posix/unistd.h

   1 /* Copyright (C) 1991,92,93,94,95,96,97,98 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 #define _UNISTD_H       1
  25
  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 ISO/IEC 9945-1 as of August, 1988 and
  34    extended by POSIX-1b (aka POSIX-4) and POSIX-1c (aka POSIX threads).  */
  35 #define _POSIX_VERSION  199506L
  36
  37 /* These are not #ifdef __USE_POSIX2 because they are
  38    in the theoretically application-owned namespace.  */
  39
  40 /* POSIX Standard approved as ISO/IEC 9945-2 as of December, 1993.  */
  41 #define _POSIX2_C_VERSION       199209L
  42
  43 /* The utilities on GNU systems also correspond to this version.  */
  44 #define _POSIX2_VERSION 199209L
  45
  46 /* If defined, the implementation supports the
  47    C Language Bindings Option.  */
  48 #define _POSIX2_C_BIND  1
  49
  50 /* If defined, the implementation supports the
  51    C Language Development Utilities Option.  */
  52 #define _POSIX2_C_DEV   1
  53
  54 /* If defined, the implementation supports the
  55    Software Development Utilities Option.  */
  56 #define _POSIX2_SW_DEV  1
  57
  58 /* If defined, the implementation supports the
  59    creation of locales with the localedef utility.  */
  60 #define _POSIX2_LOCALEDEF       1
  61
  62 /* X/Open version number to which the library conforms.  It is selectable.  */
  63 #ifdef __USE_UNIX98
  64 # define _XOPEN_VERSION 500
  65 #else
  66 # define _XOPEN_VERSION 4
  67 #endif
  68
  69 /* Commands and utilities from XPG4 are available.  */
  70 #define _XOPEN_XCU_VERSION      4
  71
  72 /* We are compatible with the old published standards as well.  */
  73 #define _XOPEN_XPG2     1
  74 #define _XOPEN_XPG3     1
  75 #define _XOPEN_XPG4     1
  76
  77 /* The X/Open Unix extensions are available.  */
  78 #define _XOPEN_UNIX     1
  79
  80 /* Encryption is present.  */
  81 #define _XOPEN_CRYPT    1
  82
  83 /* The enhanced internationalization capabilities according to XPG4.2
  84    are present.  */
  85 #define _XOPEN_ENH_I18N 1
  86
  87 /* The legacy interfaces are also available.  */
  88 #define _XOPEN_LEGACY   1
  89
  90
  91 /* Get values of POSIX options:
  92
  93    If these symbols are defined, the corresponding features are
  94    always available.  If not, they may be available sometimes.
  95    The current values can be obtained with `sysconf'.
  96
  97    _POSIX_JOB_CONTROL           Job control is supported.
  98    _POSIX_SAVED_IDS             Processes have a saved set-user-ID
  99                                 and a saved set-group-ID.
 100    _POSIX_REALTIME_SIGNALS      Real-time, queued signals are supported.
 101    _POSIX_PRIORITY_SCHEDULING   Priority scheduling is supported.
 102    _POSIX_TIMERS                POSIX.4 clocks and timers are supported.
 103    _POSIX_ASYNCHRONOUS_IO       Asynchronous I/O is supported.
 104    _POSIX_PRIORITIZED_IO        Prioritized asynchronous I/O is supported.
 105    _POSIX_SYNCHRONIZED_IO       Synchronizing file data is supported.
 106    _POSIX_FSYNC                 The fsync function is present.
 107    _POSIX_MAPPED_FILES          Mapping of files to memory is supported.
 108    _POSIX_MEMLOCK               Locking of all memory is supported.
 109    _POSIX_MEMLOCK_RANGE         Locking of ranges of memory is supported.
 110    _POSIX_MEMORY_PROTECTION     Setting of memory protections is supported.
 111    _POSIX_MESSAGE_PASSING       POSIX.4 message queues are supported.
 112    _POSIX_SEMAPHORES            POSIX.4 counting semaphores are supported.
 113    _POSIX_SHARED_MEMORY_OBJECTS POSIX.4 shared memory objects are supported.
 114    _POSIX_THREADS               POSIX.1c pthreads are supported.
 115    _POSIX_THREAD_ATTR_STACKADDR Thread stack address attribute option supported.
 116    _POSIX_THREAD_ATTR_STACKSIZE Thread stack size attribute option supported.
 117    _POSIX_THREAD_SAFE_FUNCTIONS Thread-safe functions are supported.
 118    _POSIX_THREAD_PRIORITY_SCHEDULING
 119                                 POSIX.1c thread execution scheduling supported.
 120    _POSIX_THREAD_PRIO_INHERIT   Thread priority inheritance option supported.
 121    _POSIX_THREAD_PRIO_PROTECT   Thread priority protection option supported.
 122    _POSIX_THREAD_PROCESS_SHARED Process-shared synchronization supported.
 123    _POSIX_PII                   Protocol-independent interfaces are supported.
 124    _POSIX_PII_XTI               XTI protocol-indep. interfaces are supported.
 125    _POSIX_PII_SOCKET            Socket protocol-indep. interfaces are supported.
