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 /* Get the real user ID of the calling process.  */
 348 extern __uid_t __getuid __P ((void));
 349 extern __uid_t getuid __P ((void));
 350
 351 /* Get the effective user ID of the calling process.  */
 352 extern __uid_t __geteuid __P ((void));
 353 extern __uid_t geteuid __P ((void));
 354
 355 /* Get the real group ID of the calling process.  */
 356 extern __gid_t __getgid __P ((void));
 357 extern __gid_t getgid __P ((void));
 358
 359 /* Get the effective group ID of the calling process.  */
 360 extern __gid_t __getegid __P ((void));
 361 extern __gid_t getegid __P ((void));
 362
 363 /* If SIZE is zero, return the number of supplementary groups
 364    the calling process is in.  Otherwise, fill in the group IDs
 365    of its supplementary groups in LIST and return the number written.  */
 366 extern int __getgroups __P ((int __size, __gid_t __list[]));
 367 extern int getgroups __P ((int __size, __gid_t __list[]));
 368
 369 #ifdef  __USE_GNU
 370 /* Return nonzero iff the calling process is in group GID.  */
 371 extern int __group_member __P ((__gid_t __gid));
 372 extern int group_member __P ((__gid_t __gid));
 373 #endif
 374
 375 /* Set the user ID of the calling process to UID.
 376    If the calling process is the super-user, set the real
 377    and effective user IDs, and the saved set-user-ID to UID;
 378    if not, the effective user ID is set to UID.  */
 379 extern int __setuid __P ((__uid_t __uid));
 380 extern int setuid __P ((__uid_t __uid));
 381
 382 #ifdef  __USE_BSD
 383 /* Set the real user ID of the calling process to RUID,
 384    and the effective user ID of the calling process to EUID.  */
 385 extern int __setreuid __P ((__uid_t __ruid, __uid_t __euid));
 386 extern int setreuid __P ((__uid_t __ruid, __uid_t __euid));
 387
 388 /* Set the effective user ID of the calling process to UID.  */
 389 extern int seteuid __P ((__uid_t __uid));
 390 #endif /* Use BSD.  */
 391
 392 /* Set the group ID of the calling process to GID.
 393    If the calling process is the super-user, set the real
 394    and effective group IDs, and the saved set-group-ID to GID;
 395    if not, the effective group ID is set to GID.  */
 396 extern int __setgid __P ((__gid_t __gid));
 397 extern int setgid __P ((__gid_t __gid));
 398
 399 #ifdef  __USE_BSD
 400 /* Set the real group ID of the calling process to RGID,
 401    and the effective group ID of the calling process to EGID.  */
 402 extern int __setregid __P ((__gid_t __rgid, __gid_t __egid));
 403 extern int setregid __P ((__gid_t __rgid, __gid_t __egid));
 404
 405 /* Set the effective group ID of the calling process to GID.  */
 406 extern int setegid __P ((__gid_t __gid));
 407 #endif /* Use BSD.  */
 408
 409
 410 /* Clone the calling process, creating an exact copy.
 411    Return -1 for errors, 0 to the new process,
 412    and the process ID of the new process to the old process.  */
 413 extern __pid_t __fork __P ((void));
 414 extern __pid_t fork __P ((void));
 415
 416 #ifdef  __USE_BSD
 417 /* Clone the calling process, but without copying the whole address space.
 418    The the calling process is suspended until the the new process exits or is
 419    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 420    and the process ID of the new process to the old process.  */
 421 extern __pid_t __vfork __P ((void));
 422 extern __pid_t vfork __P ((void));
 423 #endif /* Use BSD. */
 424
 425
 426 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 427    The returned storage is good only until the next call to this function.  */
 428 extern char *ttyname __P ((int __fd));
 429 #ifdef __USE_REENTRANT
 430 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 431    open on in BUF.  Return 0 on success, -1 otherwise.  */
 432 extern int ttyname_r __P ((int __fd, char *__buf, int __buflen));
 433 #endif
 434
 435 /* Return 1 if FD is a valid descriptor associated
 436    with a terminal, zero if not.  */
 437 extern int __isatty __P ((int __fd));
 438 extern int isatty __P ((int __fd));
 439
 440 #ifdef __USE_BSD
 441 /* Return the index into the active-logins file (utmp) for
 442    the controlling terminal.  */
 443 extern int ttyslot __P ((void));
 444 #endif
 445
 446
 447 /* Make a link to FROM named TO.  */
 448 extern int __link __P ((__const char *__from, __const char *__to));
 449 extern int link __P ((__const char *__from, __const char *__to));
 450
 451 #ifdef  __USE_BSD
 452 /* Make a symbolic link to FROM named TO.  */
 453 extern int __symlink __P ((__const char *__from, __const char *__to));
 454 extern int symlink __P ((__const char *__from, __const char *__to));
