posix/unistd.h

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96, 97 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 /*
  20  *      POSIX Standard: 2.10 Symbolic Constants         <unistd.h>
  21  */
  22
  23 #ifndef _UNISTD_H
  24 #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 /* If defined, the implementation supports the
  44    C Language Bindings Option.  */
  45 #define _POSIX2_C_BIND  1
  46
  47 /* If defined, the implementation supports the
  48    C Language Development Utilities Option.  */
  49 #define _POSIX2_C_DEV   1
  50
  51 /* If defined, the implementation supports the
  52    Software Development Utilities Option.  */
  53 #define _POSIX2_SW_DEV  1
  54
  55 /* If defined, the implementation supports the
  56    creation of locales with the localedef utility.  */
  57 #define _POSIX2_LOCALEDEF       1
  58
  59 /* Library conforms to X/Open version 4.  */
  60 #define _XOPEN_VERSION  4
  61
  62 /* Commands and utilities from XPG4 are available.  */
  63 #define _XOPEN_XCU_VERSION      4
  64
  65 /* We are compatible with the old published standards as well.  */
  66 #define _XOPEN_XPG2     1
  67 #define _XOPEN_XPG3     1
  68 #define _XOPEN_XPG4     1
  69
  70 /* The X/Open Unix extensions are available.  */
  71 #define _XOPEN_UNIX     1
  72
  73 /* Encryption is present.  */
  74 #define _XOPEN_CRYPT    1
  75
  76 /* The enhanced internationalization capabilities according to XPG4.2
  77    are present.  */
  78 #define _XOPEN_ENH_I18N 1
  79
  80
  81 /* Get values of POSIX options:
  82
  83    If these symbols are defined, the corresponding features are
  84    always available.  If not, they may be available sometimes.
  85    The current values can be obtained with `sysconf'.
  86
  87    _POSIX_JOB_CONTROL           Job control is supported.
  88    _POSIX_SAVED_IDS             Processes have a saved set-user-ID
  89                                 and a saved set-group-ID.
  90    _POSIX_REALTIME_SIGNALS      Real-time, queued signals are supported.
  91    _POSIX_PRIORITY_SCHEDULING   Priority scheduling is supported.
  92    _POSIX_TIMERS                POSIX.4 clocks and timers are supported.
  93    _POSIX_ASYNCHRONOUS_IO       Asynchronous I/O is supported.
  94    _POSIX_PRIORITIZED_IO        Prioritized asynchronous I/O is supported.
  95    _POSIX_SYNCHRONIZED_IO       Synchronizing file data is supported.
  96    _POSIX_FSYNC                 The fsync function is present.
  97    _POSIX_MAPPED_FILES          Mapping of files to memory is supported.
  98    _POSIX_MEMLOCK               Locking of all memory is supported.
  99    _POSIX_MEMLOCK_RANGE         Locking of ranges of memory is supported.
 100    _POSIX_MEMORY_PROTECTION     Setting of memory protections is supported.
 101    _POSIX_MESSAGE_PASSING       POSIX.4 message queues are supported.
 102    _POSIX_SEMAPHORES            POSIX.4 counting semaphores are supported.
 103    _POSIX_SHARED_MEMORY_OBJECTS POSIX.4 shared memory objects are supported.
 104    _POSIX_PII                   Protocol-independent interfaces are supported.
 105    _POSIX_PII_XTI               XTI protocol-indep. interfaces are supported.
 106    _POSIX_PII_SOCKET            Socket protocol-indep. interfaces are supported.
 107    _POSIX_PII_INTERNET          Internet family of protocols supported.
 108    _POSIX_PII_INTERNET_STREAM   Connection-mode Internet protocol supported.
 109    _POSIX_PII_INTERNET_DGRAM    Connectionless Internet protocol supported.
 110    _POSIX_PII_OSI               ISO/OSI family of protocols supported.
 111    _POSIX_PII_OSI_COTS          Connection-mode ISO/OSI service supported.
 112    _POSIX_PII_OSI_CLTS          Connectionless ISO/OSI service supported.
 113    _POSIX_POLL                  Implementation supports `poll' function.
 114    _POSIX_SELECT                Implementation supports `select' and `pselect'.
 115
 116    _XOPEN_SHM                   Shared memory interface according to XPG4.2.
 117
 118    If any of these symbols is defined as -1, the corresponding option is not
 119    true for any file.  If any is defined as other than -1, the corresponding
 120    option is true for all files.  If a symbol is not defined at all, the value
 121    for a specific file can be obtained from `pathconf' and `fpathconf'.
