posix/unistd.h

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96 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
 240 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 241 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 242    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 243    timer is reset to go off every INTERVAL microseconds thereafter.
 244    Returns the number of microseconds remaining before the alarm.  */
 245 extern unsigned int ualarm __P ((unsigned int __value,
 246                                  unsigned int __interval));
 247
 248 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 249    or ignored.  */
 250 extern void usleep __P ((unsigned int __useconds));
 251 #endif
 252
 253
 254 /* Suspend the process until a signal arrives.
 255    This always returns -1 and sets `errno' to EINTR.  */
 256 extern int pause __P ((void));
 257
 258
 259 /* Change the owner and group of FILE.  */
 260 extern int __chown __P ((__const char *__file,
 261                          __uid_t __owner, __gid_t __group));
 262 extern int chown __P ((__const char *__file,
 263                        __uid_t __owner, __gid_t __group));
 264
 265 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 266 /* Change the owner and group of the file that FD is open on.  */
 267 extern int __fchown __P ((int __fd,
 268                           __uid_t __owner, __gid_t __group));
 269 extern int fchown __P ((int __fd,
 270                         __uid_t __owner, __gid_t __group));
 271
 272
 273 /* Change owner and group of FILE, if it is a symbolic
 274    link the ownership of the symbolic link is changed.  */
 275 extern int __lchown __P ((__const char *__file, __uid_t __owner,
 276                           __gid_t __group));
 277 extern int lchown __P ((__const char *__file, __uid_t __owner,
 278                         __gid_t __group));
 279
 280 #endif /* Use BSD || X/Open Unix.  */
 281
 282 /* Change the process's working directory to PATH.  */
 283 extern int __chdir __P ((__const char *__path));
 284 extern int chdir __P ((__const char *__path));
 285
 286 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 287 /* Change the process's working directory to the one FD is open on.  */
 288 extern int fchdir __P ((int __fd));
 289 #endif
 290
 291 /* Get the pathname of the current working directory,
 292    and put it in SIZE bytes of BUF.  Returns NULL if the
 293    directory couldn't be determined or SIZE was too small.
 294    If successful, returns BUF.  In GNU, if BUF is NULL,
 295    an array is allocated with `malloc'; the array is SIZE
 296    bytes long, unless SIZE <= 0, in which case it is as
 297    big as necessary.  */
 298 extern char *__getcwd __P ((char *__buf, size_t __size));
 299 extern char *getcwd __P ((char *__buf, size_t __size));
 300
 301 #ifdef  __USE_GNU
 302 /* Return a malloc'd string containing the current directory name.
 303    If the environment variable `PWD' is set, and its value is correct,
 304    that value is used.  */
 305 extern char *get_current_dir_name __P ((void));
 306
 307 /* Get the canonical absolute name of the named directory, and put it in SIZE
 308    bytes of BUF.  Returns NULL if the directory couldn't be determined or
 309    SIZE was too small.  If successful, returns BUF.  In GNU, if BUF is
 310    NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
 311    unless SIZE <= 0, in which case it is as big as necessary.  */
 312
 313 char *__canonicalize_directory_name_internal __P ((__const char *__thisdir,
 314                                                    char *__buf,
 315                                                    size_t __size));
 316 #endif
 317
 318 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 319 /* Put the absolute pathname of the current working directory in BUF.
 320    If successful, return BUF.  If not, put an error message in
 321    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 322 extern char *getwd __P ((char *__buf));
 323 #endif
 324
 325
 326 /* Duplicate FD, returning a new file descriptor on the same file.  */
 327 extern int __dup __P ((int __fd));
 328 extern int dup __P ((int __fd));
 329
 330 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 331 extern int __dup2 __P ((int __fd, int __fd2));
 332 extern int dup2 __P ((int __fd, int __fd2));
 333
 334 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 335 extern char **__environ;
 336
 337
 338 /* Replace the current process, executing PATH with arguments ARGV and
 339    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 340 extern int __execve __P ((__const char *__path, char *__const __argv[],
 341                           char *__const __envp[]));
 342 extern int execve __P ((__const char *__path, char *__const __argv[],
 343                         char *__const __envp[]));
 344
 345 #ifdef __USE_GNU
 346 /* Execute the file FD refers to, overlaying the running program image.
