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 using the real UID and real GID.  */
 111 extern int __access __P ((__const char *__name, int __type));
 112 extern int access __P ((__const char *__name, int __type));
 113
 114 #ifdef __USE_GNU
 115 /* Test for access to NAME using the effective UID and GID
 116    (as normal file operations use).  */
 117 extern int euidaccess __P ((__const char *__name, int __type));
 118 #endif
 119
 120
 121 /* Values for the WHENCE argument to lseek.  */
 122 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 123 #define SEEK_SET        0       /* Seek from beginning of file.  */
 124 #define SEEK_CUR        1       /* Seek from current position.  */
 125 #define SEEK_END        2       /* Seek from end of file.  */
 126 #endif
 127
 128 #if defined (__USE_BSD) && !defined (L_SET)
 129 /* Old BSD names for the same constants; just for compatibility.  */
 130 #define L_SET           SEEK_SET
 131 #define L_INCR          SEEK_CUR
 132 #define L_XTND          SEEK_END
 133 #endif
 134
 135
 136 /* Move FD's file position to OFFSET bytes from the
 137    beginning of the file (if WHENCE is SEEK_SET),
 138    the current position (if WHENCE is SEEK_CUR),
 139    or the end of the file (if WHENCE is SEEK_END).
 140    Return the new file position.  */
 141 extern __off_t __lseek __P ((int __fd, __off_t __offset, int __whence));
 142 extern __off_t lseek __P ((int __fd, __off_t __offset, int __whence));
 143
 144 /* Close the file descriptor FD.  */
 145 extern int __close __P ((int __fd));
 146 extern int close __P ((int __fd));
 147
 148 /* Read NBYTES into BUF from FD.  Return the
 149    number read, -1 for errors or 0 for EOF.  */
 150 extern ssize_t __read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 151 extern ssize_t read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 152
 153 /* Write N bytes of BUF to FD.  Return the number written, or -1.  */
 154 extern ssize_t __write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 155 extern ssize_t write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 156
 157
 158 /* Create a one-way communication channel (pipe).
 159    If successul, two file descriptors are stored in PIPEDES;
 160    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 161    Returns 0 if successful, -1 if not.  */
 162 extern int __pipe __P ((int __pipedes[2]));
 163 extern int pipe __P ((int __pipedes[2]));
 164
 165 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 166    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 167    The function returns the number of seconds remaining until the last
 168    alarm scheduled would have signaled, or zero if there wasn't one.
 169    There is no return value to indicate an error, but you can set `errno'
 170    to 0 and check its value after calling `alarm', and this might tell you.
 171    The signal may come late due to processor scheduling.  */
 172 extern unsigned int alarm __P ((unsigned int __seconds));
 173
 174 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 175    and is not ignored.  The function returns the number of seconds less
 176    than SECONDS which it actually slept (thus zero if it slept the full time).
 177    If a signal handler does a `longjmp' or modifies the handling of the
 178    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 179    signal afterwards is undefined.  There is no return value to indicate
 180    error, but if `sleep' returns SECONDS, it probably didn't work.  */
 181 extern unsigned int sleep __P ((unsigned int __seconds));
 182
 183
 184 /* Suspend the process until a signal arrives.
 185    This always returns -1 and sets `errno' to EINTR.  */
 186 extern int pause __P ((void));
 187
 188
 189 /* Change the owner and group of FILE.  */
 190 extern int __chown __P ((__const char *__file,
 191                          __uid_t __owner, __gid_t __group));
 192 extern int chown __P ((__const char *__file,
 193                        __uid_t __owner, __gid_t __group));
 194
 195 #ifdef  __USE_BSD
 196 /* Change the owner and group of the file that FD is open on.  */
 197 extern int __fchown __P ((int __fd,
 198                           __uid_t __owner, __gid_t __group));
 199 extern int fchown __P ((int __fd,
 200                         __uid_t __owner, __gid_t __group));
 201 #endif /* Use BSD.  */
 202
 203 /* Change the process's working directory to PATH.  */
 204 extern int __chdir __P ((__const char *__path));
 205 extern int chdir __P ((__const char *__path));
 206
 207 #ifdef __USE_BSD
 208 /* Change the process's working directory to the one FD is open on.  */
 209 extern int fchdir __P ((int __fd));
 210 #endif
 211
 212 /* Get the pathname of the current working directory,
 213    and put it in SIZE bytes of BUF.  Returns NULL if the
 214    directory couldn't be determined or SIZE was too small.