 455
 456 /* Read the contents of the symbolic link PATH into no more than
 457    LEN bytes of BUF.  The contents are not null-terminated.
 458    Returns the number of characters read, or -1 for errors.  */
 459 extern int __readlink __P ((__const char *__path, char *__buf, size_t __len));
 460 extern int readlink __P ((__const char *__path, char *__buf, size_t __len));
 461 #endif /* Use BSD.  */
 462
 463 /* Remove the link NAME.  */
 464 extern int __unlink __P ((__const char *__name));
 465 extern int unlink __P ((__const char *__name));
 466
 467 /* Remove the directory PATH.  */
 468 extern int __rmdir __P ((__const char *__path));
 469 extern int rmdir __P ((__const char *__path));
 470
 471
 472 /* Return the foreground process group ID of FD.  */
 473 extern __pid_t tcgetpgrp __P ((int __fd));
 474
 475 /* Set the foreground process group ID of FD set PGRP_ID.  */
 476 extern int tcsetpgrp __P ((int __fd, __pid_t __pgrp_id));
 477
 478
 479 /* Return the login name of the user.  */
 480 extern char *getlogin __P ((void));
 481
 482 #ifdef  __USE_BSD
 483 /* Set the login name returned by `getlogin'.  */
 484 extern int setlogin __P ((__const char *__name));
 485 #endif
 486
 487
 488 #ifdef  __USE_POSIX2
 489 /* Process the arguments in ARGV (ARGC of them, minus
 490    the program name) for options given in OPTS.
 491
 492    If `opterr' is zero, no messages are generated
 493    for invalid options; it defaults to 1.
 494    `optind' is the current index into ARGV.
 495    `optarg' is the argument corresponding to the current option.
 496    Return the option character from OPTS just read.
 497    Return -1 when there are no more options.
 498    For unrecognized options, or options missing arguments,
 499    `optopt' is set to the option letter, and '?' is returned.
 500
 501    The OPTS string is a list of characters which are recognized option
 502    letters, optionally followed by colons, specifying that that letter
 503    takes an argument, to be placed in `optarg'.
 504
 505    If a letter in OPTS is followed by two colons, its argument is optional.
 506    This behavior is specific to the GNU `getopt'.
 507
 508    The argument `--' causes premature termination of argument scanning,
 509    explicitly telling `getopt' that there are no more options.
 510
 511    If OPTS begins with `--', then non-option arguments
 512    are treated as arguments to the option '\0'.
 513    This behavior is specific to the GNU `getopt'.  */
 514 extern int getopt __P ((int __argc, char *__const * __argv,
 515                         __const char *__opts));
 516 extern int opterr;
 517 extern int optind;
 518 extern int optopt;
 519 extern char *optarg;
 520 #endif
 521
 522
 523 #ifdef  __USE_BSD
 524
 525 /* Put the name of the current host in no more than LEN bytes of NAME.
 526    The result is null-terminated if LEN is large enough for the full
 527    name and the terminator.  */
 528 extern int __gethostname __P ((char *__name, size_t __len));
 529 extern int gethostname __P ((char *__name, size_t __len));
 530
 531 /* Set the name of the current host to NAME, which is LEN bytes long.
 532    This call is restricted to the super-user.  */
 533 extern int sethostname __P ((__const char *__name, size_t __len));
 534
 535 /* Return the current machine's Internet number.  */
 536 extern long int gethostid __P ((void));
 537
 538 /* Set the current machine's Internet number to ID.
