posix/unistd.h

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96, 97 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 not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, 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 and
  34    extended by P1003.1b (aka POSIX.4).  */
  35 #define _POSIX_VERSION  199309L
  36
  37 /* These are not #ifdef __USE_POSIX2 because they are
  38    in the theoretically application-owned namespace.  */
  39
  40 #define _POSIX2_C_VERSION       199912L /* Invalid until 1003.2 is done.  */
  41
  42 /* If defined, the implementation supports the
  43    C Language Bindings Option.  */
  44 #define _POSIX2_C_BIND  1
  45
  46 /* If defined, the implementation supports the
  47    C Language Development Utilities Option.  */
  48 #define _POSIX2_C_DEV   1
  49
  50 /* If defined, the implementation supports the
  51    Software Development Utilities Option.  */
  52 #define _POSIX2_SW_DEV  1
  53
  54 /* If defined, the implementation supports the
  55    creation of locales with the localedef utility.  */
  56 #define _POSIX2_LOCALEDEF       1
  57
  58 /* Library conforms to X/Open version 4.  */
  59 #define _XOPEN_VERSION  4
  60
  61 /* Commands and utilities from XPG4 are available.  */
  62 #define _XOPEN_XCU_VERSION      4
  63
  64 /* We are compatible with the old published standards as well.  */
  65 #define _XOPEN_XPG2     1
  66 #define _XOPEN_XPG3     1
  67 #define _XOPEN_XPG4     1
  68
  69 /* The X/Open Unix extensions are available.  */
  70 #define _XOPEN_UNIX     1
  71
  72 /* Encryption is present.  */
  73 #define _XOPEN_CRYPT    1
  74
  75 /* The enhanced internationalization capabilities according to XPG4.2
  76    are present.  */
  77 #define _XOPEN_ENH_I18N 1
  78
  79
  80 /* Get values of POSIX options:
  81
  82    If these symbols are defined, the corresponding features are
  83    always available.  If not, they may be available sometimes.
  84    The current values can be obtained with `sysconf'.
  85
  86    _POSIX_JOB_CONTROL           Job control is supported.
  87    _POSIX_SAVED_IDS             Processes have a saved set-user-ID
  88                                 and a saved set-group-ID.
  89    _POSIX_REALTIME_SIGNALS      Real-time, queued signals are supported.
  90    _POSIX_PRIORITY_SCHEDULING   Priority scheduling is supported.
  91    _POSIX_TIMERS                POSIX.4 clocks and timers are supported.
  92    _POSIX_ASYNCHRONOUS_IO       Asynchronous I/O is supported.
  93    _POSIX_PRIORITIZED_IO        Prioritized asynchronous I/O is supported.
  94    _POSIX_SYNCHRONIZED_IO       Synchronizing file data is supported.
  95    _POSIX_FSYNC                 The fsync function is present.
  96    _POSIX_MAPPED_FILES          Mapping of files to memory is supported.
  97    _POSIX_MEMLOCK               Locking of all memory is supported.
  98    _POSIX_MEMLOCK_RANGE         Locking of ranges of memory is supported.
  99    _POSIX_MEMORY_PROTECTION     Setting of memory protections is supported.
 100    _POSIX_MESSAGE_PASSING       POSIX.4 message queues are supported.
 101    _POSIX_SEMAPHORES            POSIX.4 counting semaphores are supported.
 102    _POSIX_SHARED_MEMORY_OBJECTS POSIX.4 shared memory objects are supported.
 103    _POSIX_PII                   Protocol-independent interfaces are supported.
 104    _POSIX_PII_XTI               XTI protocol-indep. interfaces are supported.
 105    _POSIX_PII_SOCKET            Socket protocol-indep. interfaces are supported.
 106    _POSIX_PII_INTERNET          Internet family of protocols supported.
 107    _POSIX_PII_INTERNET_STREAM   Connection-mode Internet protocol supported.
 108    _POSIX_PII_INTERNET_DGRAM    Connectionless Internet protocol supported.
 109    _POSIX_PII_OSI               ISO/OSI family of protocols supported.
 110    _POSIX_PII_OSI_COTS          Connection-mode ISO/OSI service supported.
 111    _POSIX_PII_OSI_CLTS          Connectionless ISO/OSI service supported.
 112    _POSIX_POLL                  Implementation supports `poll' function.
 113    _POSIX_SELECT                Implementation supports `select' and `pselect'.