 215    If successful, returns BUF.  In GNU, if BUF is NULL,
 216    an array is allocated with `malloc'; the array is SIZE
 217    bytes long, unless SIZE <= 0, in which case it is as
 218    big as necessary.  */
 219 extern char *__getcwd __P ((char *__buf, size_t __size));
 220 extern char *getcwd __P ((char *__buf, size_t __size));
 221
 222 #ifdef  __USE_GNU
 223 /* Return a malloc'd string containing the current directory name.
 224    If the environment variable `PWD' is set, and its value is correct,
 225    that value is used.  */
 226 extern char *get_current_dir_name __P ((void));
 227 #endif
 228
 229 #ifdef  __USE_BSD
 230 /* Put the absolute pathname of the current working directory in BUF.
 231    If successful, return BUF.  If not, put an error message in
 232    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 233 extern char *getwd __P ((char *__buf));
 234 #endif
 235
 236
 237 /* Duplicate FD, returning a new file descriptor on the same file.  */
 238 extern int __dup __P ((int __fd));
 239 extern int dup __P ((int __fd));
 240
 241 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 242 extern int __dup2 __P ((int __fd, int __fd2));
 243 extern int dup2 __P ((int __fd, int __fd2));
 244
 245 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 246 extern char **__environ;
 247 extern char **environ;
 248
 249
 250 /* Replace the current process, executing PATH with arguments ARGV and
 251    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 252 extern int __execve __P ((__const char *__path, char *__const __argv[],
 253                           char *__const __envp[]));
 254 extern int execve __P ((__const char *__path, char *__const __argv[],
 255                         char *__const __envp[]));
 256
 257 #ifdef __USE_GNU
 258 /* Execute the file FD refers to, overlaying the running program image.
 259    ARGV and ENVP are passed to the new program, as for `execve'.  */
 260 extern int fexecve __P ((int __fd,
 261                          char *const __argv[], char *const __envp[]));
 262
 263 #endif
 264
 265
 266 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 267 extern int execv __P ((__const char *__path, char *__const __argv[]));
 268
 269 /* Execute PATH with all arguments after PATH until a NULL pointer,
 270    and the argument after that for environment.  */
 271 extern int execle __P ((__const char *__path, __const char *__arg,...));
 272
 273 /* Execute PATH with all arguments after PATH until
 274    a NULL pointer and environment from `environ'.  */
 275 extern int execl __P ((__const char *__path, __const char *__arg,...));
 276
 277 /* Execute FILE, searching in the `PATH' environment variable if it contains
 278    no slashes, with arguments ARGV and environment from `environ'.  */
 279 extern int execvp __P ((__const char *__file, char *__const __argv[]));
 280
 281 /* Execute FILE, searching in the `PATH' environment variable if
 282    it contains no slashes, with all arguments after FILE until a
 283    NULL pointer and environment from `environ'.  */
 284 extern int execlp __P ((__const char *__file, ...));
 285
 286
 287 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 288 extern void _exit __P ((int __status)) __attribute__ ((__noreturn__));
 289
 290
 291 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 292    the `_SC_*' symbols for the NAME argument to `sysconf';
 293    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 294 #include <confname.h>
 295
 296 /* Get file-specific configuration information about PATH.  */
 297 extern long int __pathconf __P ((__const char *__path, int __name));
 298 extern long int pathconf __P ((__const char *__path, int __name));
 299
 300 /* Get file-specific configuration about descriptor FD.  */
 301 extern long int __fpathconf __P ((int __fd, int __name));
 302 extern long int fpathconf __P ((int __fd, int __name));
 303
 304 /* Get the value of the system variable NAME.  */
 305 extern long int __sysconf __P ((int __name));
 306 extern long int sysconf __P ((int __name));
 307
 308 #ifdef  __USE_POSIX2
 309 /* Get the value of the string-valued system variable NAME.  */
 310 extern size_t confstr __P ((int __name, char *__buf, size_t __len));
 311 #endif
 312
 313
 314 /* Get the process ID of the calling process.  */
 315 extern __pid_t __getpid __P ((void));
 316 extern __pid_t getpid __P ((void));
 317
 318 /* Get the process ID of the calling process's parent.  */
 319 extern __pid_t __getppid __P ((void));
 320 extern __pid_t getppid __P ((void));
 321
 322 /* Get the process group ID of the calling process.  */
 323 extern __pid_t getpgrp __P ((void));
 324
 325 /* Set the process group ID of the process matching PID to PGID.