 347    ARGV and ENVP are passed to the new program, as for `execve'.  */
 348 extern int fexecve __P ((int __fd,
 349                          char *__const __argv[], char *__const __envp[]));
 350
 351 #endif
 352
 353
 354 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 355 extern int execv __P ((__const char *__path, char *__const __argv[]));
 356
 357 /* Execute PATH with all arguments after PATH until a NULL pointer,
 358    and the argument after that for environment.  */
 359 extern int execle __P ((__const char *__path, __const char *__arg, ...));
 360
 361 /* Execute PATH with all arguments after PATH until
 362    a NULL pointer and environment from `environ'.  */
 363 extern int execl __P ((__const char *__path, __const char *__arg, ...));
 364
 365 /* Execute FILE, searching in the `PATH' environment variable if it contains
 366    no slashes, with arguments ARGV and environment from `environ'.  */
 367 extern int execvp __P ((__const char *__file, char *__const __argv[]));
 368
 369 /* Execute FILE, searching in the `PATH' environment variable if
 370    it contains no slashes, with all arguments after FILE until a
 371    NULL pointer and environment from `environ'.  */
 372 extern int execlp __P ((__const char *__file, __const char *__arg, ...));
 373
 374
 375 #if defined(__USE_MISC) || defined(__USE_XOPEN)
 376 /* Add INC to priority of the current process.  */
 377 extern int nice __P ((int __inc));
 378 #endif
 379
 380
 381 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 382 extern void _exit __P ((int __status)) __attribute__ ((__noreturn__));
 383
 384
 385 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 386    the `_SC_*' symbols for the NAME argument to `sysconf';
 387    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 388 #include <confname.h>
 389
 390 /* Get file-specific configuration information about PATH.  */
 391 extern long int __pathconf __P ((__const char *__path, int __name));
 392 extern long int pathconf __P ((__const char *__path, int __name));
 393
 394 /* Get file-specific configuration about descriptor FD.  */
 395 extern long int __fpathconf __P ((int __fd, int __name));
 396 extern long int fpathconf __P ((int __fd, int __name));
 397
 398 /* Get the value of the system variable NAME.  */
 399 extern long int __sysconf __P ((int __name));
 400 extern long int sysconf __P ((int __name));
 401
 402 #ifdef  __USE_POSIX2
 403 /* Get the value of the string-valued system variable NAME.  */
 404 extern size_t confstr __P ((int __name, char *__buf, size_t __len));
 405 #endif
 406
 407
 408 /* Get the process ID of the calling process.  */
 409 extern __pid_t __getpid __P ((void));
 410 extern __pid_t getpid __P ((void));
 411
 412 /* Get the process ID of the calling process's parent.  */
 413 extern __pid_t __getppid __P ((void));
 414 extern __pid_t getppid __P ((void));
 415
 416 /* Get the process group ID of the calling process.  */
 417 extern __pid_t getpgrp __P ((void));
 418
 419 /* Set the process group ID of the process matching PID to PGID.
 420    If PID is zero, the current process's process group ID is set.
 421    If PGID is zero, the process ID of the process is used.  */
 422 extern int setpgid __P ((__pid_t __pid, __pid_t __pgid));
 423
 424 /* Get the process group ID of process PID.  */
 425 extern __pid_t __getpgid __P ((__pid_t __pid));
 426 #ifdef __USE_XOPEN_EXTENDED
 427 extern __pid_t getpgid __P ((__pid_t __pid));
 428 #endif
 429
 430 #if defined(__USE_SVID) || defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 431 /* Both System V and BSD have `setpgrp' functions, but with different
 432    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 433    (above).  The System V function takes no arguments and puts the calling
 434    process in its on group like `setpgid (0, 0)'.
 435
 436    New programs should always use `setpgid' instead.
 437
 438    The default in GNU is to provide the System V function.  The BSD
 439    function is available under -D_BSD_SOURCE with -lbsd-compat.  */
 440
 441 #ifndef __FAVOR_BSD
 442
 443 /* Set the process group ID of the calling process to its own PID.