 114
 115    _XOPEN_SHM                   Shared memory interface according to XPG4.2.
 116
 117    If any of these symbols is defined as -1, the corresponding option is not
 118    true for any file.  If any is defined as other than -1, the corresponding
 119    option is true for all files.  If a symbol is not defined at all, the value
 120    for a specific file can be obtained from `pathconf' and `fpathconf'.
 121
 122    _POSIX_CHOWN_RESTRICTED      Only the super user can use `chown' to change
 123                                 the owner of a file.  `chown' can only be used
 124                                 to change the group ID of a file to a group of
 125                                 which the calling process is a member.
 126    _POSIX_NO_TRUNC              Pathname components longer than
 127                                 NAME_MAX generate an error.
 128    _POSIX_VDISABLE              If defined, if the value of an element of the
 129                                 `c_cc' member of `struct termios' is
 130                                 _POSIX_VDISABLE, no character will have the
 131                                 effect associated with that element.
 132    _POSIX_SYNC_IO               Synchronous I/O may be performed.
 133    _POSIX_ASYNC_IO              Asynchronous I/O may be performed.
 134    _POSIX_PRIO_IO               Prioritized Asynchronous I/O may be performed.
 135    */
 136
 137 #include <posix_opt.h>
 138
 139
 140 /* Standard file descriptors.  */
 141 #define STDIN_FILENO    0       /* Standard input.  */
 142 #define STDOUT_FILENO   1       /* Standard output.  */
 143 #define STDERR_FILENO   2       /* Standard error output.  */
 144
 145
 146 /* All functions that are not declared anywhere else.  */
 147
 148 #include <gnu/types.h>
 149
 150 #ifndef ssize_t
 151 typedef __ssize_t ssize_t;
 152 #define ssize_t ssize_t
 153 #endif
 154
 155 #define __need_size_t
 156 #define __need_NULL
 157 #include <stddef.h>
 158
 159
 160 /* Values for the second argument to access.
 161    These may be OR'd together.  */
 162 #define R_OK    4               /* Test for read permission.  */
 163 #define W_OK    2               /* Test for write permission.  */
 164 #define X_OK    1               /* Test for execute permission.  */
 165 #define F_OK    0               /* Test for existence.  */
 166
 167 /* Test for access to NAME using the real UID and real GID.  */
 168 extern int __access __P ((__const char *__name, int __type));
 169 extern int access __P ((__const char *__name, int __type));
 170
 171 #ifdef __USE_GNU
 172 /* Test for access to NAME using the effective UID and GID
 173    (as normal file operations use).  */
 174 extern int euidaccess __P ((__const char *__name, int __type));
 175 #endif
 176
 177
 178 /* Values for the WHENCE argument to lseek.  */
 179 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 180 #define SEEK_SET        0       /* Seek from beginning of file.  */
 181 #define SEEK_CUR        1       /* Seek from current position.  */
 182 #define SEEK_END        2       /* Seek from end of file.  */
 183 #endif
 184
 185 #if defined (__USE_BSD) && !defined (L_SET)
 186 /* Old BSD names for the same constants; just for compatibility.  */
 187 #define L_SET           SEEK_SET
 188 #define L_INCR          SEEK_CUR
 189 #define L_XTND          SEEK_END
 190 #endif
 191
 192
 193 /* Move FD's file position to OFFSET bytes from the
 194    beginning of the file (if WHENCE is SEEK_SET),
 195    the current position (if WHENCE is SEEK_CUR),
 196    or the end of the file (if WHENCE is SEEK_END).
 197    Return the new file position.  */
 198 extern __off_t __lseek __P ((int __fd, __off_t __offset, int __whence));
 199 extern __off_t lseek __P ((int __fd, __off_t __offset, int __whence));
 200
 201 /* Close the file descriptor FD.  */
 202 extern int __close __P ((int __fd));
 203 extern int close __P ((int __fd));
 204
 205 /* Read NBYTES into BUF from FD.  Return the
 206    number read, -1 for errors or 0 for EOF.  */
 207 extern ssize_t __read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 208 extern ssize_t read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 209
 210 /* Write N bytes of BUF to FD.  Return the number written, or -1.  */
 211 extern ssize_t __write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 212 extern ssize_t write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 213
 214
 215 /* Create a one-way communication channel (pipe).