 122
 123    _POSIX_CHOWN_RESTRICTED      Only the super user can use `chown' to change
 124                                 the owner of a file.  `chown' can only be used
 125                                 to change the group ID of a file to a group of
 126                                 which the calling process is a member.
 127    _POSIX_NO_TRUNC              Pathname components longer than
 128                                 NAME_MAX generate an error.
 129    _POSIX_VDISABLE              If defined, if the value of an element of the
 130                                 `c_cc' member of `struct termios' is
 131                                 _POSIX_VDISABLE, no character will have the
 132                                 effect associated with that element.
 133    _POSIX_SYNC_IO               Synchronous I/O may be performed.
 134    _POSIX_ASYNC_IO              Asynchronous I/O may be performed.
 135    _POSIX_PRIO_IO               Prioritized Asynchronous I/O may be performed.
 136    */
 137
 138 #include <bits/posix_opt.h>
 139
 140
 141 /* Standard file descriptors.  */
 142 #define STDIN_FILENO    0       /* Standard input.  */
 143 #define STDOUT_FILENO   1       /* Standard output.  */
 144 #define STDERR_FILENO   2       /* Standard error output.  */
 145
 146
 147 /* All functions that are not declared anywhere else.  */
 148
 149 #include <bits/types.h>
 150
 151 #ifndef ssize_t
 152 typedef __ssize_t ssize_t;
 153 #define ssize_t ssize_t
 154 #endif
 155
 156 #define __need_size_t
 157 #define __need_NULL
 158 #include <stddef.h>
 159
 160
 161 /* Values for the second argument to access.
 162    These may be OR'd together.  */
 163 #define R_OK    4               /* Test for read permission.  */
 164 #define W_OK    2               /* Test for write permission.  */
 165 #define X_OK    1               /* Test for execute permission.  */
 166 #define F_OK    0               /* Test for existence.  */
 167
 168 /* Test for access to NAME using the real UID and real GID.  */
 169 extern int __access __P ((__const char *__name, int __type));
 170 extern int access __P ((__const char *__name, int __type));
 171
 172 #ifdef __USE_GNU
 173 /* Test for access to NAME using the effective UID and GID
 174    (as normal file operations use).  */
 175 extern int __euidaccess __P ((__const char *__name, int __type));
 176 extern int euidaccess __P ((__const char *__name, int __type));
 177 #endif
 178
 179
 180 /* Values for the WHENCE argument to lseek.  */
 181 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 182 #define SEEK_SET        0       /* Seek from beginning of file.  */
 183 #define SEEK_CUR        1       /* Seek from current position.  */
 184 #define SEEK_END        2       /* Seek from end of file.  */
 185 #endif
 186
 187 #if defined __USE_BSD && !defined L_SET
 188 /* Old BSD names for the same constants; just for compatibility.  */
 189 #define L_SET           SEEK_SET
 190 #define L_INCR          SEEK_CUR
 191 #define L_XTND          SEEK_END
 192 #endif
 193
 194
 195 /* Move FD's file position to OFFSET bytes from the
 196    beginning of the file (if WHENCE is SEEK_SET),
 197    the current position (if WHENCE is SEEK_CUR),
 198    or the end of the file (if WHENCE is SEEK_END).
 199    Return the new file position.  */
 200 extern __off_t __lseek __P ((int __fd, __off_t __offset, int __whence));
 201 extern __off_t lseek __P ((int __fd, __off_t __offset, int __whence));
 202
 203 /* Close the file descriptor FD.  */
 204 extern int __close __P ((int __fd));
 205 extern int close __P ((int __fd));
 206
 207 /* Read NBYTES into BUF from FD.  Return the
 208    number read, -1 for errors or 0 for EOF.  */
 209 extern ssize_t __read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 210 extern ssize_t read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 211
 212 /* Write N bytes of BUF to FD.  Return the number written, or -1.  */
 213 extern ssize_t __write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 214 extern ssize_t write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 215
 216
 217 /* Create a one-way communication channel (pipe).
 218    If successful, two file descriptors are stored in PIPEDES;
 219    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 220    Returns 0 if successful, -1 if not.  */
 221 extern int __pipe __P ((int __pipedes[2]));
 222 extern int pipe __P ((int __pipedes[2]));
 223
 224 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 225    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 226    The function returns the number of seconds remaining until the last
 227    alarm scheduled would have signaled, or zero if there wasn't one.