 444    This is exactly the same as `setpgid (0, 0)'.  */
 445 extern int setpgrp __P ((void));
 446
 447 #else
 448
 449 /* Another name for `setpgid' (above).  */
 450 extern int setpgrp __P ((__pid_t __pid, __pid_t __pgrp));
 451
 452 #endif  /* Favor BSD.  */
 453 #endif  /* Use SVID or BSD.  */
 454
 455 /* Create a new session with the calling process as its leader.
 456    The process group IDs of the session and the calling process
 457    are set to the process ID of the calling process, which is returned.  */
 458 extern __pid_t __setsid __P ((void));
 459 extern __pid_t setsid __P ((void));
 460
 461 #ifdef __USE_XOPEN_EXTENDED
 462 /* Return the session ID of the given process.  */
 463 extern __pid_t getsid __P ((__pid_t __pid));
 464 #endif
 465
 466 /* Get the real user ID of the calling process.  */
 467 extern __uid_t __getuid __P ((void));
 468 extern __uid_t getuid __P ((void));
 469
 470 /* Get the effective user ID of the calling process.  */
 471 extern __uid_t __geteuid __P ((void));
 472 extern __uid_t geteuid __P ((void));
 473
 474 /* Get the real group ID of the calling process.  */
 475 extern __gid_t __getgid __P ((void));
 476 extern __gid_t getgid __P ((void));
 477
 478 /* Get the effective group ID of the calling process.  */
 479 extern __gid_t __getegid __P ((void));
 480 extern __gid_t getegid __P ((void));
 481
 482 /* If SIZE is zero, return the number of supplementary groups
 483    the calling process is in.  Otherwise, fill in the group IDs
 484    of its supplementary groups in LIST and return the number written.  */
 485 extern int __getgroups __P ((int __size, __gid_t __list[]));
 486 extern int getgroups __P ((int __size, __gid_t __list[]));
 487
 488 #ifdef  __USE_GNU
 489 /* Return nonzero iff the calling process is in group GID.  */
 490 extern int __group_member __P ((__gid_t __gid));
 491 extern int group_member __P ((__gid_t __gid));
 492 #endif
 493
 494 /* Set the user ID of the calling process to UID.
 495    If the calling process is the super-user, set the real
 496    and effective user IDs, and the saved set-user-ID to UID;
 497    if not, the effective user ID is set to UID.  */
 498 extern int __setuid __P ((__uid_t __uid));
 499 extern int setuid __P ((__uid_t __uid));
 500
 501 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 502 /* Set the real user ID of the calling process to RUID,
 503    and the effective user ID of the calling process to EUID.  */
 504 extern int __setreuid __P ((__uid_t __ruid, __uid_t __euid));
 505 extern int setreuid __P ((__uid_t __ruid, __uid_t __euid));
 506 #endif
 507
 508 #ifdef  __USE_BSD
 509 /* Set the effective user ID of the calling process to UID.  */
 510 extern int seteuid __P ((__uid_t __uid));
 511 #endif /* Use BSD.  */
 512
 513 /* Set the group ID of the calling process to GID.
 514    If the calling process is the super-user, set the real
 515    and effective group IDs, and the saved set-group-ID to GID;
 516    if not, the effective group ID is set to GID.  */
 517 extern int __setgid __P ((__gid_t __gid));
 518 extern int setgid __P ((__gid_t __gid));
 519
 520 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 521 /* Set the real group ID of the calling process to RGID,
 522    and the effective group ID of the calling process to EGID.  */
 523 extern int __setregid __P ((__gid_t __rgid, __gid_t __egid));
 524 extern int setregid __P ((__gid_t __rgid, __gid_t __egid));
 525 #endif
 526
 527 #ifdef __USE_BSD
 528 /* Set the effective group ID of the calling process to GID.  */
 529 extern int setegid __P ((__gid_t __gid));
 530 #endif /* Use BSD.  */
 531
 532
 533 /* Clone the calling process, creating an exact copy.
 534    Return -1 for errors, 0 to the new process,
 535    and the process ID of the new process to the old process.  */
 536 extern __pid_t __fork __P ((void));
 537 extern __pid_t fork __P ((void));
 538
 539 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 540 /* Clone the calling process, but without copying the whole address space.