 126    _POSIX_PII_INTERNET          Internet family of protocols supported.
 127    _POSIX_PII_INTERNET_STREAM   Connection-mode Internet protocol supported.
 128    _POSIX_PII_INTERNET_DGRAM    Connectionless Internet protocol supported.
 129    _POSIX_PII_OSI               ISO/OSI family of protocols supported.
 130    _POSIX_PII_OSI_COTS          Connection-mode ISO/OSI service supported.
 131    _POSIX_PII_OSI_CLTS          Connectionless ISO/OSI service supported.
 132    _POSIX_POLL                  Implementation supports `poll' function.
 133    _POSIX_SELECT                Implementation supports `select' and `pselect'.
 134
 135    _XOPEN_REALTIME              X/Open realtime support is available.
 136    _XOPEN_REALTIME_THREADS      X/Open realtime thread support is available.
 137    _XOPEN_SHM                   Shared memory interface according to XPG4.2.
 138
 139    _XBS5_ILP32_OFF32            Implementation provides environment with 32-bit
 140                                 int, long, pointer, and off_t types.
 141    _XBS5_ILP32_OFFBIG           Implementation provides environment with 32-bit
 142                                 int, long, and pointer and off_t with at least
 143                                 64 bits.
 144    _XBS5_LP64_OFF64             Implementation provides environment with 32-bit
 145                                 int, and 64-bit long, pointer, and off_t types.
 146    _XBS5_LPBIG_OFFBIG           Implementation provides environment with at
 147                                 least 32 bits int and long, pointer, and off_t
 148                                 with at least 64 bits.
 149
 150    If any of these symbols is defined as -1, the corresponding option is not
 151    true for any file.  If any is defined as other than -1, the corresponding
 152    option is true for all files.  If a symbol is not defined at all, the value
 153    for a specific file can be obtained from `pathconf' and `fpathconf'.
 154
 155    _POSIX_CHOWN_RESTRICTED      Only the super user can use `chown' to change
 156                                 the owner of a file.  `chown' can only be used
 157                                 to change the group ID of a file to a group of
 158                                 which the calling process is a member.
 159    _POSIX_NO_TRUNC              Pathname components longer than
 160                                 NAME_MAX generate an error.
 161    _POSIX_VDISABLE              If defined, if the value of an element of the
 162                                 `c_cc' member of `struct termios' is
 163                                 _POSIX_VDISABLE, no character will have the
 164                                 effect associated with that element.
 165    _POSIX_SYNC_IO               Synchronous I/O may be performed.
 166    _POSIX_ASYNC_IO              Asynchronous I/O may be performed.
 167    _POSIX_PRIO_IO               Prioritized Asynchronous I/O may be performed.
 168
 169    Support for the Large File Support interface is not generally available.
 170    If it is available the following constants are defined to one.
 171    _LFS64_LARGEFILE             Low-level I/O supports large files.
 172    _LFS64_STDIO                 Standard I/O supports large files.
 173    */
 174
 175 #include <bits/posix_opt.h>
 176
 177 /* Get the environment definitions from Unix98.  */
 178 #ifdef __USE_UNIX98
 179 # include <bits/environments.h>
 180 #endif
 181
 182 /* Standard file descriptors.  */
 183 #define STDIN_FILENO    0       /* Standard input.  */
 184 #define STDOUT_FILENO   1       /* Standard output.  */
 185 #define STDERR_FILENO   2       /* Standard error output.  */
 186
 187
 188 /* All functions that are not declared anywhere else.  */
 189
 190 #include <bits/types.h>
 191
 192 #ifndef ssize_t
 193 typedef __ssize_t ssize_t;
 194 # define ssize_t ssize_t
 195 #endif
 196
 197 #define __need_size_t
 198 #define __need_NULL
 199 #include <stddef.h>
 200
 201 #ifdef __USE_XOPEN
 202 /* The Single Unix specification says that some more types are
 203    available here.  */
 204 # ifndef gid_t
 205 typedef __gid_t gid_t;
 206 #  define gid_t gid_t
 207 # endif
 208
 209 # ifndef uid_t
 210 typedef __uid_t uid_t;
 211 #  define uid_t uid_t
 212 # endif
 213
 214 # ifndef off_t
 215 #  ifndef __USE_FILE_OFFSET64
 216 typedef __off_t off_t;
 217 #  else
 218 typedef __off64_t off_t;
 219 #  endif
 220 #  define off_t off_t
 221 # endif
 222 # if defined __USE_LARGEFILE64 && !defined off64_t
 223 typedef __off64_t off64_t;
 224 #  define off64_t off64_t
 225 # endif
 226
 227 # ifndef pid_t
 228 typedef __pid_t pid_t;
 229 #  define pid_t pid_t
 230 # endif
 231 #endif  /* X/Open */
 232
 233 #ifdef __USE_UNIX98
 234 # ifndef intptr_t
 235 typedef __intptr_t intptr_t;
 236 #  define intptr_t intptr_t
 237 # endif
 238 #endif  /* Unix98 */
 239
 240 /* Values for the second argument to access.