 228    There is no return value to indicate an error, but you can set `errno'
 229    to 0 and check its value after calling `alarm', and this might tell you.
 230    The signal may come late due to processor scheduling.  */
 231 extern unsigned int alarm __P ((unsigned int __seconds));
 232
 233 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 234    and is not ignored.  The function returns the number of seconds less
 235    than SECONDS which it actually slept (thus zero if it slept the full time).
 236    If a signal handler does a `longjmp' or modifies the handling of the
 237    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 238    signal afterwards is undefined.  There is no return value to indicate
 239    error, but if `sleep' returns SECONDS, it probably didn't work.  */
 240 extern unsigned int __sleep __P ((unsigned int __seconds));
 241 extern unsigned int sleep __P ((unsigned int __seconds));
 242
 243 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 244 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 245    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 246    timer is reset to go off every INTERVAL microseconds thereafter.
 247    Returns the number of microseconds remaining before the alarm.  */
 248 extern unsigned int ualarm __P ((unsigned int __value,
 249                                  unsigned int __interval));
 250
 251 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 252    or ignored.  */
 253 extern void usleep __P ((unsigned int __useconds));
 254 #endif
 255
 256
 257 /* Suspend the process until a signal arrives.
 258    This always returns -1 and sets `errno' to EINTR.  */
 259 extern int pause __P ((void));
 260
 261
 262 /* Change the owner and group of FILE.  */
 263 extern int __chown __P ((__const char *__file,
 264                          __uid_t __owner, __gid_t __group));
 265 extern int chown __P ((__const char *__file,
 266                        __uid_t __owner, __gid_t __group));
 267
 268 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 269 /* Change the owner and group of the file that FD is open on.  */
 270 extern int __fchown __P ((int __fd,
 271                           __uid_t __owner, __gid_t __group));
 272 extern int fchown __P ((int __fd,
 273                         __uid_t __owner, __gid_t __group));
 274
 275
 276 /* Change owner and group of FILE, if it is a symbolic
 277    link the ownership of the symbolic link is changed.  */
 278 extern int __lchown __P ((__const char *__file, __uid_t __owner,
 279                           __gid_t __group));
 280 extern int lchown __P ((__const char *__file, __uid_t __owner,
 281                         __gid_t __group));
 282
 283 #endif /* Use BSD || X/Open Unix.  */
 284
 285 /* Change the process's working directory to PATH.  */
 286 extern int __chdir __P ((__const char *__path));
 287 extern int chdir __P ((__const char *__path));
 288
 289 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 290 /* Change the process's working directory to the one FD is open on.  */
 291 extern int __fchdir __P ((int __fd));
 292 extern int fchdir __P ((int __fd));
 293 #endif
 294
 295 /* Get the pathname of the current working directory,
 296    and put it in SIZE bytes of BUF.  Returns NULL if the
 297    directory couldn't be determined or SIZE was too small.
 298    If successful, returns BUF.  In GNU, if BUF is NULL,
 299    an array is allocated with `malloc'; the array is SIZE
 300    bytes long, unless SIZE == 0, in which case it is as
 301    big as necessary.  */
 302 extern char *__getcwd __P ((char *__buf, size_t __size));
 303 extern char *getcwd __P ((char *__buf, size_t __size));
 304
 305 #ifdef  __USE_GNU
 306 /* Return a malloc'd string containing the current directory name.
 307    If the environment variable `PWD' is set, and its value is correct,
 308    that value is used.  */
 309 extern char *get_current_dir_name __P ((void));
 310
 311 /* Get the canonical absolute name of the named directory, and put it in SIZE
 312    bytes of BUF.  Returns NULL if the directory couldn't be determined or
 313    SIZE was too small.  If successful, returns BUF.  In GNU, if BUF is
 314    NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
 315    unless SIZE <= 0, in which case it is as big as necessary.  */
 316
 317 char *__canonicalize_directory_name_internal __P ((__const char *__thisdir,
 318                                                    char *__buf,
 319                                                    size_t __size));
 320 #endif
 321
 322 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 323 /* Put the absolute pathname of the current working directory in BUF.