 216    If successful, two file descriptors are stored in PIPEDES;
 217    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 218    Returns 0 if successful, -1 if not.  */
 219 extern int __pipe __P ((int __pipedes[2]));
 220 extern int pipe __P ((int __pipedes[2]));
 221
 222 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 223    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 224    The function returns the number of seconds remaining until the last
 225    alarm scheduled would have signaled, or zero if there wasn't one.
 226    There is no return value to indicate an error, but you can set `errno'
 227    to 0 and check its value after calling `alarm', and this might tell you.
 228    The signal may come late due to processor scheduling.  */
 229 extern unsigned int alarm __P ((unsigned int __seconds));
 230
 231 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 232    and is not ignored.  The function returns the number of seconds less
 233    than SECONDS which it actually slept (thus zero if it slept the full time).
 234    If a signal handler does a `longjmp' or modifies the handling of the
 235    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 236    signal afterwards is undefined.  There is no return value to indicate
 237    error, but if `sleep' returns SECONDS, it probably didn't work.  */
 238 extern unsigned int __sleep __P ((unsigned int __seconds));
 239 extern unsigned int sleep __P ((unsigned int __seconds));
 240
 241 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 242 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 243    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 244    timer is reset to go off every INTERVAL microseconds thereafter.
 245    Returns the number of microseconds remaining before the alarm.  */
 246 extern unsigned int ualarm __P ((unsigned int __value,
 247                                  unsigned int __interval));
 248
 249 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 250    or ignored.  */
 251 extern void usleep __P ((unsigned int __useconds));
 252 #endif
 253
 254
 255 /* Suspend the process until a signal arrives.
 256    This always returns -1 and sets `errno' to EINTR.  */
 257 extern int pause __P ((void));
 258
 259
 260 /* Change the owner and group of FILE.  */
 261 extern int __chown __P ((__const char *__file,
 262                          __uid_t __owner, __gid_t __group));
 263 extern int chown __P ((__const char *__file,
 264                        __uid_t __owner, __gid_t __group));
 265
 266 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 267 /* Change the owner and group of the file that FD is open on.  */
 268 extern int __fchown __P ((int __fd,
 269                           __uid_t __owner, __gid_t __group));
 270 extern int fchown __P ((int __fd,
 271                         __uid_t __owner, __gid_t __group));
 272
 273
 274 /* Change owner and group of FILE, if it is a symbolic
 275    link the ownership of the symbolic link is changed.  */
 276 extern int __lchown __P ((__const char *__file, __uid_t __owner,
 277                           __gid_t __group));
 278 extern int lchown __P ((__const char *__file, __uid_t __owner,
 279                         __gid_t __group));
 280
 281 #endif /* Use BSD || X/Open Unix.  */
 282
 283 /* Change the process's working directory to PATH.  */
 284 extern int __chdir __P ((__const char *__path));
 285 extern int chdir __P ((__const char *__path));
 286
 287 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 288 /* Change the process's working directory to the one FD is open on.  */
 289 extern int fchdir __P ((int __fd));
 290 #endif
 291
 292 /* Get the pathname of the current working directory,
 293    and put it in SIZE bytes of BUF.  Returns NULL if the
 294    directory couldn't be determined or SIZE was too small.
 295    If successful, returns BUF.  In GNU, if BUF is NULL,
 296    an array is allocated with `malloc'; the array is SIZE
 297    bytes long, unless SIZE <= 0, in which case it is as
 298    big as necessary.  */
 299 extern char *__getcwd __P ((char *__buf, size_t __size));
 300 extern char *getcwd __P ((char *__buf, size_t __size));
 301
 302 #ifdef  __USE_GNU
 303 /* Return a malloc'd string containing the current directory name.
 304    If the environment variable `PWD' is set, and its value is correct,
 305    that value is used.  */
 306 extern char *get_current_dir_name __P ((void));
 307
 308 /* Get the canonical absolute name of the named directory, and put it in SIZE
 309    bytes of BUF.  Returns NULL if the directory couldn't be determined or
 310    SIZE was too small.  If successful, returns BUF.  In GNU, if BUF is
 311    NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
 312    unless SIZE <= 0, in which case it is as big as necessary.  */
 313
 314 char *__canonicalize_directory_name_internal __P ((__const char *__thisdir,
 315                                                    char *__buf,
 316                                                    size_t __size));
 317 #endif
 318
 319 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 320 /* Put the absolute pathname of the current working directory in BUF.