 241    These may be OR'd together.  */
 242 #define R_OK    4               /* Test for read permission.  */
 243 #define W_OK    2               /* Test for write permission.  */
 244 #define X_OK    1               /* Test for execute permission.  */
 245 #define F_OK    0               /* Test for existence.  */
 246
 247 /* Test for access to NAME using the real UID and real GID.  */
 248 extern int access __P ((__const char *__name, int __type));
 249
 250 #ifdef __USE_GNU
 251 /* Test for access to NAME using the effective UID and GID
 252    (as normal file operations use).  */
 253 extern int euidaccess __P ((__const char *__name, int __type));
 254 #endif
 255
 256
 257 /* Values for the WHENCE argument to lseek.  */
 258 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 259 # define SEEK_SET       0       /* Seek from beginning of file.  */
 260 # define SEEK_CUR       1       /* Seek from current position.  */
 261 # define SEEK_END       2       /* Seek from end of file.  */
 262 #endif
 263
 264 #if defined __USE_BSD && !defined L_SET
 265 /* Old BSD names for the same constants; just for compatibility.  */
 266 # define L_SET          SEEK_SET
 267 # define L_INCR         SEEK_CUR
 268 # define L_XTND         SEEK_END
 269 #endif
 270
 271
 272 /* Move FD's file position to OFFSET bytes from the
 273    beginning of the file (if WHENCE is SEEK_SET),
 274    the current position (if WHENCE is SEEK_CUR),
 275    or the end of the file (if WHENCE is SEEK_END).
 276    Return the new file position.  */
 277 extern __off_t __lseek __P ((int __fd, __off_t __offset, int __whence));
 278 #ifndef __USE_FILE_OFFSET64
 279 extern __off_t lseek __P ((int __fd, __off_t __offset, int __whence));
 280 #else
 281 # ifdef __REDIRECT
 282 extern __off64_t __REDIRECT (lseek,
 283                              __P ((int __fd, __off64_t __offset,
 284                                    int __whence)),
 285                              lseek64);
 286 # else
 287 #  define lseek lseek64
 288 # endif
 289 #endif
 290 #ifdef __USE_LARGEFILE64
 291 extern __off64_t lseek64 __P ((int __fd, __off64_t __offset, int __whence));
 292 #endif
 293
 294 /* Close the file descriptor FD.  */
 295 extern int __close __P ((int __fd));
 296 extern int close __P ((int __fd));
 297
 298 /* Read NBYTES into BUF from FD.  Return the
 299    number read, -1 for errors or 0 for EOF.  */
 300 extern ssize_t __read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 301 extern ssize_t read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 302
 303 /* Write N bytes of BUF to FD.  Return the number written, or -1.  */
 304 extern ssize_t __write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 305 extern ssize_t write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 306
 307 #ifdef __USE_UNIX98
 308 /* Read NBYTES into BUF from FD at the given position OFFSET without
 309    changing the file pointer.  Return the number read, -1 for errors
 310    or 0 for EOF.  */
 311 extern ssize_t __pread64 __P ((int __fd, __ptr_t __buf, size_t __nbytes,
 312                                __off64_t __offset));
 313 /* Write N bytes of BUF to FD at the given position OFFSET without
 314    changing the file pointer.  Return the number written, or -1.  */
 315 extern ssize_t __pwrite64 __P ((int __fd, __const __ptr_t __buf, size_t __n,
 316                                 __off64_t __offset));
 317
 318 # ifndef __USE_FILE_OFFSET64
 319 extern ssize_t pread __P ((int __fd, __ptr_t __buf, size_t __nbytes,
 320                            __off_t __offset));
 321 extern ssize_t pwrite __P ((int __fd, __const __ptr_t __buf, size_t __n,
 322                             __off_t __offset));
 323 # else
 324 #  ifdef __REDIRECT
 325 extern ssize_t __REDIRECT (pread, __P ((int __fd, __ptr_t __buf,
 326                                         size_t __nbytes,__off64_t __offset)),
 327                            pread64);
 328 extern ssize_t __REDIRECT (pwrite, __P ((int __fd, __const __ptr_t __buf,
 329                                          size_t __nbytes, __off64_t __offset)),
 330                         pwrite64);
 331 #  else
 332 #   define pread pread64
 333 #   define pwrite pwrite64
 334 #  endif
 335 # endif
 336
 337 # ifdef __USE_LARGEFILE64
 338 extern ssize_t pread64 __P ((int __fd, __ptr_t __buf, size_t __nbytes,
 339                              __off64_t __offset));
 340 extern ssize_t pwrite64 __P ((int __fd, __const __ptr_t __buf, size_t __n,
 341                               __off64_t __offset));
 342 # endif
 343 #endif
 344
 345 /* Create a one-way communication channel (pipe).
 346    If successful, two file descriptors are stored in PIPEDES;
 347    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 348    Returns 0 if successful, -1 if not.  */
 349 extern int pipe __P ((int __pipedes[2]));
 350
 351 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 352    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 353    The function returns the number of seconds remaining until the last
 354    alarm scheduled would have signaled, or zero if there wasn't one.