 324    If successful, return BUF.  If not, put an error message in
 325    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 326 extern char *getwd __P ((char *__buf));
 327 #endif
 328
 329
 330 /* Duplicate FD, returning a new file descriptor on the same file.  */
 331 extern int __dup __P ((int __fd));
 332 extern int dup __P ((int __fd));
 333
 334 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 335 extern int __dup2 __P ((int __fd, int __fd2));
 336 extern int dup2 __P ((int __fd, int __fd2));
 337
 338 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 339 extern char **__environ;
 340 #ifdef __USE_GNU
 341 extern char **environ;
 342 #endif
 343
 344
 345 /* Replace the current process, executing PATH with arguments ARGV and
 346    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 347 extern int __execve __P ((__const char *__path, char *__const __argv[],
 348                           char *__const __envp[]));
 349 extern int execve __P ((__const char *__path, char *__const __argv[],
 350                         char *__const __envp[]));
 351
 352 #ifdef __USE_GNU
 353 /* Execute the file FD refers to, overlaying the running program image.
 354    ARGV and ENVP are passed to the new program, as for `execve'.  */
 355 extern int fexecve __P ((int __fd,
 356                          char *__const __argv[], char *__const __envp[]));
 357
 358 #endif
 359
 360
 361 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 362 extern int execv __P ((__const char *__path, char *__const __argv[]));
 363
 364 /* Execute PATH with all arguments after PATH until a NULL pointer,
 365    and the argument after that for environment.  */
 366 extern int execle __P ((__const char *__path, __const char *__arg, ...));
 367
 368 /* Execute PATH with all arguments after PATH until
 369    a NULL pointer and environment from `environ'.  */
 370 extern int execl __P ((__const char *__path, __const char *__arg, ...));
 371
 372 /* Execute FILE, searching in the `PATH' environment variable if it contains
 373    no slashes, with arguments ARGV and environment from `environ'.  */
 374 extern int execvp __P ((__const char *__file, char *__const __argv[]));
 375
 376 /* Execute FILE, searching in the `PATH' environment variable if
 377    it contains no slashes, with all arguments after FILE until a
 378    NULL pointer and environment from `environ'.  */
 379 extern int execlp __P ((__const char *__file, __const char *__arg, ...));
 380
 381
 382 #if defined __USE_MISC || defined __USE_XOPEN
 383 /* Add INC to priority of the current process.  */
 384 extern int nice __P ((int __inc));
 385 #endif
 386
 387
 388 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 389 extern void _exit __P ((int __status)) __attribute__ ((__noreturn__));
 390
 391
 392 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 393    the `_SC_*' symbols for the NAME argument to `sysconf';
 394    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 395 #include <bits/confname.h>
 396
 397 /* Get file-specific configuration information about PATH.  */
 398 extern long int __pathconf __P ((__const char *__path, int __name));
 399 extern long int pathconf __P ((__const char *__path, int __name));
 400
 401 /* Get file-specific configuration about descriptor FD.  */
 402 extern long int __fpathconf __P ((int __fd, int __name));
 403 extern long int fpathconf __P ((int __fd, int __name));
 404
 405 /* Get the value of the system variable NAME.  */
 406 extern long int __sysconf __P ((int __name));
 407 extern long int sysconf __P ((int __name));
 408
 409 #ifdef  __USE_POSIX2
 410 /* Get the value of the string-valued system variable NAME.  */
 411 extern size_t confstr __P ((int __name, char *__buf, size_t __len));
 412 #endif
 413
 414
 415 /* Get the process ID of the calling process.  */
 416 extern __pid_t __getpid __P ((void));
 417 extern __pid_t getpid __P ((void));
 418
 419 /* Get the process ID of the calling process's parent.  */
 420 extern __pid_t __getppid __P ((void));
 421 extern __pid_t getppid __P ((void));
 422
 423 /* Get the process group ID of the calling process.  */
 424 extern __pid_t getpgrp __P ((void));
 425 /* The old BSD definition is a bit different.  */
 426 extern __pid_t __bsd_getpgrp __P ((__pid_t __pid));
 427 #ifdef __FAVOR_BSD
 428 /* When we explicitely compile BSD sources use the BSD definition of this
 429    function.  Please note that we cannot use parameters for the macro.  */
 430 #define getpgrp __bsd_getpgrp
 431 #endif
 432
 433 /* Set the process group ID of the process matching PID to PGID.