 321    If successful, return BUF.  If not, put an error message in
 322    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 323 extern char *getwd __P ((char *__buf));
 324 #endif
 325
 326
 327 /* Duplicate FD, returning a new file descriptor on the same file.  */
 328 extern int __dup __P ((int __fd));
 329 extern int dup __P ((int __fd));
 330
 331 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 332 extern int __dup2 __P ((int __fd, int __fd2));
 333 extern int dup2 __P ((int __fd, int __fd2));
 334
 335 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 336 extern char **__environ;
 337 #ifdef __USE_GNU
 338 extern char **environ;
 339 #endif
 340
 341
 342 /* Replace the current process, executing PATH with arguments ARGV and
 343    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 344 extern int __execve __P ((__const char *__path, char *__const __argv[],
 345                           char *__const __envp[]));
 346 extern int execve __P ((__const char *__path, char *__const __argv[],
 347                         char *__const __envp[]));
 348
 349 #ifdef __USE_GNU
 350 /* Execute the file FD refers to, overlaying the running program image.
 351    ARGV and ENVP are passed to the new program, as for `execve'.  */
 352 extern int fexecve __P ((int __fd,
 353                          char *__const __argv[], char *__const __envp[]));
 354
 355 #endif
 356
 357
 358 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 359 extern int execv __P ((__const char *__path, char *__const __argv[]));
 360
 361 /* Execute PATH with all arguments after PATH until a NULL pointer,
 362    and the argument after that for environment.  */
 363 extern int execle __P ((__const char *__path, __const char *__arg, ...));
 364
 365 /* Execute PATH with all arguments after PATH until
 366    a NULL pointer and environment from `environ'.  */
 367 extern int execl __P ((__const char *__path, __const char *__arg, ...));
 368
 369 /* Execute FILE, searching in the `PATH' environment variable if it contains
 370    no slashes, with arguments ARGV and environment from `environ'.  */
 371 extern int execvp __P ((__const char *__file, char *__const __argv[]));
 372
 373 /* Execute FILE, searching in the `PATH' environment variable if
 374    it contains no slashes, with all arguments after FILE until a
 375    NULL pointer and environment from `environ'.  */
 376 extern int execlp __P ((__const char *__file, __const char *__arg, ...));
 377
 378
 379 #if defined(__USE_MISC) || defined(__USE_XOPEN)
 380 /* Add INC to priority of the current process.  */
 381 extern int nice __P ((int __inc));
 382 #endif
 383
 384
 385 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 386 extern void _exit __P ((int __status)) __attribute__ ((__noreturn__));
 387
 388
 389 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 390    the `_SC_*' symbols for the NAME argument to `sysconf';
 391    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 392 #include <confname.h>
 393
 394 /* Get file-specific configuration information about PATH.  */
 395 extern long int __pathconf __P ((__const char *__path, int __name));
 396 extern long int pathconf __P ((__const char *__path, int __name));
 397
 398 /* Get file-specific configuration about descriptor FD.  */
 399 extern long int __fpathconf __P ((int __fd, int __name));
 400 extern long int fpathconf __P ((int __fd, int __name));
 401
 402 /* Get the value of the system variable NAME.  */
 403 extern long int __sysconf __P ((int __name));
 404 extern long int sysconf __P ((int __name));
 405
 406 #ifdef  __USE_POSIX2
 407 /* Get the value of the string-valued system variable NAME.  */
 408 extern size_t confstr __P ((int __name, char *__buf, size_t __len));
 409 #endif
 410
 411
 412 /* Get the process ID of the calling process.  */
 413 extern __pid_t __getpid __P ((void));
 414 extern __pid_t getpid __P ((void));
 415
 416 /* Get the process ID of the calling process's parent.  */
 417 extern __pid_t __getppid __P ((void));
 418 extern __pid_t getppid __P ((void));
 419
 420 /* Get the process group ID of the calling process.  */
 421 extern __pid_t getpgrp __P ((void));
 422
 423 /* Set the process group ID of the process matching PID to PGID.
 424    If PID is zero, the current process's process group ID is set.
 425    If PGID is zero, the process ID of the process is used.  */
 426 extern int setpgid __P ((__pid_t __pid, __pid_t __pgid));
 427
 428 /* Get the process group ID of process PID.  */
 429 extern __pid_t __getpgid __P ((__pid_t __pid));
 430 #ifdef __USE_XOPEN_EXTENDED
 431 extern __pid_t getpgid __P ((__pid_t __pid));
 432 #endif
 433
 434 #if defined(__USE_SVID) || defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 435 /* Both System V and BSD have `setpgrp' functions, but with different
 436    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 437    (above).  The System V function takes no arguments and puts the calling
 438    process in its on group like `setpgid (0, 0)'.