 355    There is no return value to indicate an error, but you can set `errno'
 356    to 0 and check its value after calling `alarm', and this might tell you.
 357    The signal may come late due to processor scheduling.  */
 358 extern unsigned int alarm __P ((unsigned int __seconds));
 359
 360 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 361    and is not ignored.  The function returns the number of seconds less
 362    than SECONDS which it actually slept (thus zero if it slept the full time).
 363    If a signal handler does a `longjmp' or modifies the handling of the
 364    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 365    signal afterwards is undefined.  There is no return value to indicate
 366    error, but if `sleep' returns SECONDS, it probably didn't work.  */
 367 extern unsigned int sleep __P ((unsigned int __seconds));
 368
 369 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 370 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 371    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 372    timer is reset to go off every INTERVAL microseconds thereafter.
 373    Returns the number of microseconds remaining before the alarm.  */
 374 extern unsigned int ualarm __P ((unsigned int __value,
 375                                  unsigned int __interval));
 376
 377 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 378    or ignored.  */
 379 extern void usleep __P ((unsigned int __useconds));
 380 #endif
 381
 382
 383 /* Suspend the process until a signal arrives.
 384    This always returns -1 and sets `errno' to EINTR.  */
 385 extern int pause __P ((void));
 386
 387
 388 /* Change the owner and group of FILE.  */
 389 extern int chown __P ((__const char *__file, __uid_t __owner,
 390                        __gid_t __group));
 391
 392 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 393 /* Change the owner and group of the file that FD is open on.  */
 394 extern int fchown __P ((int __fd, __uid_t __owner, __gid_t __group));
 395
 396
 397 /* Change owner and group of FILE, if it is a symbolic
 398    link the ownership of the symbolic link is changed.  */
 399 extern int lchown __P ((__const char *__file, __uid_t __owner,
 400                         __gid_t __group));
 401
 402 #endif /* Use BSD || X/Open Unix.  */
 403
 404 /* Change the process's working directory to PATH.  */
 405 extern int __chdir __P ((__const char *__path));
 406 extern int chdir __P ((__const char *__path));
 407
 408 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 409 /* Change the process's working directory to the one FD is open on.  */
 410 extern int fchdir __P ((int __fd));
 411 #endif
 412
 413 /* Get the pathname of the current working directory,
 414    and put it in SIZE bytes of BUF.  Returns NULL if the
 415    directory couldn't be determined or SIZE was too small.
 416    If successful, returns BUF.  In GNU, if BUF is NULL,
 417    an array is allocated with `malloc'; the array is SIZE
 418    bytes long, unless SIZE == 0, in which case it is as
 419    big as necessary.  */
 420 extern char *getcwd __P ((char *__buf, size_t __size));
 421
 422 #ifdef  __USE_GNU
 423 /* Return a malloc'd string containing the current directory name.
 424    If the environment variable `PWD' is set, and its value is correct,
 425    that value is used.  */
 426 extern char *get_current_dir_name __P ((void));
 427 #endif
 428
 429 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 430 /* Put the absolute pathname of the current working directory in BUF.
 431    If successful, return BUF.  If not, put an error message in
 432    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 433 extern char *getwd __P ((char *__buf));
 434 #endif
 435
 436
 437 /* Duplicate FD, returning a new file descriptor on the same file.  */
 438 extern int dup __P ((int __fd));
 439
 440 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 441 extern int dup2 __P ((int __fd, int __fd2));
 442
 443 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 444 extern char **__environ;
 445 #ifdef __USE_GNU
 446 extern char **environ;
 447 #endif
 448
 449
 450 /* Replace the current process, executing PATH with arguments ARGV and
 451    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 452 extern int execve __P ((__const char *__path, char *__const __argv[],
 453                         char *__const __envp[]));
 454
 455 #ifdef __USE_GNU
 456 /* Execute the file FD refers to, overlaying the running program image.
