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
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, 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
  59 /* Get values of POSIX options:
  60
  61    If these symbols are defined, the corresponding features are
  62    always available.  If not, they may be available sometimes.
  63    The current values can be obtained with `sysconf'.
  64
  65    _POSIX_JOB_CONTROL           Job control is supported.
  66    _POSIX_SAVED_IDS             Processes have a saved set-user-ID
  67                                 and a saved set-group-ID.
  68    _POSIX_REALTIME_SIGNALS      Real-time, queued signals are supported.
  69    _POSIX_PRIORITY_SCHEDULING   Priority scheduling is supported.
  70    _POSIX_TIMERS                POSIX.4 clocks and timers are supported.
  71    _POSIX_ASYNCHRONOUS_IO       Asynchronous I/O is supported.
  72    _POSIX_PRIORITIZED_IO        Prioritized asynchronous I/O is supported.
  73    _POSIX_SYNCHRONIZED_IO       Synchronizing file data is supported.
  74    _POSIX_FSYNC                 The fsync function is present.
  75    _POSIX_MAPPED_FILES          Mapping of files to memory is supported.
  76    _POSIX_MEMLOCK               Locking of all memory is supported.
  77    _POSIX_MEMLOCK_RANGE         Locking of ranges of memory is supported.
  78    _POSIX_MEMORY_PROTECTION     Setting of memory protections is supported.
  79    _POSIX_MESSAGE_PASSING       POSIX.4 message queues are supported.
  80    _POSIX_SEMAPHORES            POSIX.4 counting semaphores are supported.
  81    _POSIX_SHARED_MEMORY_OBJECTS POSIX.4 shared memory objects are supported.
  82    _POSIX_PII                   Protocol-independent interfaces are supported.
  83    _POSIX_PII_XTI               XTI protocol-indep. interfaces are supported.
  84    _POSIX_PII_SOCKET            Socket protocol-indep. interfaces are supported.
  85    _POSIX_PII_INTERNET          Internet family of protocols supported.
  86    _POSIX_PII_INTERNET_STREAM   Connection-mode Internet protocol supported.
  87    _POSIX_PII_INTERNET_DGRAM    Connectionless Internet protocol supported.
  88    _POSIX_PII_OSI               ISO/OSI family of protocols supported.
  89    _POSIX_PII_OSI_COTS          Connection-mode ISO/OSI service supported.
  90    _POSIX_PII_OSI_CLTS          Connectionless ISO/OSI service supported.
  91    _POSIX_POLL                  Implementation supports `poll' function.
  92    _POSIX_SELECT                Implementation supports `select' and `pselect'.
  93
  94    If any of these symbols is defined as -1, the corresponding option is not
  95    true for any file.  If any is defined as other than -1, the corresponding
  96    option is true for all files.  If a symbol is not defined at all, the value
  97    for a specific file can be obtained from `pathconf' and `fpathconf'.
  98
  99    _POSIX_CHOWN_RESTRICTED      Only the super user can use `chown' to change
 100                                 the owner of a file.  `chown' can only be used
 101                                 to change the group ID of a file to a group of
 102                                 which the calling process is a member.
 103    _POSIX_NO_TRUNC              Pathname components longer than
 104                                 NAME_MAX generate an error.
 105    _POSIX_VDISABLE              If defined, if the value of an element of the
 106                                 `c_cc' member of `struct termios' is
 107                                 _POSIX_VDISABLE, no character will have the
 108                                 effect associated with that element.
 109    _POSIX_SYNC_IO               Synchronous I/O may be performed.
 110    _POSIX_ASYNC_IO              Asynchronous I/O may be performed.
 111    _POSIX_PRIO_IO               Prioritized Asynchronous I/O may be performed.
 112    */
 113
 114 #include <posix_opt.h>
 115
 116
 117 /* Standard file descriptors.  */
 118 #define STDIN_FILENO    0       /* Standard input.  */
 119 #define STDOUT_FILENO   1       /* Standard output.  */
 120 #define STDERR_FILENO   2       /* Standard error output.  */
 121
 122
 123 /* All functions that are not declared anywhere else.  */
 124
 125 #include <gnu/types.h>
 126
 127 #ifndef ssize_t
 128 #define ssize_t __ssize_t
 129 #endif
 130
 131 #define __need_size_t
 132 #define __need_NULL
 133 #include <stddef.h>
 134
 135
 136 /* Values for the second argument to access.