 439
 440    New programs should always use `setpgid' instead.
 441
 442    The default in GNU is to provide the System V function.  The BSD
 443    function is available under -D_BSD_SOURCE with -lbsd-compat.  */
 444
 445 #ifndef __FAVOR_BSD
 446
 447 /* Set the process group ID of the calling process to its own PID.
 448    This is exactly the same as `setpgid (0, 0)'.  */
 449 extern int setpgrp __P ((void));
 450
 451 #else
 452
 453 /* Another name for `setpgid' (above).  */
 454 extern int setpgrp __P ((__pid_t __pid, __pid_t __pgrp));
 455
 456 #endif  /* Favor BSD.  */
 457 #endif  /* Use SVID or BSD.  */
 458
 459 /* Create a new session with the calling process as its leader.
 460    The process group IDs of the session and the calling process
 461    are set to the process ID of the calling process, which is returned.  */
 462 extern __pid_t __setsid __P ((void));
 463 extern __pid_t setsid __P ((void));
 464
 465 #ifdef __USE_XOPEN_EXTENDED
 466 /* Return the session ID of the given process.  */
 467 extern __pid_t getsid __P ((__pid_t __pid));
 468 #endif
 469
 470 /* Get the real user ID of the calling process.  */
 471 extern __uid_t __getuid __P ((void));
 472 extern __uid_t getuid __P ((void));
 473
 474 /* Get the effective user ID of the calling process.  */
 475 extern __uid_t __geteuid __P ((void));
 476 extern __uid_t geteuid __P ((void));
 477
 478 /* Get the real group ID of the calling process.  */
 479 extern __gid_t __getgid __P ((void));
 480 extern __gid_t getgid __P ((void));
 481
 482 /* Get the effective group ID of the calling process.  */
 483 extern __gid_t __getegid __P ((void));
 484 extern __gid_t getegid __P ((void));
 485
 486 /* If SIZE is zero, return the number of supplementary groups
 487    the calling process is in.  Otherwise, fill in the group IDs
 488    of its supplementary groups in LIST and return the number written.  */
 489 extern int __getgroups __P ((int __size, __gid_t __list[]));
 490 extern int getgroups __P ((int __size, __gid_t __list[]));
 491
 492 #ifdef  __USE_GNU
 493 /* Return nonzero iff the calling process is in group GID.  */
 494 extern int __group_member __P ((__gid_t __gid));
 495 extern int group_member __P ((__gid_t __gid));
 496 #endif
 497
 498 /* Set the user ID of the calling process to UID.
 499    If the calling process is the super-user, set the real
 500    and effective user IDs, and the saved set-user-ID to UID;
 501    if not, the effective user ID is set to UID.  */
 502 extern int __setuid __P ((__uid_t __uid));
 503 extern int setuid __P ((__uid_t __uid));
 504
 505 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 506 /* Set the real user ID of the calling process to RUID,
 507    and the effective user ID of the calling process to EUID.  */
 508 extern int __setreuid __P ((__uid_t __ruid, __uid_t __euid));
 509 extern int setreuid __P ((__uid_t __ruid, __uid_t __euid));
 510 #endif
 511
 512 #ifdef  __USE_BSD
 513 /* Set the effective user ID of the calling process to UID.  */
 514 extern int seteuid __P ((__uid_t __uid));
 515 #endif /* Use BSD.  */
 516
 517 /* Set the group ID of the calling process to GID.
 518    If the calling process is the super-user, set the real
 519    and effective group IDs, and the saved set-group-ID to GID;
 520    if not, the effective group ID is set to GID.  */
 521 extern int __setgid __P ((__gid_t __gid));
 522 extern int setgid __P ((__gid_t __gid));
 523
 524 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 525 /* Set the real group ID of the calling process to RGID,
 526    and the effective group ID of the calling process to EGID.  */
 527 extern int __setregid __P ((__gid_t __rgid, __gid_t __egid));
 528 extern int setregid __P ((__gid_t __rgid, __gid_t __egid));
 529 #endif
 530
 531 #ifdef __USE_BSD
 532 /* Set the effective group ID of the calling process to GID.  */
 533 extern int setegid __P ((__gid_t __gid));
 534 #endif /* Use BSD.  */
 535
 536
 537 /* Clone the calling process, creating an exact copy.
