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