 457    ARGV and ENVP are passed to the new program, as for `execve'.  */
 458 extern int fexecve __P ((int __fd,
 459                          char *__const __argv[], char *__const __envp[]));
 460
 461 #endif
 462
 463
 464 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 465 extern int execv __P ((__const char *__path, char *__const __argv[]));
 466
 467 /* Execute PATH with all arguments after PATH until a NULL pointer,
 468    and the argument after that for environment.  */
 469 extern int execle __P ((__const char *__path, __const char *__arg, ...));
 470
 471 /* Execute PATH with all arguments after PATH until
 472    a NULL pointer and environment from `environ'.  */
 473 extern int execl __P ((__const char *__path, __const char *__arg, ...));
 474
 475 /* Execute FILE, searching in the `PATH' environment variable if it contains
 476    no slashes, with arguments ARGV and environment from `environ'.  */
 477 extern int execvp __P ((__const char *__file, char *__const __argv[]));
 478
 479 /* Execute FILE, searching in the `PATH' environment variable if
 480    it contains no slashes, with all arguments after FILE until a
 481    NULL pointer and environment from `environ'.  */
 482 extern int execlp __P ((__const char *__file, __const char *__arg, ...));
 483
 484
 485 #if defined __USE_MISC || defined __USE_XOPEN
 486 /* Add INC to priority of the current process.  */
 487 extern int nice __P ((int __inc));
 488 #endif
 489
 490
 491 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 492 extern void _exit __P ((int __status)) __attribute__ ((__noreturn__));
 493
 494
 495 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 496    the `_SC_*' symbols for the NAME argument to `sysconf';
 497    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 498 #include <bits/confname.h>
 499
 500 /* Get file-specific configuration information about PATH.  */
 501 extern long int pathconf __P ((__const char *__path, int __name));
 502
 503 /* Get file-specific configuration about descriptor FD.  */
 504 extern long int fpathconf __P ((int __fd, int __name));
 505
 506 /* Get the value of the system variable NAME.  */
 507 extern long int sysconf __P ((int __name));
 508
 509 #ifdef  __USE_POSIX2
 510 /* Get the value of the string-valued system variable NAME.  */
 511 extern size_t confstr __P ((int __name, char *__buf, size_t __len));
 512 #endif
 513
 514
 515 /* Get the process ID of the calling process.  */
 516 extern __pid_t __getpid __P ((void));
 517 extern __pid_t getpid __P ((void));
 518
 519 /* Get the process ID of the calling process's parent.  */
 520 extern __pid_t getppid __P ((void));
 521
 522 /* Get the process group ID of the calling process.
 523    This function is different on old BSD. */
 524 #ifndef __FAVOR_BSD
 525 extern __pid_t getpgrp __P ((void));
 526 #else
 527 # ifdef __REDIRECT
 528 extern __pid_t __REDIRECT (getpgrp, __P ((__pid_t __pid)), __getpgid);
 529 # else
 530 #  define getpgrp __getpgid
 531 # endif
 532 #endif
 533
 534 /* Get the process group ID of process PID.  */
 535 extern __pid_t __getpgid __P ((__pid_t __pid));
 536 #ifdef __USE_XOPEN_EXTENDED
 537 extern __pid_t getpgid __P ((__pid_t __pid));
 538 #endif
 539
 540
 541 /* Set the process group ID of the process matching PID to PGID.
 542    If PID is zero, the current process's process group ID is set.
 543    If PGID is zero, the process ID of the process is used.  */
 544 extern int __setpgid __P ((__pid_t __pid, __pid_t __pgid));
 545 extern int setpgid __P ((__pid_t __pid, __pid_t __pgid));
 546
 547 #if defined __USE_SVID || defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 548 /* Both System V and BSD have `setpgrp' functions, but with different
 549    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 550    (above).  The System V function takes no arguments and puts the calling
 551    process in its on group like `setpgid (0, 0)'.
 552
 553    New programs should always use `setpgid' instead.
 554
 555    The default in GNU is to provide the System V function.  The BSD
 556    function is available under -D_BSD_SOURCE.  */
 557
 558 # ifndef __FAVOR_BSD
 559
 560 /* Set the process group ID of the calling process to its own PID.
 561    This is exactly the same as `setpgid (0, 0)'.  */
 562 extern int setpgrp __P ((void));
 563
 564 # else
 565
 566 /* Another name for `setpgid' (above).  */
 567 #  ifdef __REDIRECT
 568 extern int __REDIRECT (setpgrp, __P ((__pid_t __pid, __pid_t __pgrp)),
 569                        setpgid);
 570 #  else
 571 #   define setpgrp setpgid
 572 #  endif
 573
 574 # endif /* Favor BSD.  */
 575 #endif  /* Use SVID or BSD.  */
 576
 577 /* Create a new session with the calling process as its leader.
 578    The process group IDs of the session and the calling process
 579    are set to the process ID of the calling process, which is returned.  */
 580 extern __pid_t setsid __P ((void));
 581
 582 #ifdef __USE_XOPEN_EXTENDED
 583 /* Return the session ID of the given process.  */
 584 extern __pid_t getsid __P ((__pid_t __pid));
 585 #endif
 586
 587 /* Get the real user ID of the calling process.  */
 588 extern __uid_t getuid __P ((void));
 589
 590 /* Get the effective user ID of the calling process.  */
 591 extern __uid_t geteuid __P ((void));
 592
 593 /* Get the real group ID of the calling process.  */
 594 extern __gid_t getgid __P ((void));
 595
 596 /* Get the effective group ID of the calling process.  */
 597 extern __gid_t getegid __P ((void));
 598
 599 /* If SIZE is zero, return the number of supplementary groups
 600    the calling process is in.  Otherwise, fill in the group IDs
 601    of its supplementary groups in LIST and return the number written.  */
 602 extern int getgroups __P ((int __size, __gid_t __list[]));
 603
 604 #ifdef  __USE_GNU
 605 /* Return nonzero iff the calling process is in group GID.  */
 606 extern int group_member __P ((__gid_t __gid));
 607 #endif
 608
 609 /* Set the user ID of the calling process to UID.