 538    Return -1 for errors, 0 to the new process,
 539    and the process ID of the new process to the old process.  */
 540 extern __pid_t __fork __P ((void));
 541 extern __pid_t fork __P ((void));
 542
 543 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 544 /* Clone the calling process, but without copying the whole address space.
 545    The the calling process is suspended until the the new process exits or is
 546    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 547    and the process ID of the new process to the old process.  */
 548 extern __pid_t __vfork __P ((void));
 549 extern __pid_t vfork __P ((void));
 550 #endif /* Use BSD. */
 551
 552
 553 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 554    The returned storage is good only until the next call to this function.  */
 555 extern char *ttyname __P ((int __fd));
 556
 557 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 558    open on in BUF.  Return 0 on success, -1 otherwise.  */
 559 extern int __ttyname_r __P ((int __fd, char *__buf, size_t __buflen));
 560 extern int ttyname_r __P ((int __fd, char *__buf, size_t __buflen));
 561
 562 /* Return 1 if FD is a valid descriptor associated
 563    with a terminal, zero if not.  */
 564 extern int __isatty __P ((int __fd));
 565 extern int isatty __P ((int __fd));
 566
 567 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 568 /* Return the index into the active-logins file (utmp) for
 569    the controlling terminal.  */
 570 extern int ttyslot __P ((void));
 571 #endif
 572
 573
 574 /* Make a link to FROM named TO.  */
 575 extern int __link __P ((__const char *__from, __const char *__to));
 576 extern int link __P ((__const char *__from, __const char *__to));
 577
 578 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 579 /* Make a symbolic link to FROM named TO.  */
 580 extern int __symlink __P ((__const char *__from, __const char *__to));
 581 extern int symlink __P ((__const char *__from, __const char *__to));
 582
 583 /* Read the contents of the symbolic link PATH into no more than
 584    LEN bytes of BUF.  The contents are not null-terminated.
 585    Returns the number of characters read, or -1 for errors.  */
 586 extern int __readlink __P ((__const char *__path, char *__buf, size_t __len));
 587 extern int readlink __P ((__const char *__path, char *__buf, size_t __len));
 588 #endif /* Use BSD.  */
 589
 590 /* Remove the link NAME.  */
 591 extern int __unlink __P ((__const char *__name));
 592 extern int unlink __P ((__const char *__name));
 593
 594 /* Remove the directory PATH.  */
 595 extern int __rmdir __P ((__const char *__path));
 596 extern int rmdir __P ((__const char *__path));
 597
 598
 599 /* Return the foreground process group ID of FD.  */
 600 extern __pid_t tcgetpgrp __P ((int __fd));
 601
 602 /* Set the foreground process group ID of FD set PGRP_ID.  */
 603 extern int tcsetpgrp __P ((int __fd, __pid_t __pgrp_id));
 604
 605
 606 /* Return the login name of the user.  */
 607 extern char *getlogin __P ((void));
 608 #ifdef __USE_REENTRANT
 609 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 610    If it cannot be determined or some other error occurred, return the error
 611    code.  Otherwise return 0.  */
 612 extern int getlogin_r __P ((char *__name, size_t __name_len));
 613 #endif
 614
 615 #ifdef  __USE_BSD
 616 /* Set the login name returned by `getlogin'.  */
 617 extern int setlogin __P ((__const char *__name));
 618 #endif
 619
 620
 621 #ifdef  __USE_POSIX2
 622 /* Process the arguments in ARGV (ARGC of them, minus
 623    the program name) for options given in OPTS.
 624
 625    If `opterr' is zero, no messages are generated
 626    for invalid options; it defaults to 1.
 627    `optind' is the current index into ARGV.
 628    `optarg' is the argument corresponding to the current option.
 629    Return the option character from OPTS just read.
 630    Return -1 when there are no more options.
 631    For unrecognized options, or options missing arguments,
 632    `optopt' is set to the option letter, and '?' is returned.
 633
 634    The OPTS string is a list of characters which are recognized option
 635    letters, optionally followed by colons, specifying that that letter
 636    takes an argument, to be placed in `optarg'.
 637
 638    If a letter in OPTS is followed by two colons, its argument is optional.
 639    This behavior is specific to the GNU `getopt'.
 640
 641    The argument `--' causes premature termination of argument scanning,
 642    explicitly telling `getopt' that there are no more options.