 434    If PID is zero, the current process's process group ID is set.
 435    If PGID is zero, the process ID of the process is used.  */
 436 extern int setpgid __P ((__pid_t __pid, __pid_t __pgid));
 437
 438 /* Get the process group ID of process PID.  */
 439 extern __pid_t __getpgid __P ((__pid_t __pid));
 440 #ifdef __USE_XOPEN_EXTENDED
 441 extern __pid_t getpgid __P ((__pid_t __pid));
 442 #endif
 443
 444 #if defined __USE_SVID || defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 445 /* Both System V and BSD have `setpgrp' functions, but with different
 446    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 447    (above).  The System V function takes no arguments and puts the calling
 448    process in its on group like `setpgid (0, 0)'.
 449
 450    New programs should always use `setpgid' instead.
 451
 452    The default in GNU is to provide the System V function.  The BSD
 453    function is available under -D_BSD_SOURCE with -lbsd-compat.  */
 454
 455 #ifndef __FAVOR_BSD
 456
 457 /* Set the process group ID of the calling process to its own PID.
 458    This is exactly the same as `setpgid (0, 0)'.  */
 459 extern int setpgrp __P ((void));
 460
 461 #else
 462
 463 /* Another name for `setpgid' (above).  */
 464 extern int setpgrp __P ((__pid_t __pid, __pid_t __pgrp));
 465
 466 #endif  /* Favor BSD.  */
 467 #endif  /* Use SVID or BSD.  */
 468
 469 /* Create a new session with the calling process as its leader.
 470    The process group IDs of the session and the calling process
 471    are set to the process ID of the calling process, which is returned.  */
 472 extern __pid_t __setsid __P ((void));
 473 extern __pid_t setsid __P ((void));
 474
 475 #ifdef __USE_XOPEN_EXTENDED
 476 /* Return the session ID of the given process.  */
 477 extern __pid_t getsid __P ((__pid_t __pid));
 478 #endif
 479
 480 /* Get the real user ID of the calling process.  */
 481 extern __uid_t __getuid __P ((void));
 482 extern __uid_t getuid __P ((void));
 483
 484 /* Get the effective user ID of the calling process.  */
 485 extern __uid_t __geteuid __P ((void));
 486 extern __uid_t geteuid __P ((void));
 487
 488 /* Get the real group ID of the calling process.  */
 489 extern __gid_t __getgid __P ((void));
 490 extern __gid_t getgid __P ((void));
 491
 492 /* Get the effective group ID of the calling process.  */
 493 extern __gid_t __getegid __P ((void));
 494 extern __gid_t getegid __P ((void));
 495
 496 /* If SIZE is zero, return the number of supplementary groups
 497    the calling process is in.  Otherwise, fill in the group IDs
 498    of its supplementary groups in LIST and return the number written.  */
 499 extern int __getgroups __P ((int __size, __gid_t __list[]));
 500 extern int getgroups __P ((int __size, __gid_t __list[]));
 501
 502 #ifdef  __USE_GNU
 503 /* Return nonzero iff the calling process is in group GID.  */
 504 extern int __group_member __P ((__gid_t __gid));
 505 extern int group_member __P ((__gid_t __gid));
 506 #endif
 507
 508 /* Set the user ID of the calling process to UID.
 509    If the calling process is the super-user, set the real
 510    and effective user IDs, and the saved set-user-ID to UID;
 511    if not, the effective user ID is set to UID.  */
 512 extern int __setuid __P ((__uid_t __uid));
 513 extern int setuid __P ((__uid_t __uid));
 514
 515 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 516 /* Set the real user ID of the calling process to RUID,
 517    and the effective user ID of the calling process to EUID.  */
 518 extern int __setreuid __P ((__uid_t __ruid, __uid_t __euid));
 519 extern int setreuid __P ((__uid_t __ruid, __uid_t __euid));
 520 #endif
 521
 522 #ifdef  __USE_BSD
 523 /* Set the effective user ID of the calling process to UID.  */
 524 extern int seteuid __P ((__uid_t __uid));
 525 #endif /* Use BSD.  */
 526
 527 /* Set the group ID of the calling process to GID.
 528    If the calling process is the super-user, set the real
 529    and effective group IDs, and the saved set-group-ID to GID;
 530    if not, the effective group ID is set to GID.  */
 531 extern int __setgid __P ((__gid_t __gid));
 532 extern int setgid __P ((__gid_t __gid));
 533
 534 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 535 /* Set the real group ID of the calling process to RGID,
 536    and the effective group ID of the calling process to EGID.  */
 537 extern int __setregid __P ((__gid_t __rgid, __gid_t __egid));
 538 extern int setregid __P ((__gid_t __rgid, __gid_t __egid));
 539 #endif
 540
 541 #ifdef __USE_BSD
 542 /* Set the effective group ID of the calling process to GID.  */
 543 extern int setegid __P ((__gid_t __gid));
 544 #endif /* Use BSD.  */
 545
 546
 547 /* Clone the calling process, creating an exact copy.