 610    If the calling process is the super-user, set the real
 611    and effective user IDs, and the saved set-user-ID to UID;
 612    if not, the effective user ID is set to UID.  */
 613 extern int setuid __P ((__uid_t __uid));
 614
 615 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 616 /* Set the real user ID of the calling process to RUID,
 617    and the effective user ID of the calling process to EUID.  */
 618 extern int setreuid __P ((__uid_t __ruid, __uid_t __euid));
 619 #endif
 620
 621 #ifdef  __USE_BSD
 622 /* Set the effective user ID of the calling process to UID.  */
 623 extern int seteuid __P ((__uid_t __uid));
 624 #endif /* Use BSD.  */
 625
 626 /* Set the group ID of the calling process to GID.
 627    If the calling process is the super-user, set the real
 628    and effective group IDs, and the saved set-group-ID to GID;
 629    if not, the effective group ID is set to GID.  */
 630 extern int setgid __P ((__gid_t __gid));
 631
 632 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 633 /* Set the real group ID of the calling process to RGID,
 634    and the effective group ID of the calling process to EGID.  */
 635 extern int setregid __P ((__gid_t __rgid, __gid_t __egid));
 636 #endif
 637
 638 #ifdef __USE_BSD
 639 /* Set the effective group ID of the calling process to GID.  */
 640 extern int setegid __P ((__gid_t __gid));
 641 #endif /* Use BSD.  */
 642
 643
 644 /* Clone the calling process, creating an exact copy.
 645    Return -1 for errors, 0 to the new process,
 646    and the process ID of the new process to the old process.  */
 647 extern __pid_t __fork __P ((void));
 648 extern __pid_t fork __P ((void));
 649
 650 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 651 /* Clone the calling process, but without copying the whole address space.
 652    The calling process is suspended until the new process exits or is
 653    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 654    and the process ID of the new process to the old process.  */
 655 extern __pid_t vfork __P ((void));
 656 #endif /* Use BSD. */
 657
 658
 659 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 660    The returned storage is good only until the next call to this function.  */
 661 extern char *ttyname __P ((int __fd));
 662
 663 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 664    open on in BUF.  Return 0 on success, otherwise an error number.  */
 665 extern int ttyname_r __P ((int __fd, char *__buf, size_t __buflen));
 666
 667 /* Return 1 if FD is a valid descriptor associated
 668    with a terminal, zero if not.  */
 669 extern int isatty __P ((int __fd));
 670
 671 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 672 /* Return the index into the active-logins file (utmp) for
 673    the controlling terminal.  */
 674 extern int ttyslot __P ((void));
 675 #endif
 676
 677
 678 /* Make a link to FROM named TO.  */
 679 extern int link __P ((__const char *__from, __const char *__to));
 680
 681 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 682 /* Make a symbolic link to FROM named TO.  */
 683 extern int symlink __P ((__const char *__from, __const char *__to));
 684
 685 /* Read the contents of the symbolic link PATH into no more than
 686    LEN bytes of BUF.  The contents are not null-terminated.
 687    Returns the number of characters read, or -1 for errors.  */
 688 extern int readlink __P ((__const char *__path, char *__buf, size_t __len));
 689 #endif /* Use BSD.  */
 690
 691 /* Remove the link NAME.  */
 692 extern int unlink __P ((__const char *__name));
 693
 694 /* Remove the directory PATH.  */
 695 extern int rmdir __P ((__const char *__path));
 696
 697
 698 /* Return the foreground process group ID of FD.  */
 699 extern __pid_t tcgetpgrp __P ((int __fd));
 700
 701 /* Set the foreground process group ID of FD set PGRP_ID.  */
 702 extern int tcsetpgrp __P ((int __fd, __pid_t __pgrp_id));
 703
 704
 705 /* Return the login name of the user.  */
 706 extern char *getlogin __P ((void));
 707 #ifdef __USE_REENTRANT
 708 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 709    If it cannot be determined or some other error occurred, return the error
 710    code.  Otherwise return 0.  */
 711 extern int getlogin_r __P ((char *__name, size_t __name_len));
 712 #endif
 713
 714 #ifdef  __USE_BSD
 715 /* Set the login name returned by `getlogin'.  */
 716 extern int setlogin __P ((__const char *__name));
 717 #endif
 718
 719
 720 #ifdef  __USE_POSIX2
 721 /* Get definitions and prototypes for functions to process the
 722    arguments in ARGV (ARGC of them, minus the program name) for
 723    options given in OPTS.  */
 724 # define __need_getopt
 725 # include <getopt.h>
 726 #endif
 727
 728
 729 #if defined __USE_BSD || defined __USE_XOPEN
 730
 731 /* Put the name of the current host in no more than LEN bytes of NAME.
 732    The result is null-terminated if LEN is large enough for the full
 733    name and the terminator.  */
 734 extern int gethostname __P ((char *__name, size_t __len));
 735
 736 /* Set the name of the current host to NAME, which is LEN bytes long.
 737    This call is restricted to the super-user.  */
 738 extern int sethostname __P ((__const char *__name, size_t __len));
 739
 740 /* Set the current machine's Internet number to ID.
 741    This call is restricted to the super-user.  */
 742 extern int sethostid __P ((long int __id));
 743
 744
 745 /* Get and set the NIS (aka YP) domain name, if any.