 643
 644    If OPTS begins with `--', then non-option arguments
 645    are treated as arguments to the option '\0'.
 646    This behavior is specific to the GNU `getopt'.  */
 647 extern int getopt __P ((int __argc, char *__const * __argv,
 648                         __const char *__opts));
 649 extern int opterr;
 650 extern int optind;
 651 extern int optopt;
 652 extern char *optarg;
 653 #endif
 654
 655
 656 #if defined(__USE_BSD) || defined (__USE_XOPEN)
 657
 658 /* Put the name of the current host in no more than LEN bytes of NAME.
 659    The result is null-terminated if LEN is large enough for the full
 660    name and the terminator.  */
 661 extern int __gethostname __P ((char *__name, size_t __len));
 662 extern int gethostname __P ((char *__name, size_t __len));
 663
 664 /* Set the name of the current host to NAME, which is LEN bytes long.
 665    This call is restricted to the super-user.  */
 666 extern int sethostname __P ((__const char *__name, size_t __len));
 667
 668 /* Set the current machine's Internet number to ID.
 669    This call is restricted to the super-user.  */
 670 extern int sethostid __P ((long int __id));
 671
 672
 673 /* Get and set the NIS (aka YP) domain name, if any.
 674    Called just like `gethostname' and `sethostname'.
 675    The NIS domain name is usually the empty string when not using NIS.  */
 676 extern int getdomainname __P ((char *__name, size_t __len));
 677 extern int setdomainname __P ((__const char *__name, size_t __len));
 678
 679
 680 /* Make all changes done to FD actually appear on disk.  */
 681 extern int fsync __P ((int __fd));
 682
 683
 684 /* Revoke access permissions to all processes currently communicating
 685    with the control terminal, and then send a SIGHUP signal to the process
 686    group of the control terminal.  */
 687 extern int vhangup __P ((void));
 688
 689 /* Revoke the access of all descriptors currently open on FILE.  */
 690 extern int revoke __P ((__const char *__file));
 691
 692
 693 /* Enable statistical profiling, writing samples of the PC into at most
 694    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 695    is enabled, the system examines the user PC and increments
 696    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 697    disable profiling.  Returns zero on success, -1 on error.  */
 698 extern int profil __P ((unsigned short int *__sample_buffer, size_t __size,
 699                         size_t __offset, unsigned int __scale));
 700
 701
 702 /* Turn accounting on if NAME is an existing file.  The system will then write
 703    a record for each process as it terminates, to this file.  If NAME is NULL,
 704    turn accounting off.  This call is restricted to the super-user.  */
 705 extern int acct __P ((__const char *__name));
 706
 707 /* Make PATH be the root directory (the starting point for absolute paths).
 708    This call is restricted to the super-user.  */
 709 extern int chroot __P ((__const char *__path));
 710
 711
 712 /* Successive calls return the shells listed in `/etc/shells'.  */
 713 extern char *getusershell __P ((void));
 714 extern void endusershell __P ((void)); /* Discard cached info.  */
 715 extern void setusershell __P ((void)); /* Rewind and re-read the file.  */
 716
 717
 718 /* Prompt with PROMPT and read a string from the terminal without echoing.
 719    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 720 extern char *getpass __P ((__const char *__prompt));
 721
 722 /* Put the program in the background, and dissociate from the controlling
 723    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 724    redirects stdin, stdout, and stderr to /dev/null.  */
 725 extern int daemon __P ((int __nochdir, int __noclose));
 726
 727 #endif /* Use BSD || X/Open.  */
 728
 729
 730 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 731
 732 /* Return the current machine's Internet number.  */
 733 extern long int gethostid __P ((void));
 734
 735 /* Make all changes done to all files actually appear on disk.  */
 736 extern int sync __P ((void));
 737
 738
 739 /* Return the number of bytes in a page.  This is the system's page size,
 740    which is not necessarily the same as the hardware page size.  */
 741 extern int __getpagesize __P ((void));
 742 extern int getpagesize __P ((void));
 743
 744
 745 /* Truncate FILE to LENGTH bytes.  */
 746 extern int truncate __P ((__const char *__file, __off_t __length));
 747
 748 /* Truncate the file FD is open on to LENGTH bytes.  */
 749 extern int ftruncate __P ((int __fd, __off_t __length));
 750
 751
 752 /* Return the maximum number of file descriptors
 753    the current process could possibly have.  */
 754 extern int __getdtablesize __P ((void));
 755 extern int getdtablesize __P ((void));
 756
 757 #endif /* Use BSD || X/Open Unix.  */
 758
 759
 760 #if defined(__USE_MISC) || defined(__USE_XOPEN_EXTENDED)
 761
 762 /* Set the end of accessible data space (aka "the break") to ADDR.