 137    These may be OR'd together.  */
 138 #define R_OK    4               /* Test for read permission.  */
 139 #define W_OK    2               /* Test for write permission.  */
 140 #define X_OK    1               /* Test for execute permission.  */
 141 #define F_OK    0               /* Test for existence.  */
 142
 143 /* Test for access to NAME using the real UID and real GID.  */
 144 extern int __access __P ((__const char *__name, int __type));
 145 extern int access __P ((__const char *__name, int __type));
 146
 147 #ifdef __USE_GNU
 148 /* Test for access to NAME using the effective UID and GID
 149    (as normal file operations use).  */
 150 extern int euidaccess __P ((__const char *__name, int __type));
 151 #endif
 152
 153
 154 /* Values for the WHENCE argument to lseek.  */
 155 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 156 #define SEEK_SET        0       /* Seek from beginning of file.  */
 157 #define SEEK_CUR        1       /* Seek from current position.  */
 158 #define SEEK_END        2       /* Seek from end of file.  */
 159 #endif
 160
 161 #if defined (__USE_BSD) && !defined (L_SET)
 162 /* Old BSD names for the same constants; just for compatibility.  */
 163 #define L_SET           SEEK_SET
 164 #define L_INCR          SEEK_CUR
 165 #define L_XTND          SEEK_END
 166 #endif
 167
 168
 169 /* Move FD's file position to OFFSET bytes from the
 170    beginning of the file (if WHENCE is SEEK_SET),
 171    the current position (if WHENCE is SEEK_CUR),
 172    or the end of the file (if WHENCE is SEEK_END).
 173    Return the new file position.  */
 174 extern __off_t __lseek __P ((int __fd, __off_t __offset, int __whence));
 175 extern __off_t lseek __P ((int __fd, __off_t __offset, int __whence));
 176
 177 /* Close the file descriptor FD.  */
 178 extern int __close __P ((int __fd));
 179 extern int close __P ((int __fd));
 180
 181 /* Read NBYTES into BUF from FD.  Return the
 182    number read, -1 for errors or 0 for EOF.  */
 183 extern ssize_t __read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 184 extern ssize_t read __P ((int __fd, __ptr_t __buf, size_t __nbytes));
 185
 186 /* Write N bytes of BUF to FD.  Return the number written, or -1.  */
 187 extern ssize_t __write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 188 extern ssize_t write __P ((int __fd, __const __ptr_t __buf, size_t __n));
 189
 190
 191 /* Create a one-way communication channel (pipe).
 192    If successul, two file descriptors are stored in PIPEDES;
 193    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 194    Returns 0 if successful, -1 if not.  */
 195 extern int __pipe __P ((int __pipedes[2]));
 196 extern int pipe __P ((int __pipedes[2]));
 197
 198 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 199    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 200    The function returns the number of seconds remaining until the last
 201    alarm scheduled would have signaled, or zero if there wasn't one.
 202    There is no return value to indicate an error, but you can set `errno'
 203    to 0 and check its value after calling `alarm', and this might tell you.
 204    The signal may come late due to processor scheduling.  */
 205 extern unsigned int alarm __P ((unsigned int __seconds));
 206
 207 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 208    and is not ignored.  The function returns the number of seconds less
 209    than SECONDS which it actually slept (thus zero if it slept the full time).
 210    If a signal handler does a `longjmp' or modifies the handling of the
 211    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 212    signal afterwards is undefined.  There is no return value to indicate
 213    error, but if `sleep' returns SECONDS, it probably didn't work.  */
 214 extern unsigned int sleep __P ((unsigned int __seconds));
 215
 216 #ifdef __USE_BSD
 217 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 218    or ignored.  Return value is not necessarily useful.  */
 219 extern unsigned int usleep __P ((unsigned int __useconds));
 220 #endif
 221
 222
 223 /* Suspend the process until a signal arrives.
 224    This always returns -1 and sets `errno' to EINTR.  */
 225 extern int pause __P ((void));
 226
 227
 228 /* Change the owner and group of FILE.  */
 229 extern int __chown __P ((__const char *__file,
 230                          __uid_t __owner, __gid_t __group));
 231 extern int chown __P ((__const char *__file,
 232                        __uid_t __owner, __gid_t __group));
 233
 234 #ifdef  __USE_BSD
 235 /* Change the owner and group of the file that FD is open on.  */
 236 extern int __fchown __P ((int __fd,
 237                           __uid_t __owner, __gid_t __group));
 238 extern int fchown __P ((int __fd,
 239                         __uid_t __owner, __gid_t __group));
 240 #endif /* Use BSD.  */
 241
 242 /* Change the process's working directory to PATH.  */
 243 extern int __chdir __P ((__const char *__path));
 244 extern int chdir __P ((__const char *__path));
 245
 246 #ifdef __USE_BSD
 247 /* Change the process's working directory to the one FD is open on.  */
 248 extern int fchdir __P ((int __fd));
 249 #endif
 250
 251 /* Get the pathname of the current working directory,
 252    and put it in SIZE bytes of BUF.  Returns NULL if the
 253    directory couldn't be determined or SIZE was too small.
 254    If successful, returns BUF.  In GNU, if BUF is NULL,
 255    an array is allocated with `malloc'; the array is SIZE
 256    bytes long, unless SIZE <= 0, in which case it is as
 257    big as necessary.  */
 258 extern char *__getcwd __P ((char *__buf, size_t __size));
 259 extern char *getcwd __P ((char *__buf, size_t __size));
 260
 261 #ifdef  __USE_GNU
 262 /* Return a malloc'd string containing the current directory name.