 746    Called just like `gethostname' and `sethostname'.
 747    The NIS domain name is usually the empty string when not using NIS.  */
 748 extern int getdomainname __P ((char *__name, size_t __len));
 749 extern int setdomainname __P ((__const char *__name, size_t __len));
 750
 751
 752 /* Make all changes done to FD actually appear on disk.  */
 753 extern int fsync __P ((int __fd));
 754
 755
 756 /* Revoke access permissions to all processes currently communicating
 757    with the control terminal, and then send a SIGHUP signal to the process
 758    group of the control terminal.  */
 759 extern int vhangup __P ((void));
 760
 761 /* Revoke the access of all descriptors currently open on FILE.  */
 762 extern int revoke __P ((__const char *__file));
 763
 764
 765 /* Enable statistical profiling, writing samples of the PC into at most
 766    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 767    is enabled, the system examines the user PC and increments
 768    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 769    disable profiling.  Returns zero on success, -1 on error.  */
 770 extern int profil __P ((unsigned short int *__sample_buffer, size_t __size,
 771                         size_t __offset, unsigned int __scale));
 772
 773
 774 /* Turn accounting on if NAME is an existing file.  The system will then write
 775    a record for each process as it terminates, to this file.  If NAME is NULL,
 776    turn accounting off.  This call is restricted to the super-user.  */
 777 extern int acct __P ((__const char *__name));
 778
 779 /* Make PATH be the root directory (the starting point for absolute paths).
 780    This call is restricted to the super-user.  */
 781 extern int chroot __P ((__const char *__path));
 782
 783
 784 /* Successive calls return the shells listed in `/etc/shells'.  */
 785 extern char *getusershell __P ((void));
 786 extern void endusershell __P ((void)); /* Discard cached info.  */
 787 extern void setusershell __P ((void)); /* Rewind and re-read the file.  */
 788
 789
 790 /* Prompt with PROMPT and read a string from the terminal without echoing.
 791    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 792 extern char *getpass __P ((__const char *__prompt));
 793
 794 /* Put the program in the background, and dissociate from the controlling
 795    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 796    redirects stdin, stdout, and stderr to /dev/null.  */
 797 extern int daemon __P ((int __nochdir, int __noclose));
 798
 799 #endif /* Use BSD || X/Open.  */
 800
 801
 802 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 803
 804 /* Return the current machine's Internet number.  */
 805 extern long int gethostid __P ((void));
 806
 807 /* Make all changes done to all files actually appear on disk.  */
 808 extern int sync __P ((void));
 809
 810
 811 /* Return the number of bytes in a page.  This is the system's page size,
 812    which is not necessarily the same as the hardware page size.  */
 813 extern int __getpagesize __P ((void));
 814 extern int getpagesize __P ((void));
 815
 816
 817 /* Truncate FILE to LENGTH bytes.  */
 818 #ifndef __USE_FILE_OFFSET64
 819 extern int truncate __P ((__const char *__file, __off_t __length));
 820 #else
 821 # ifdef __REDIRECT
 822 extern int __REDIRECT (truncate,
 823                        __P ((__const char *__file, __off64_t __length)),
 824                        truncate64);
 825 # else
 826 #  define truncate truncate64
 827 # endif
 828 #endif
 829 #ifdef __USE_LARGEFILE64
 830 extern int truncate64 __P ((__const char *__file, __off64_t __length));
 831 #endif
 832
 833 /* Truncate the file FD is open on to LENGTH bytes.  */
 834 extern int __ftruncate __P ((int __fd, __off_t __length));
 835 #ifndef __USE_FILE_OFFSET64
 836 extern int ftruncate __P ((int __fd, __off_t __length));
 837 #else
 838 # ifdef __REDIRECT
 839 extern int __REDIRECT (ftruncate, __P ((int __fd, __off64_t __length)),
 840                        ftruncate64);
 841 # else
 842 #  define ftruncate ftruncate64
 843 # endif
 844 #endif
 845 #ifdef __USE_LARGEFILE64
 846 extern int ftruncate64 __P ((int __fd, __off64_t __length));
 847 #endif
 848
 849
 850 /* Return the maximum number of file descriptors
 851    the current process could possibly have.  */
 852 extern int getdtablesize __P ((void));
 853
 854 #endif /* Use BSD || X/Open Unix.  */
 855
 856
 857 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 858
 859 /* Set the end of accessible data space (aka "the break") to ADDR.
 860    Returns zero on success and -1 for errors (with errno set).  */
 861 extern int brk __P ((__ptr_t __addr));
 862
 863 # define __need_ptrdiff_t
 864 # include <stddef.h>
 865
 866 /* Increase or decrease the end of accessible data space by DELTA bytes.
 867    If successful, returns the address the previous end of data space
 868    (i.e. the beginning of the new space, if DELTA > 0);
 869    returns (void *) -1 for errors (with errno set).  */
 870 extern __ptr_t __sbrk __P ((ptrdiff_t __delta));
 871 extern __ptr_t sbrk __P ((ptrdiff_t __delta));
 872 #endif
 873
 874
 875 #ifdef __USE_MISC
 876 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 877    This is completely system-dependent, and not often useful.