 326    If PID is zero, the current process's process group ID is set.
 327    If PGID is zero, the process ID of the process is used.  */
 328 extern int setpgid __P ((__pid_t __pid, __pid_t __pgid));
 329
 330 /* Get the process group ID of process PID.  */
 331 extern __pid_t __getpgid __P ((__pid_t __pid));
 332 #ifdef __USE_GNU
 333 extern __pid_t getpgid __P ((__pid_t __pid));
 334 #endif
 335
 336 #ifdef  __USE_BSD
 337 /* Another name for `setpgid'.  */
 338 extern int setpgrp __P ((__pid_t __pid, __pid_t __pgrp));
 339 #endif /* Use BSD.  */
 340
 341 /* Create a new session with the calling process as its leader.
 342    The process group IDs of the session and the calling process
 343    are set to the process ID of the calling process, which is returned.  */
 344 extern __pid_t __setsid __P ((void));
 345 extern __pid_t setsid __P ((void));
 346
 347 #ifdef __USE_GNU
 348 /* Return the session ID of the given process.  */
 349 extern __pid_t getsid __P ((__pid_t));
 350 #endif
 351
 352 /* Get the real user ID of the calling process.  */
 353 extern __uid_t __getuid __P ((void));
 354 extern __uid_t getuid __P ((void));
 355
 356 /* Get the effective user ID of the calling process.  */
 357 extern __uid_t __geteuid __P ((void));
 358 extern __uid_t geteuid __P ((void));
 359
 360 /* Get the real group ID of the calling process.  */
 361 extern __gid_t __getgid __P ((void));
 362 extern __gid_t getgid __P ((void));
 363
 364 /* Get the effective group ID of the calling process.  */
 365 extern __gid_t __getegid __P ((void));
 366 extern __gid_t getegid __P ((void));
 367
 368 /* If SIZE is zero, return the number of supplementary groups
 369    the calling process is in.  Otherwise, fill in the group IDs
 370    of its supplementary groups in LIST and return the number written.  */
 371 extern int __getgroups __P ((int __size, __gid_t __list[]));
 372 extern int getgroups __P ((int __size, __gid_t __list[]));
 373
 374 #ifdef  __USE_GNU
 375 /* Return nonzero iff the calling process is in group GID.  */
 376 extern int __group_member __P ((__gid_t __gid));
 377 extern int group_member __P ((__gid_t __gid));
 378 #endif
 379
 380 /* Set the user ID of the calling process to UID.
 381    If the calling process is the super-user, set the real
 382    and effective user IDs, and the saved set-user-ID to UID;
 383    if not, the effective user ID is set to UID.  */
 384 extern int __setuid __P ((__uid_t __uid));
 385 extern int setuid __P ((__uid_t __uid));
 386
 387 #ifdef  __USE_BSD
 388 /* Set the real user ID of the calling process to RUID,
 389    and the effective user ID of the calling process to EUID.  */
 390 extern int __setreuid __P ((__uid_t __ruid, __uid_t __euid));
 391 extern int setreuid __P ((__uid_t __ruid, __uid_t __euid));
 392
 393 /* Set the effective user ID of the calling process to UID.  */
 394 extern int seteuid __P ((__uid_t __uid));
 395 #endif /* Use BSD.  */
 396
 397 /* Set the group ID of the calling process to GID.