 539    This call is restricted to the super-user.  */
 540 extern int sethostid __P ((long int __id));
 541
 542
 543 /* Return the number of bytes in a page.  This is the system's page size,
 544    which is not necessarily the same as the hardware page size.  */
 545 extern size_t __getpagesize __P ((void));
 546 extern size_t getpagesize __P ((void));
 547
 548
 549 /* Return the maximum number of file descriptors
 550    the current process could possibly have.  */
 551 extern int __getdtablesize __P ((void));
 552 extern int getdtablesize __P ((void));
 553
 554
 555 /* Truncate FILE to LENGTH bytes.  */
 556 extern int truncate __P ((__const char *__file, __off_t __length));
 557
 558 /* Truncate the file FD is open on to LENGTH bytes.  */
 559 extern int ftruncate __P ((int __fd, __off_t __length));
 560
 561
 562 /* Make all changes done to FD actually appear on disk.  */
 563 extern int fsync __P ((int __fd));
 564
 565 /* Make all changes done to all files actually appear on disk.  */
 566 extern int sync __P ((void));
 567
 568
 569 /* Revoke access permissions to all processes currently communicating
 570    with the control terminal, and then send a SIGHUP signal to the process
 571    group of the control terminal.  */
 572 extern int vhangup __P ((void));
 573
 574 /* Revoke the access of all descriptors currently open on FILE.  */
 575 extern int revoke __P ((const char *__file));
 576
 577
 578 /* Enable statistical profiling, writing samples of the PC into at most
 579    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 580    is enabled, the system examines the user PC and increments
 581    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 582    disable profiling.  Returns zero on success, -1 on error.  */
 583 extern int profil __P ((unsigned short int *__sample_buffer, size_t __size,
 584                         size_t __offset, unsigned int __scale));
 585
 586
 587 /* Turn accounting on if NAME is an existing file.  The system will then write
 588    a record for each process as it terminates, to this file.  If NAME is NULL,
 589    turn accounting off.  This call is restricted to the super-user.  */
 590 extern int acct __P ((__const char *__name));
 591
 592 /* Make PATH be the root directory (the starting point for absolute paths).
 593    This call is restricted to the super-user.  */
 594 extern int chroot __P ((__const char *__path));
 595
 596 /* Make the block special device PATH available to the system for swapping.
 597    This call is restricted to the super-user.  */
 598 extern int swapon __P ((__const char *__path));
 599
 600 /* Reboot or halt the system.  */
 601 extern int reboot __P ((int __howto));
 602
 603
 604 /* Successive calls return the shells listed in `/etc/shells'.  */
 605 extern char *getusershell __P ((void));
 606 extern void endusershell __P ((void)); /* Discard cached info.  */
 607 extern void setusershell __P ((void)); /* Rewind and re-read the file.  */
 608
 609
 610 /* Prompt with PROMPT and read a string from the terminal without echoing.
 611    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 612 extern char *getpass __P ((const char *__prompt));
 613
 614 /* Put the program in the background, and dissociate from the controlling
 615    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 616    redirects stdin, stdout, and stderr to /dev/null.  */
 617 extern int daemon __P ((int __nochdir, int __noclose));
 618
 619 #endif /* Use BSD.  */
 620
 621
 622 #ifdef __USE_MISC
 623
 624 /* Generate a unique temporary file name from TEMPLATE.
 625    The last six characters of TEMPLATE must be "XXXXXX";
 626    they are replaced with a string that makes the file name unique.
 627    Returns TEMPLATE, or a null pointer if it cannot get a unique file name.  */
 628 extern char *mktemp __P ((char *__template));
 629
 630 /* Generate a unique temporary file name from TEMPLATE.
 631    The last six characters of TEMPLATE must be "XXXXXX";
 632    they are replaced with a string that makes the filename unique.
 633    Returns a file descriptor open on the file for reading and writing,
 634    or -1 if it cannot create a uniquely-named file.  */
 635 extern int mkstemp __P ((char *__template));
 636
 637
 638 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 639    This is completely system-dependent, and not often useful.
 640
 641    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 642    for errors; in many systems you cannot pass arguments or get return
 643    values for all system calls (`pipe', `fork', and `getppid' typically
 644    among them).
 645
 646    In Mach, all system calls take normal arguments and always return an
 647    error code (zero for success).  */
 648 extern int syscall __P ((int __sysno, ...));
 649
 650 #endif  /* Use misc.  */
 651
 652
 653 #if defined (__USE_MISC) && !defined (F_LOCK)
 654 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
 655    files consistent.  Some systems have them there and some here, and some
 656    software depends on the macros being defined without including both.  */
 657
 658 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 659    LEN is always relative to the current file position.
 660    The CMD argument is one of the following.  */
 661
 662 #define F_ULOCK 0       /* Unlock a previously locked region.  */
 663 #define F_LOCK  1       /* Lock a region for exclusive use.  */
 664 #define F_TLOCK 2       /* Test and lock a region for exclusive use.  */
 665 #define F_TEST  3       /* Test a region for other processes locks.  */
 666
 667 extern int lockf __P ((int __fd, int __cmd, __off_t __len));
 668 #endif /* Use misc and F_LOCK not already defined.  */
 669
 670
 671 #ifdef __USE_GNU
 672
 673 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
 674    set to EINTR.  */
 675
 676 #define TEMP_FAILURE_RETRY(expression) \
 677   ({ long int __result;                                                       \
 678        do __result = (long int) (expression);                                 \
 679        while (__result == -1L && errno == EINTR);                             \
 680        __result; })
 681
 682 #endif
 683
 684 __END_DECLS
 685
 686 #endif /* unistd.h  */