 541    The the calling process is suspended until the the new process exits or is
 542    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 543    and the process ID of the new process to the old process.  */
 544 extern __pid_t __vfork __P ((void));
 545 extern __pid_t vfork __P ((void));
 546 #endif /* Use BSD. */
 547
 548
 549 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 550    The returned storage is good only until the next call to this function.  */
 551 extern char *ttyname __P ((int __fd));
 552 #ifdef __USE_REENTRANT
 553 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 554    open on in BUF.  Return 0 on success, -1 otherwise.  */
 555 extern int __ttyname_r __P ((int __fd, char *__buf, size_t __buflen));
 556 extern int ttyname_r __P ((int __fd, char *__buf, size_t __buflen));
 557 #endif
 558
 559 /* Return 1 if FD is a valid descriptor associated
 560    with a terminal, zero if not.  */
 561 extern int __isatty __P ((int __fd));
 562 extern int isatty __P ((int __fd));
 563
 564 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 565 /* Return the index into the active-logins file (utmp) for
 566    the controlling terminal.  */
 567 extern int ttyslot __P ((void));
 568 #endif
 569
 570
 571 /* Make a link to FROM named TO.  */
 572 extern int __link __P ((__const char *__from, __const char *__to));
 573 extern int link __P ((__const char *__from, __const char *__to));
 574
 575 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 576 /* Make a symbolic link to FROM named TO.  */
 577 extern int __symlink __P ((__const char *__from, __const char *__to));
 578 extern int symlink __P ((__const char *__from, __const char *__to));
 579
 580 /* Read the contents of the symbolic link PATH into no more than
 581    LEN bytes of BUF.  The contents are not null-terminated.
 582    Returns the number of characters read, or -1 for errors.  */
 583 extern int __readlink __P ((__const char *__path, char *__buf, size_t __len));
 584 extern int readlink __P ((__const char *__path, char *__buf, size_t __len));
 585 #endif /* Use BSD.  */
 586
 587 /* Remove the link NAME.  */
 588 extern int __unlink __P ((__const char *__name));
 589 extern int unlink __P ((__const char *__name));
 590
 591 /* Remove the directory PATH.  */
 592 extern int __rmdir __P ((__const char *__path));
 593 extern int rmdir __P ((__const char *__path));
 594
 595
 596 /* Return the foreground process group ID of FD.  */
 597 extern __pid_t tcgetpgrp __P ((int __fd));
 598
 599 /* Set the foreground process group ID of FD set PGRP_ID.  */
 600 extern int tcsetpgrp __P ((int __fd, __pid_t __pgrp_id));
 601
 602
 603 /* Return the login name of the user.  */
 604 extern char *getlogin __P ((void));
 605 #ifdef __USE_REENTRANT
 606 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 607    If it cannot be determined or some other error occurred, return the error
 608    code.  Otherwise return 0.  */
 609 extern int getlogin_r __P ((char *__name, size_t __name_len));
 610 #endif
 611
 612 #ifdef  __USE_BSD
 613 /* Set the login name returned by `getlogin'.  */
 614 extern int setlogin __P ((__const char *__name));
 615 #endif
 616
 617
 618 #ifdef  __USE_POSIX2
 619 /* Process the arguments in ARGV (ARGC of them, minus
 620    the program name) for options given in OPTS.
 621
 622    If `opterr' is zero, no messages are generated
 623    for invalid options; it defaults to 1.
 624    `optind' is the current index into ARGV.
 625    `optarg' is the argument corresponding to the current option.
 626    Return the option character from OPTS just read.
 627    Return -1 when there are no more options.
 628    For unrecognized options, or options missing arguments,
 629    `optopt' is set to the option letter, and '?' is returned.
 630
 631    The OPTS string is a list of characters which are recognized option
 632    letters, optionally followed by colons, specifying that that letter
 633    takes an argument, to be placed in `optarg'.
 634
 635    If a letter in OPTS is followed by two colons, its argument is optional.
 636    This behavior is specific to the GNU `getopt'.
 637
 638    The argument `--' causes premature termination of argument scanning,
 639    explicitly telling `getopt' that there are no more options.
 640
 641    If OPTS begins with `--', then non-option arguments
 642    are treated as arguments to the option '\0'.