 398    If the calling process is the super-user, set the real
 399    and effective group IDs, and the saved set-group-ID to GID;
 400    if not, the effective group ID is set to GID.  */
 401 extern int __setgid __P ((__gid_t __gid));
 402 extern int setgid __P ((__gid_t __gid));
 403
 404 #ifdef  __USE_BSD
 405 /* Set the real group ID of the calling process to RGID,
 406    and the effective group ID of the calling process to EGID.  */
 407 extern int __setregid __P ((__gid_t __rgid, __gid_t __egid));
 408 extern int setregid __P ((__gid_t __rgid, __gid_t __egid));
 409
 410 /* Set the effective group ID of the calling process to GID.  */
 411 extern int setegid __P ((__gid_t __gid));
 412 #endif /* Use BSD.  */
 413
 414
 415 /* Clone the calling process, creating an exact copy.
 416    Return -1 for errors, 0 to the new process,
 417    and the process ID of the new process to the old process.  */
 418 extern __pid_t __fork __P ((void));
 419 extern __pid_t fork __P ((void));
 420
 421 #ifdef  __USE_BSD
 422 /* Clone the calling process, but without copying the whole address space.
 423    The the calling process is suspended until the the new process exits or is
 424    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 425    and the process ID of the new process to the old process.  */
 426 extern __pid_t __vfork __P ((void));
 427 extern __pid_t vfork __P ((void));
 428 #endif /* Use BSD. */
 429
 430
 431 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 432    The returned storage is good only until the next call to this function.  */
 433 extern char *ttyname __P ((int __fd));
 434 #ifdef __USE_REENTRANT
 435 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 436    open on in BUF.  Return 0 on success, -1 otherwise.  */
 437 extern int ttyname_r __P ((int __fd, char *__buf, int __buflen));
 438 #endif
 439
 440 /* Return 1 if FD is a valid descriptor associated
 441    with a terminal, zero if not.  */
 442 extern int __isatty __P ((int __fd));
 443 extern int isatty __P ((int __fd));
 444
 445 #ifdef __USE_BSD
 446 /* Return the index into the active-logins file (utmp) for
 447    the controlling terminal.  */
 448 extern int ttyslot __P ((void));
 449 #endif
 450
 451
 452 /* Make a link to FROM named TO.  */
 453 extern int __link __P ((__const char *__from, __const char *__to));
 454 extern int link __P ((__const char *__from, __const char *__to));
 455
 456 #ifdef  __USE_BSD
 457 /* Make a symbolic link to FROM named TO.  */
 458 extern int __symlink __P ((__const char *__from, __const char *__to));
 459 extern int symlink __P ((__const char *__from, __const char *__to));
 460
 461 /* Read the contents of the symbolic link PATH into no more than
 462    LEN bytes of BUF.  The contents are not null-terminated.
 463    Returns the number of characters read, or -1 for errors.  */
 464 extern int __readlink __P ((__const char *__path, char *__buf, size_t __len));
 465 extern int readlink __P ((__const char *__path, char *__buf, size_t __len));
 466 #endif /* Use BSD.  */
 467
 468 /* Remove the link NAME.  */
 469 extern int __unlink __P ((__const char *__name));
 470 extern int unlink __P ((__const char *__name));
 471
 472 /* Remove the directory PATH.  */
 473 extern int __rmdir __P ((__const char *__path));
 474 extern int rmdir __P ((__const char *__path));
 475
 476
 477 /* Return the foreground process group ID of FD.  */
 478 extern __pid_t tcgetpgrp __P ((int __fd));
 479
 480 /* Set the foreground process group ID of FD set PGRP_ID.  */
 481 extern int tcsetpgrp __P ((int __fd, __pid_t __pgrp_id));
 482
 483
 484 /* Return the login name of the user.  */
 485 extern char *getlogin __P ((void));
 486
 487 #ifdef  __USE_BSD
 488 /* Set the login name returned by `getlogin'.  */
 489 extern int setlogin __P ((__const char *__name));
 490 #endif
 491
 492
 493 #ifdef  __USE_POSIX2
 494 /* Process the arguments in ARGV (ARGC of them, minus
 495    the program name) for options given in OPTS.
 496
 497    If `opterr' is zero, no messages are generated
 498    for invalid options; it defaults to 1.
