 568 extern char *getpass __P ((const char *__prompt));
 569
 570 /* Put the program in the background, and dissociate from the controlling
 571    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 572    redirects stdin, stdout, and stderr to /dev/null.  */
 573 extern int daemon __P ((int __nochdir, int __noclose));
 574
 575 #endif /* Use BSD.  */
 576
 577
 578 #ifdef __USE_MISC
 579
 580 /* Generate a unique temporary file name from TEMPLATE.
 581    The last six characters of TEMPLATE must be "XXXXXX";
 582    they are replaced with a string that makes the file name unique.
 583    Returns TEMPLATE, or a null pointer if it cannot get a unique file name.  */
 584 extern char *mktemp __P ((char *__template));
 585
 586 /* Generate a unique temporary file name from TEMPLATE.
 587    The last six characters of TEMPLATE must be "XXXXXX";
 588    they are replaced with a string that makes the filename unique.
 589    Returns a file descriptor open on the file for reading and writing,
 590    or -1 if it cannot create a uniquely-named file.  */
 591 extern int mkstemp __P ((char *__template));
 592
 593
 594 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 595    This is completely system-dependent, and not often useful.
 596
 597    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 598    for errors; in many systems you cannot pass arguments or get return
 599    values for all system calls (`pipe', `fork', and `getppid' typically
 600    among them).
 601
 602    In Mach, all system calls take normal arguments and always return an
 603    error code (zero for success).  */
 604 extern int syscall __P ((int __sysno, ...));
 605
 606 #endif  /* Use misc.  */
 607
 608
 609 #if defined (__USE_MISC) && !defined (F_LOCK)
 610 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
 611    files consistent.  Some systems have them there and some here, and some
 612    software depends on the macros being defined without including both.  */
 613
 614 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 615    LEN is always relative to the current file position.
 616    The CMD argument is one of the following.  */
 617
 618 #define F_ULOCK 0       /* Unlock a previously locked region.  */
 619 #define F_LOCK  1       /* Lock a region for exclusive use.  */
 620 #define F_TLOCK 2       /* Test and lock a region for exclusive use.  */
 621 #define F_TEST  3       /* Test a region for other processes locks.  */
 622
 623 extern int lockf __P ((int __fd, int __cmd, __off_t __len));
 624 #endif /* Use misc and F_LOCK not already defined.  */
 625
 626
 627 #ifdef __USE_GNU
 628
 629 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
 630    set to EINTR.  */
 631
 632 #define TEMP_FAILURE_RETRY(expression) \
 633   ({ long int __result;                                                       \
 634        do __result = (long int) (expression);                                 \
 635        while (__result == -1L && errno == EINTR);                             \
 636        __result; })
 637
 638 #endif
 639
 640 __END_DECLS
 641
 642 #endif /* unistd.h  */