 643    This behavior is specific to the GNU `getopt'.  */
 644 extern int getopt __P ((int __argc, char *__const * __argv,
 645                         __const char *__opts));
 646 extern int opterr;
 647 extern int optind;
 648 extern int optopt;
 649 extern char *optarg;
 650 #endif
 651
 652
 653 #if defined(__USE_BSD) || defined (__USE_XOPEN)
 654
 655 /* Put the name of the current host in no more than LEN bytes of NAME.
 656    The result is null-terminated if LEN is large enough for the full
 657    name and the terminator.  */
 658 extern int __gethostname __P ((char *__name, size_t __len));
 659 extern int gethostname __P ((char *__name, size_t __len));
 660
 661 /* Set the name of the current host to NAME, which is LEN bytes long.
 662    This call is restricted to the super-user.  */
 663 extern int sethostname __P ((__const char *__name, size_t __len));
 664
 665 /* Set the current machine's Internet number to ID.
 666    This call is restricted to the super-user.  */
 667 extern int sethostid __P ((long int __id));
 668
 669
 670 /* Get and set the NIS (aka YP) domain name, if any.
 671    Called just like `gethostname' and `sethostname'.
 672    The NIS domain name is usually the empty string when not using NIS.  */
 673 extern int getdomainname __P ((char *__name, size_t __len));
 674 extern int setdomainname __P ((__const char *__name, size_t __len));
 675
 676
 677 /* Make all changes done to FD actually appear on disk.  */
 678 extern int fsync __P ((int __fd));
 679
 680
 681 /* Revoke access permissions to all processes currently communicating
 682    with the control terminal, and then send a SIGHUP signal to the process
 683    group of the control terminal.  */
 684 extern int vhangup __P ((void));
 685
 686 /* Revoke the access of all descriptors currently open on FILE.  */
 687 extern int revoke __P ((__const char *__file));
 688
 689
 690 /* Enable statistical profiling, writing samples of the PC into at most
 691    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 692    is enabled, the system examines the user PC and increments
 693    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 694    disable profiling.  Returns zero on success, -1 on error.  */
 695 extern int profil __P ((unsigned short int *__sample_buffer, size_t __size,
 696                         size_t __offset, unsigned int __scale));
 697
 698
 699 /* Turn accounting on if NAME is an existing file.  The system will then write
 700    a record for each process as it terminates, to this file.  If NAME is NULL,
 701    turn accounting off.  This call is restricted to the super-user.  */
 702 extern int acct __P ((__const char *__name));
 703
 704 /* Make PATH be the root directory (the starting point for absolute paths).
 705    This call is restricted to the super-user.  */
 706 extern int chroot __P ((__const char *__path));
 707
 708
 709 /* Successive calls return the shells listed in `/etc/shells'.  */
 710 extern char *getusershell __P ((void));
 711 extern void endusershell __P ((void)); /* Discard cached info.  */
 712 extern void setusershell __P ((void)); /* Rewind and re-read the file.  */
 713
 714
 715 /* Prompt with PROMPT and read a string from the terminal without echoing.
 716    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 717 extern char *getpass __P ((__const char *__prompt));
 718
 719 /* Put the program in the background, and dissociate from the controlling
 720    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 721    redirects stdin, stdout, and stderr to /dev/null.  */
 722 extern int daemon __P ((int __nochdir, int __noclose));
 723
 724 #endif /* Use BSD || X/Open.  */
 725
 726
 727 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 728
 729 /* Return the current machine's Internet number.  */
 730 extern long int gethostid __P ((void));
 731
 732 /* Make all changes done to all files actually appear on disk.  */
 733 extern int sync __P ((void));
 734
 735
 736 /* Return the number of bytes in a page.  This is the system's page size,
 737    which is not necessarily the same as the hardware page size.  */
 738 extern int __getpagesize __P ((void));
 739 extern int getpagesize __P ((void));
 740
 741
 742 /* Truncate FILE to LENGTH bytes.  */
 743 extern int truncate __P ((__const char *__file, __off_t __length));
 744
 745 /* Truncate the file FD is open on to LENGTH bytes.  */
 746 extern int ftruncate __P ((int __fd, __off_t __length));
 747
 748
 749 /* Return the maximum number of file descriptors
 750    the current process could possibly have.  */
 751 extern int __getdtablesize __P ((void));
 752 extern int getdtablesize __P ((void));
 753
 754 #endif /* Use BSD || X/Open Unix.  */
 755
 756
 757 #if defined(__USE_MISC) || defined(__USE_XOPEN_EXTENDED)
 758
 759 /* Set the end of accessible data space (aka "the break") to ADDR.