 499    `optind' is the current index into ARGV.
 500    `optarg' is the argument corresponding to the current option.
 501    Return the option character from OPTS just read.
 502    Return -1 when there are no more options.
 503    For unrecognized options, or options missing arguments,
 504    `optopt' is set to the option letter, and '?' is returned.
 505
 506    The OPTS string is a list of characters which are recognized option
 507    letters, optionally followed by colons, specifying that that letter
 508    takes an argument, to be placed in `optarg'.
 509
 510    If a letter in OPTS is followed by two colons, its argument is optional.
 511    This behavior is specific to the GNU `getopt'.
 512
 513    The argument `--' causes premature termination of argument scanning,
 514    explicitly telling `getopt' that there are no more options.
 515
 516    If OPTS begins with `--', then non-option arguments
 517    are treated as arguments to the option '\0'.
 518    This behavior is specific to the GNU `getopt'.  */
 519 extern int getopt __P ((int __argc, char *__const * __argv,
 520                         __const char *__opts));
 521 extern int opterr;
 522 extern int optind;
 523 extern int optopt;
 524 extern char *optarg;
 525 #endif
 526
 527
 528 #ifdef  __USE_BSD
 529
 530 /* Put the name of the current host in no more than LEN bytes of NAME.
 531    The result is null-terminated if LEN is large enough for the full
 532    name and the terminator.  */
 533 extern int __gethostname __P ((char *__name, size_t __len));
 534 extern int gethostname __P ((char *__name, size_t __len));
 535
 536 /* Set the name of the current host to NAME, which is LEN bytes long.
 537    This call is restricted to the super-user.  */
 538 extern int sethostname __P ((__const char *__name, size_t __len));
 539
 540 /* Return the current machine's Internet number.  */
 541 extern long int gethostid __P ((void));
 542
 543 /* Set the current machine's Internet number to ID.
 544    This call is restricted to the super-user.  */
 545 extern int sethostid __P ((long int __id));
 546
 547
 548 /* Return the number of bytes in a page.  This is the system's page size,
 549    which is not necessarily the same as the hardware page size.  */
 550 extern size_t __getpagesize __P ((void));
 551 extern size_t getpagesize __P ((void));
 552
 553
 554 /* Return the maximum number of file descriptors
 555    the current process could possibly have.  */
 556 extern int __getdtablesize __P ((void));
 557 extern int getdtablesize __P ((void));
 558
 559
 560 /* Truncate FILE to LENGTH bytes.  */
 561 extern int truncate __P ((__const char *__file, __off_t __length));
 562
 563 /* Truncate the file FD is open on to LENGTH bytes.  */
 564 extern int ftruncate __P ((int __fd, __off_t __length));
 565
 566
 567 /* Make all changes done to FD actually appear on disk.  */
 568 extern int fsync __P ((int __fd));
 569
 570 /* Make all changes done to all files actually appear on disk.  */
 571 extern int sync __P ((void));
 572
 573
 574 /* Revoke access permissions to all processes currently communicating
 575    with the control terminal, and then send a SIGHUP signal to the process
 576    group of the control terminal.  */
 577 extern int vhangup __P ((void));
 578
 579 /* Revoke the access of all descriptors currently open on FILE.  */
 580 extern int revoke __P ((const char *__file));
 581
 582
 583 /* Enable statistical profiling, writing samples of the PC into at most
 584    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 585    is enabled, the system examines the user PC and increments
 586    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 587    disable profiling.  Returns zero on success, -1 on error.  */
 588 extern int profil __P ((unsigned short int *__sample_buffer, size_t __size,
 589                         size_t __offset, unsigned int __scale));
 590
 591
 592 /* Turn accounting on if NAME is an existing file.  The system will then write
 593    a record for each process as it terminates, to this file.  If NAME is NULL,
 594    turn accounting off.  This call is restricted to the super-user.  */
 595 extern int acct __P ((__const char *__name));
 596
 597 /* Make PATH be the root directory (the starting point for absolute paths).
 598    This call is restricted to the super-user.  */
 599 extern int chroot __P ((__const char *__path));
 600
 601 /* Make the block special device PATH available to the system for swapping.