 548    Return -1 for errors, 0 to the new process,
 549    and the process ID of the new process to the old process.  */
 550 extern __pid_t __fork __P ((void));
 551 extern __pid_t fork __P ((void));
 552
 553 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 554 /* Clone the calling process, but without copying the whole address space.
 555    The the calling process is suspended until the the new process exits or is
 556    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 557    and the process ID of the new process to the old process.  */
 558 extern __pid_t __vfork __P ((void));
 559 extern __pid_t vfork __P ((void));
 560 #endif /* Use BSD. */
 561
 562
 563 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 564    The returned storage is good only until the next call to this function.  */
 565 extern char *ttyname __P ((int __fd));
 566
 567 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 568    open on in BUF.  Return 0 on success, -1 otherwise.  */
 569 extern int __ttyname_r __P ((int __fd, char *__buf, size_t __buflen));
 570 extern int ttyname_r __P ((int __fd, char *__buf, size_t __buflen));
 571
 572 /* Return 1 if FD is a valid descriptor associated
 573    with a terminal, zero if not.  */
 574 extern int __isatty __P ((int __fd));
 575 extern int isatty __P ((int __fd));
 576
 577 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 578 /* Return the index into the active-logins file (utmp) for
 579    the controlling terminal.  */
 580 extern int ttyslot __P ((void));
 581 #endif
 582
 583
 584 /* Make a link to FROM named TO.  */
 585 extern int __link __P ((__const char *__from, __const char *__to));
 586 extern int link __P ((__const char *__from, __const char *__to));
 587
 588 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 589 /* Make a symbolic link to FROM named TO.  */
 590 extern int __symlink __P ((__const char *__from, __const char *__to));
 591 extern int symlink __P ((__const char *__from, __const char *__to));
 592
 593 /* Read the contents of the symbolic link PATH into no more than
 594    LEN bytes of BUF.  The contents are not null-terminated.
 595    Returns the number of characters read, or -1 for errors.  */
 596 extern int __readlink __P ((__const char *__path, char *__buf, size_t __len));
 597 extern int readlink __P ((__const char *__path, char *__buf, size_t __len));
 598 #endif /* Use BSD.  */
 599
 600 /* Remove the link NAME.  */
 601 extern int __unlink __P ((__const char *__name));
 602 extern int unlink __P ((__const char *__name));
 603
 604 /* Remove the directory PATH.  */
 605 extern int __rmdir __P ((__const char *__path));
 606 extern int rmdir __P ((__const char *__path));
 607
 608
 609 /* Return the foreground process group ID of FD.  */
 610 extern __pid_t tcgetpgrp __P ((int __fd));
 611
 612 /* Set the foreground process group ID of FD set PGRP_ID.  */
 613 extern int tcsetpgrp __P ((int __fd, __pid_t __pgrp_id));
 614
 615
 616 /* Return the login name of the user.  */
 617 extern char *getlogin __P ((void));
 618 #ifdef __USE_REENTRANT
 619 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 620    If it cannot be determined or some other error occurred, return the error
 621    code.  Otherwise return 0.  */
 622 extern int getlogin_r __P ((char *__name, size_t __name_len));
 623 #endif
 624
 625 #ifdef  __USE_BSD
 626 /* Set the login name returned by `getlogin'.  */
 627 extern int setlogin __P ((__const char *__name));
 628 #endif
 629
 630
 631 #ifdef  __USE_POSIX2
 632 /* Process the arguments in ARGV (ARGC of them, minus
 633    the program name) for options given in OPTS.
 634
 635    If `opterr' is zero, no messages are generated
 636    for invalid options; it defaults to 1.
 637    `optind' is the current index into ARGV.
 638    `optarg' is the argument corresponding to the current option.
 639    Return the option character from OPTS just read.
 640    Return -1 when there are no more options.
 641    For unrecognized options, or options missing arguments,
 642    `optopt' is set to the option letter, and '?' is returned.
 643
 644    The OPTS string is a list of characters which are recognized option
 645    letters, optionally followed by colons, specifying that that letter
 646    takes an argument, to be placed in `optarg'.