 760    Returns zero on success and -1 for errors (with errno set).  */
 761 extern int __brk __P ((__ptr_t __addr));
 762 extern int brk __P ((__ptr_t __addr));
 763
 764 #define __need_ptrdiff_t
 765 #include <stddef.h>
 766
 767 /* Increase or decrease the end of accessible data space by DELTA bytes.
 768    If successful, returns the address the previous end of data space
 769    (i.e. the beginning of the new space, if DELTA > 0);
 770    returns (void *) -1 for errors (with errno set).  */
 771 extern __ptr_t __sbrk __P ((ptrdiff_t __delta));
 772 extern __ptr_t sbrk __P ((ptrdiff_t __delta));
 773 #endif
 774
 775
 776 #ifdef __USE_MISC
 777 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 778    This is completely system-dependent, and not often useful.
 779
 780    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 781    for errors; in many systems you cannot pass arguments or get return
 782    values for all system calls (`pipe', `fork', and `getppid' typically
 783    among them).
 784
 785    In Mach, all system calls take normal arguments and always return an
 786    error code (zero for success).  */
 787 extern long int syscall __P ((long int __sysno, ...));
 788
 789 #endif  /* Use misc.  */
 790
 791
 792 #if (defined (__USE_MISC) || defined (__USE_XOPEN_EXTENDED)) \
 793     && !defined (F_LOCK)
 794 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
 795    files consistent.  Some systems have them there and some here, and some
 796    software depends on the macros being defined without including both.  */
 797
 798 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 799    LEN is always relative to the current file position.
 800    The CMD argument is one of the following.  */
 801
 802 #define F_ULOCK 0       /* Unlock a previously locked region.  */
 803 #define F_LOCK  1       /* Lock a region for exclusive use.  */
 804 #define F_TLOCK 2       /* Test and lock a region for exclusive use.  */
 805 #define F_TEST  3       /* Test a region for other processes locks.  */
 806
 807 extern int lockf __P ((int __fd, int __cmd, __off_t __len));
 808 #endif /* Use misc and F_LOCK not already defined.  */
 809
 810
 811 #ifdef __USE_GNU
 812
 813 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
 814    set to EINTR.  */
 815
 816 #define TEMP_FAILURE_RETRY(expression) \
 817   (__extension__                                                              \
 818     ({ long int __result;                                                     \
 819        do __result = (long int) (expression);                                 \
 820        while (__result == -1L && errno == EINTR);                             \
 821        __result; }))                                                          \
 822
 823
 824 /* This variable is set nonzero at startup if the process's effective IDs
 825    differ from its real IDs, or it is otherwise indicated that extra
 826    security should be used.  When this is set the dynamic linker ignores
 827    the various environment variables that normally affect it.  */
 828 extern int __libc_enable_secure;
 829
 830 #endif
 831
 832 #ifdef __USE_POSIX199309
 833 /* Synchronize at least the data part of a file with the underlying
 834    media.  */
 835 extern int fdatasync __P ((int __fildes));
 836 #endif /* Use POSIX199309 */
 837
 838
 839 /* XPG4.2 specifies that prototypes for the encryption functions must
 840    be defined here.  */
 841 #ifdef  __USE_XOPEN
 842 /* Encrypt at most 8 characters from KEY using salt to perturb DES.  */
 843 extern char *crypt __P ((__const char *__key, __const char *__salt));
 844
 845 /* Setup DES tables according KEY.  */
 846 extern void setkey __P ((__const char *__key));
 847
 848 /* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt
 849    block in place.  */
 850 extern void encrypt __P ((char *__block, int __edflag));
 851
 852
 853 /* Swab pairs bytes in the first N bytes of the area pointed to by
 854    FROM and copy the result to TO.  The value of TO must not be in the
 855    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
 856    is without partner.  */
 857 extern void swab __P ((__const char *__from, char *__to, ssize_t __n));
 858 #endif
 859
 860 __END_DECLS
 861
 862 #endif /* unistd.h  */