 763    Returns zero on success and -1 for errors (with errno set).  */
 764 extern int __brk __P ((__ptr_t __addr));
 765 extern int brk __P ((__ptr_t __addr));
 766
 767 #define __need_ptrdiff_t
 768 #include <stddef.h>
 769
 770 /* Increase or decrease the end of accessible data space by DELTA bytes.
 771    If successful, returns the address the previous end of data space
 772    (i.e. the beginning of the new space, if DELTA > 0);
 773    returns (void *) -1 for errors (with errno set).  */
 774 extern __ptr_t __sbrk __P ((ptrdiff_t __delta));
 775 extern __ptr_t sbrk __P ((ptrdiff_t __delta));
 776 #endif
 777
 778
 779 #ifdef __USE_MISC
 780 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 781    This is completely system-dependent, and not often useful.
 782
 783    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 784    for errors; in many systems you cannot pass arguments or get return
 785    values for all system calls (`pipe', `fork', and `getppid' typically
 786    among them).
 787
 788    In Mach, all system calls take normal arguments and always return an
 789    error code (zero for success).  */
 790 extern long int syscall __P ((long int __sysno, ...));
 791
 792 #endif  /* Use misc.  */
 793
 794
 795 #if (defined (__USE_MISC) || defined (__USE_XOPEN_EXTENDED)) \
 796     && !defined (F_LOCK)
 797 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
 798    files consistent.  Some systems have them there and some here, and some
 799    software depends on the macros being defined without including both.  */
 800
 801 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 802    LEN is always relative to the current file position.
 803    The CMD argument is one of the following.  */
 804
 805 #define F_ULOCK 0       /* Unlock a previously locked region.  */
 806 #define F_LOCK  1       /* Lock a region for exclusive use.  */
 807 #define F_TLOCK 2       /* Test and lock a region for exclusive use.  */
 808 #define F_TEST  3       /* Test a region for other processes locks.  */
 809
 810 extern int lockf __P ((int __fd, int __cmd, __off_t __len));
 811 #endif /* Use misc and F_LOCK not already defined.  */
 812
 813
 814 #ifdef __USE_GNU
 815
 816 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
 817    set to EINTR.  */
 818
 819 #define TEMP_FAILURE_RETRY(expression) \
 820   (__extension__                                                              \
 821     ({ long int __result;                                                     \
 822        do __result = (long int) (expression);                                 \
 823        while (__result == -1L && errno == EINTR);                             \
 824        __result; }))                                                          \
 825
 826
 827 /* This variable is set nonzero at startup if the process's effective IDs
 828    differ from its real IDs, or it is otherwise indicated that extra
 829    security should be used.  When this is set the dynamic linker ignores
 830    the various environment variables that normally affect it.  */
 831 extern int __libc_enable_secure;
 832
 833 #endif
 834
 835 #ifdef __USE_POSIX199309
 836 /* Synchronize at least the data part of a file with the underlying
 837    media.  */
 838 extern int fdatasync __P ((int __fildes));
 839 #endif /* Use POSIX199309 */
 840
 841
 842 /* XPG4.2 specifies that prototypes for the encryption functions must
 843    be defined here.  */
 844 #ifdef  __USE_XOPEN
 845 /* Encrypt at most 8 characters from KEY using salt to perturb DES.  */
 846 extern char *crypt __P ((__const char *__key, __const char *__salt));
 847
 848 /* Setup DES tables according KEY.  */
 849 extern void setkey __P ((__const char *__key));
 850
 851 /* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt
 852    block in place.  */
 853 extern void encrypt __P ((char *__block, int __edflag));
 854
 855
 856 /* Swab pairs bytes in the first N bytes of the area pointed to by
 857    FROM and copy the result to TO.  The value of TO must not be in the
 858    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
 859    is without partner.  */
 860 extern void swab __P ((__const char *__from, char *__to, ssize_t __n));
 861 #endif
 862
 863 __END_DECLS
 864
 865 #endif /* unistd.h  */