 602    This call is restricted to the super-user.  */
 603 extern int swapon __P ((__const char *__path));
 604
 605 /* Reboot or halt the system.  */
 606 extern int reboot __P ((int __howto));
 607
 608
 609 /* Successive calls return the shells listed in `/etc/shells'.  */
 610 extern char *getusershell __P ((void));
 611 extern void endusershell __P ((void)); /* Discard cached info.  */
 612 extern void setusershell __P ((void)); /* Rewind and re-read the file.  */
 613
 614
 615 /* Prompt with PROMPT and read a string from the terminal without echoing.
 616    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 617 extern char *getpass __P ((const char *__prompt));
 618
 619 /* Put the program in the background, and dissociate from the controlling
 620    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 621    redirects stdin, stdout, and stderr to /dev/null.  */
 622 extern int daemon __P ((int __nochdir, int __noclose));
 623
 624 #endif /* Use BSD.  */
 625
 626
 627 #ifdef __USE_MISC
 628
 629 /* Generate a unique temporary file name from TEMPLATE.
 630    The last six characters of TEMPLATE must be "XXXXXX";
 631    they are replaced with a string that makes the file name unique.
 632    Returns TEMPLATE, or a null pointer if it cannot get a unique file name.  */
 633 extern char *mktemp __P ((char *__template));
 634
 635 /* Generate a unique temporary file name from TEMPLATE.
 636    The last six characters of TEMPLATE must be "XXXXXX";
 637    they are replaced with a string that makes the filename unique.
 638    Returns a file descriptor open on the file for reading and writing,
 639    or -1 if it cannot create a uniquely-named file.  */
 640 extern int mkstemp __P ((char *__template));
 641
 642
 643 /* Set the end of accessible data space (aka "the break") to ADDR.
 644    Returns zero on success and -1 for errors (with errno set).  */
 645 extern int __brk __P ((__ptr_t __addr));
 646 extern int brk __P ((__ptr_t __addr));
 647
 648 #define __need_ptrdiff_t
 649 #include <stddef.h>
 650
 651 /* Increase or decrease the end of accessible data space by DELTA bytes.
 652    If successful, returns the address the previous end of data space
 653    (i.e. the beginning of the new space, if DELTA > 0);
 654    returns (void *) -1 for errors (with errno set).  */
 655 extern __ptr_t __sbrk __P ((ptrdiff_t __delta));
 656 extern __ptr_t sbrk __P ((ptrdiff_t __delta));
 657
 658
 659 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 660    This is completely system-dependent, and not often useful.
 661
 662    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 663    for errors; in many systems you cannot pass arguments or get return
 664    values for all system calls (`pipe', `fork', and `getppid' typically
 665    among them).
 666
 667    In Mach, all system calls take normal arguments and always return an
 668    error code (zero for success).  */
 669 extern int syscall __P ((int __sysno, ...));
 670
 671 #endif  /* Use misc.  */
 672
 673
 674 #if defined (__USE_MISC) && !defined (F_LOCK)
 675 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
 676    files consistent.  Some systems have them there and some here, and some
 677    software depends on the macros being defined without including both.  */
 678
 679 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 680    LEN is always relative to the current file position.
 681    The CMD argument is one of the following.  */
 682
 683 #define F_ULOCK 0       /* Unlock a previously locked region.  */
 684 #define F_LOCK  1       /* Lock a region for exclusive use.  */
 685 #define F_TLOCK 2       /* Test and lock a region for exclusive use.  */
 686 #define F_TEST  3       /* Test a region for other processes locks.  */
 687
 688 extern int lockf __P ((int __fd, int __cmd, __off_t __len));
 689 #endif /* Use misc and F_LOCK not already defined.  */
 690
 691
 692 #ifdef __USE_GNU
 693
 694 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
 695    set to EINTR.  */
 696
 697 #define TEMP_FAILURE_RETRY(expression) \
 698   ({ long int __result;                                                       \
 699        do __result = (long int) (expression);                                 \
 700        while (__result == -1L && errno == EINTR);                             \
 701        __result; })
 702
 703 #endif
 704
 705 __END_DECLS
 706
 707 #endif /* unistd.h  */