 878
 879    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 880    for errors; in many systems you cannot pass arguments or get return
 881    values for all system calls (`pipe', `fork', and `getppid' typically
 882    among them).
 883
 884    In Mach, all system calls take normal arguments and always return an
 885    error code (zero for success).  */
 886 extern long int syscall __P ((long int __sysno, ...));
 887
 888 #endif  /* Use misc.  */
 889
 890
 891 #if (defined __USE_MISC || defined __USE_XOPEN_EXTENDED) && !defined F_LOCK
 892 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
 893    files consistent.  Some systems have them there and some here, and some
 894    software depends on the macros being defined without including both.  */
 895
 896 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 897    LEN is always relative to the current file position.
 898    The CMD argument is one of the following.  */
 899
 900 # define F_ULOCK 0      /* Unlock a previously locked region.  */
 901 # define F_LOCK  1      /* Lock a region for exclusive use.  */
 902 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
 903 # define F_TEST  3      /* Test a region for other processes locks.  */
 904
 905 # ifndef __USE_FILE_OFFSET64
 906 extern int lockf __P ((int __fd, int __cmd, __off_t __len));
 907 # else
 908 #  ifdef __REDIRECT
 909 extern int __REDIRECT (lockf, __P ((int __fd, int __cmd, __off64_t __len)),
 910                        lockf64);
 911 #  else
 912 #   define lockf lockf64
 913 #  endif
 914 # endif
 915 # ifdef __USE_LARGEFILE64
 916 extern int lockf64 __P ((int __fd, int __cmd, __off64_t __len));
 917 # endif
 918 #endif /* Use misc and F_LOCK not already defined.  */
 919
 920
 921 #ifdef __USE_GNU
 922
 923 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
 924    set to EINTR.  */
 925
 926 # define TEMP_FAILURE_RETRY(expression) \
 927   (__extension__                                                              \
 928     ({ long int __result;                                                     \
 929        do __result = (long int) (expression);                                 \
 930        while (__result == -1L && errno == EINTR);                             \
 931        __result; }))                                                          \
 932
 933
 934 /* This variable is set nonzero at startup if the process's effective
 935    IDs differ from its real IDs, or it is otherwise indicated that
 936    extra security should be used.  When this is set the dynamic linker
 937    and some functions contained in the C library ignore various
 938    environment variables that normally affect them.  */
 939 extern int __libc_enable_secure;
 940
 941 #endif
 942
 943 #if defined __USE_POSIX199309 || defined __USE_UNIX98
 944 /* Synchronize at least the data part of a file with the underlying
 945    media.  */
 946 extern int fdatasync __P ((int __fildes));
 947 #endif /* Use POSIX199309 */
 948
 949
 950 /* XPG4.2 specifies that prototypes for the encryption functions must
 951    be defined here.  */
 952 #ifdef  __USE_XOPEN
 953 /* Encrypt at most 8 characters from KEY using salt to perturb DES.  */
 954 extern char *crypt __P ((__const char *__key, __const char *__salt));
 955
 956 /* Setup DES tables according KEY.  */
 957 extern void setkey __P ((__const char *__key));
 958
 959 /* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt
 960    block in place.  */
 961 extern void encrypt __P ((char *__block, int __edflag));
 962
 963
 964 /* Swab pairs bytes in the first N bytes of the area pointed to by
 965    FROM and copy the result to TO.  The value of TO must not be in the
 966    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
 967    is without partner.  */
 968 extern void swab __P ((__const __ptr_t __from, __ptr_t __to, ssize_t __n));
 969 #endif
 970
 971
 972 /* The Single Unix specification, version 2, demands these prototypes
 973    to be here.  They are also found in <stdio.h>.  */
 974 #ifdef __USE_XOPEN
 975 /* Return the name of the controlling terminal.  */
 976 extern char *ctermid __P ((char *__s));
 977
 978 /* Return the name of the current user.  This function should not be
 979    used and might go away some time.  */
 980 extern char *cuserid __P ((char *__s));
 981
 982 /* Rename file OLD to NEW.  */
 983 extern int rename __P ((__const char *__old, __const char *__new));
 984 #endif
 985
 986
 987 #ifdef __USE_POSIX199309
 988 /* This function is only available if the system has POSIX threads.  */
 989
 990 /* Install handlers to be called when a new process is created with FORK.
 991    The PREPARE handler is called in the parent process just before performing
 992    FORK. The PARENT handler is called in the parent process just after FORK.
 993    The CHILD handler is called in the child process.  Each of the three
 994    handlers can be NULL, meaning that no handler needs to be called at that
 995    point.
 996    PTHREAD_ATFORK can be called several times, in which case the PREPARE
 997    handlers are called in LIFO order (last added with PTHREAD_ATFORK,
 998    first called before FORK), and the PARENT and CHILD handlers are called
 999    in FIFO (first added, first called). */
1000 extern int pthread_atfork __P ((void (*__prepare) (void),
1001                                 void (*__parent) (void),
1002                                 void (*__child) (void)));
1003 #endif
1004
1005 __END_DECLS
1006
1007 #endif /* unistd.h  */