 647
 648    If a letter in OPTS is followed by two colons, its argument is optional.
 649    This behavior is specific to the GNU `getopt'.
 650
 651    The argument `--' causes premature termination of argument scanning,
 652    explicitly telling `getopt' that there are no more options.
 653
 654    If OPTS begins with `--', then non-option arguments
 655    are treated as arguments to the option '\0'.
 656    This behavior is specific to the GNU `getopt'.  */
 657 extern int getopt __P ((int __argc, char *__const * __argv,
 658                         __const char *__opts));
 659 extern int opterr;
 660 extern int optind;
 661 extern int optopt;
 662 extern char *optarg;
 663 #endif
 664
 665
 666 #if defined __USE_BSD || defined __USE_XOPEN
 667
 668 /* Put the name of the current host in no more than LEN bytes of NAME.
 669    The result is null-terminated if LEN is large enough for the full
 670    name and the terminator.  */
 671 extern int __gethostname __P ((char *__name, size_t __len));
 672 extern int gethostname __P ((char *__name, size_t __len));
 673
 674 /* Set the name of the current host to NAME, which is LEN bytes long.
 675    This call is restricted to the super-user.  */
 676 extern int sethostname __P ((__const char *__name, size_t __len));
 677
 678 /* Set the current machine's Internet number to ID.
 679    This call is restricted to the super-user.  */
 680 extern int sethostid __P ((long int __id));
 681
 682
 683 /* Get and set the NIS (aka YP) domain name, if any.
 684    Called just like `gethostname' and `sethostname'.
 685    The NIS domain name is usually the empty string when not using NIS.  */
 686 extern int getdomainname __P ((char *__name, size_t __len));
 687 extern int setdomainname __P ((__const char *__name, size_t __len));
 688
 689
 690 /* Make all changes done to FD actually appear on disk.  */
 691 extern int fsync __P ((int __fd));
 692
 693
 694 /* Revoke access permissions to all processes currently communicating
 695    with the control terminal, and then send a SIGHUP signal to the process
 696    group of the control terminal.  */
 697 extern int vhangup __P ((void));
 698
 699 /* Revoke the access of all descriptors currently open on FILE.  */
 700 extern int revoke __P ((__const char *__file));
 701
 702
 703 /* Enable statistical profiling, writing samples of the PC into at most
 704    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 705    is enabled, the system examines the user PC and increments
 706    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 707    disable profiling.  Returns zero on success, -1 on error.  */
 708 extern int profil __P ((unsigned short int *__sample_buffer, size_t __size,
 709                         size_t __offset, unsigned int __scale));
 710
 711
 712 /* Turn accounting on if NAME is an existing file.  The system will then write
 713    a record for each process as it terminates, to this file.  If NAME is NULL,
 714    turn accounting off.  This call is restricted to the super-user.  */
 715 extern int acct __P ((__const char *__name));
 716
 717 /* Make PATH be the root directory (the starting point for absolute paths).
 718    This call is restricted to the super-user.  */
 719 extern int chroot __P ((__const char *__path));
 720
 721
 722 /* Successive calls return the shells listed in `/etc/shells'.  */
 723 extern char *getusershell __P ((void));
 724 extern void endusershell __P ((void)); /* Discard cached info.  */
 725 extern void setusershell __P ((void)); /* Rewind and re-read the file.  */
 726
 727
 728 /* Prompt with PROMPT and read a string from the terminal without echoing.
 729    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 730 extern char *getpass __P ((__const char *__prompt));
 731
 732 /* Put the program in the background, and dissociate from the controlling
 733    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 734    redirects stdin, stdout, and stderr to /dev/null.  */
 735 extern int daemon __P ((int __nochdir, int __noclose));
 736
 737 #endif /* Use BSD || X/Open.  */
 738
 739
 740 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 741
 742 /* Return the current machine's Internet number.  */
 743 extern long int gethostid __P ((void));
 744
 745 /* Make all changes done to all files actually appear on disk.  */
 746 extern int sync __P ((void));
 747
 748
 749 /* Return the number of bytes in a page.  This is the system's page size,
 750    which is not necessarily the same as the hardware page size.  */
 751 extern int __getpagesize __P ((void));
 752 extern int getpagesize __P ((void));
 753
 754
 755 /* Truncate FILE to LENGTH bytes.  */
 756 extern int truncate __P ((__const char *__file, __off_t __length));
 757
 758 /* Truncate the file FD is open on to LENGTH bytes.  */
 759 extern int ftruncate __P ((int __fd, __off_t __length));
 760
 761
 762 /* Return the maximum number of file descriptors
 763    the current process could possibly have.  */
 764 extern int __getdtablesize __P ((void));
 765 extern int getdtablesize __P ((void));
 766
 767 #endif /* Use BSD || X/Open Unix.  */
 768
 769
 770 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 771
 772 /* Set the end of accessible data space (aka "the break") to ADDR.
 773    Returns zero on success and -1 for errors (with errno set).  */
 774 extern int __brk __P ((__ptr_t __addr));
 775 extern int brk __P ((__ptr_t __addr));
 776
 777 #define __need_ptrdiff_t
 778 #include <stddef.h>
 779
 780 /* Increase or decrease the end of accessible data space by DELTA bytes.
 781    If successful, returns the address the previous end of data space
 782    (i.e. the beginning of the new space, if DELTA > 0);
 783    returns (void *) -1 for errors (with errno set).  */
 784 extern __ptr_t __sbrk __P ((ptrdiff_t __delta));
 785 extern __ptr_t sbrk __P ((ptrdiff_t __delta));
 786 #endif
 787
 788
 789 #ifdef __USE_MISC
 790 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 791    This is completely system-dependent, and not often useful.
 792
 793    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 794    for errors; in many systems you cannot pass arguments or get return
 795    values for all system calls (`pipe', `fork', and `getppid' typically
 796    among them).
 797
 798    In Mach, all system calls take normal arguments and always return an
 799    error code (zero for success).  */
 800 extern long int syscall __P ((long int __sysno, ...));
 801
 802 #endif  /* Use misc.  */
 803
 804
 805 #if (defined __USE_MISC || defined __USE_XOPEN_EXTENDED) && !defined F_LOCK
 806 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
 807    files consistent.  Some systems have them there and some here, and some
 808    software depends on the macros being defined without including both.  */
 809
 810 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 811    LEN is always relative to the current file position.
 812    The CMD argument is one of the following.  */
 813
 814 #define F_ULOCK 0       /* Unlock a previously locked region.  */
 815 #define F_LOCK  1       /* Lock a region for exclusive use.  */
 816 #define F_TLOCK 2       /* Test and lock a region for exclusive use.  */
 817 #define F_TEST  3       /* Test a region for other processes locks.  */
 818
 819 extern int lockf __P ((int __fd, int __cmd, __off_t __len));
 820 #endif /* Use misc and F_LOCK not already defined.  */
 821
 822
 823 #ifdef __USE_GNU
 824
 825 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
 826    set to EINTR.  */
 827
 828 #define TEMP_FAILURE_RETRY(expression) \
 829   (__extension__                                                              \
 830     ({ long int __result;                                                     \
 831        do __result = (long int) (expression);                                 \
 832        while (__result == -1L && errno == EINTR);                             \
 833        __result; }))                                                          \
 834
 835
 836 /* This variable is set nonzero at startup if the process's effective IDs
 837    differ from its real IDs, or it is otherwise indicated that extra
 838    security should be used.  When this is set the dynamic linker ignores
 839    the various environment variables that normally affect it.  */
 840 extern int __libc_enable_secure;
 841
 842 #endif
 843
 844 #ifdef __USE_POSIX199309
 845 /* Synchronize at least the data part of a file with the underlying
 846    media.  */
 847 extern int fdatasync __P ((int __fildes));
 848 #endif /* Use POSIX199309 */
 849
 850
 851 /* XPG4.2 specifies that prototypes for the encryption functions must
 852    be defined here.  */
 853 #ifdef  __USE_XOPEN
 854 /* Encrypt at most 8 characters from KEY using salt to perturb DES.  */
 855 extern char *crypt __P ((__const char *__key, __const char *__salt));
 856
 857 /* Setup DES tables according KEY.  */
 858 extern void setkey __P ((__const char *__key));
 859
 860 /* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt
 861    block in place.  */
 862 extern void encrypt __P ((char *__block, int __edflag));
 863
 864
 865 /* Swab pairs bytes in the first N bytes of the area pointed to by
 866    FROM and copy the result to TO.  The value of TO must not be in the
 867    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
 868    is without partner.  */
 869 extern void swab __P ((__const char *__from, char *__to, ssize_t __n));
 870 #endif
 871
 872 __END_DECLS
 873
 874 #endif /* unistd.h  */