 263    If the environment variable `PWD' is set, and its value is correct,
 264    that value is used.  */
 265 extern char *get_current_dir_name __P ((void));
 266
 267 /* Get the canonical absolute name of the named directory, and put it in SIZE
 268    bytes of BUF.  Returns NULL if the directory couldn't be determined or
 269    SIZE was too small.  If successful, returns BUF.  In GNU, if BUF is
 270    NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
 271    unless SIZE <= 0, in which case it is as big as necessary.  */
 272
 273 char *__canonicalize_directory_name_internal __P ((__const char *__thisdir,
 274                                                    char *__buf,
 275                                                    size_t __size));
 276 #endif
 277
 278 #ifdef  __USE_BSD
 279 /* Put the absolute pathname of the current working directory in BUF.
 280    If successful, return BUF.  If not, put an error message in
 281    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 282 extern char *getwd __P ((char *__buf));
 283 #endif
 284
 285
 286 /* Duplicate FD, returning a new file descriptor on the same file.  */
 287 extern int __dup __P ((int __fd));
 288 extern int dup __P ((int __fd));
 289
 290 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 291 extern int __dup2 __P ((int __fd, int __fd2));
 292 extern int dup2 __P ((int __fd, int __fd2));
 293
 294 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 295 extern char **__environ;
 296 extern char **environ;
 297
 298
 299 /* Replace the current process, executing PATH with arguments ARGV and
 300    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 301 extern int __execve __P ((__const char *__path, char *__const __argv[],
 302                           char *__const __envp[]));
 303 extern int execve __P ((__const char *__path, char *__const __argv[],
 304                         char *__const __envp[]));
 305
 306 #ifdef __USE_GNU
 307 /* Execute the file FD refers to, overlaying the running program image.
 308    ARGV and ENVP are passed to the new program, as for `execve'.  */
 309 extern int fexecve __P ((int __fd,
 310                          char *__const __argv[], char *__const __envp[]));
 311
 312 #endif
 313
 314
 315 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 316 extern int execv __P ((__const char *__path, char *__const __argv[]));
 317
 318 /* Execute PATH with all arguments after PATH until a NULL pointer,
 319    and the argument after that for environment.  */
 320 extern int execle __P ((__const char *__path, __const char *__arg, ...));
 321
 322 /* Execute PATH with all arguments after PATH until
 323    a NULL pointer and environment from `environ'.  */
 324 extern int execl __P ((__const char *__path, __const char *__arg, ...));
 325
 326 /* Execute FILE, searching in the `PATH' environment variable if it contains
 327    no slashes, with arguments ARGV and environment from `environ'.  */
 328 extern int execvp __P ((__const char *__file, char *__const __argv[]));
 329
 330 /* Execute FILE, searching in the `PATH' environment variable if
 331    it contains no slashes, with all arguments after FILE until a
 332    NULL pointer and environment from `environ'.  */
 333 extern int execlp __P ((__const char *__file, ...));
 334
 335
 336 #ifdef __USE_MISC
 337 /* Add INC to priority of the current process.  */
 338 extern int nice __P ((int __inc));
 339 #endif
 340
 341
 342 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 343 extern void _exit __P ((int __status)) __attribute__ ((__noreturn__));
 344
 345
 346 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 347    the `_SC_*' symbols for the NAME argument to `sysconf';
 348    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 349 #include <confname.h>
 350
 351 /* Get file-specific configuration information about PATH.  */
 352 extern long int __pathconf __P ((__const char *__path, int __name));
 353 extern long int pathconf __P ((__const char *__path, int __name));
 354
 355 /* Get file-specific configuration about descriptor FD.  */
 356 extern long int __fpathconf __P ((int __fd, int __name));
 357 extern long int fpathconf __P ((int __fd, int __name));
 358
 359 /* Get the value of the system variable NAME.  */
 360 extern long int __sysconf __P ((int __name));
 361 extern long int sysconf __P ((int __name));
 362
 363 #ifdef  __USE_POSIX2
 364 /* Get the value of the string-valued system variable NAME.  */
 365 extern size_t confstr __P ((int __name, char *__buf, size_t __len));
 366 #endif
 367
 368
 369 /* Get the process ID of the calling process.  */
 370 extern __pid_t __getpid __P ((void));
 371 extern __pid_t getpid __P ((void));
 372
 373 /* Get the process ID of the calling process's parent.  */
 374 extern __pid_t __getppid __P ((void));
 375 extern __pid_t getppid __P ((void));
 376
 377 /* Get the process group ID of the calling process.  */
 378 extern __pid_t getpgrp __P ((void));
 379
 380 /* Set the process group ID of the process matching PID to PGID.
 381    If PID is zero, the current process's process group ID is set.
 382    If PGID is zero, the process ID of the process is used.  */
 383 extern int setpgid __P ((__pid_t __pid, __pid_t __pgid));
 384
 385 /* Get the process group ID of process PID.  */
 386 extern __pid_t __getpgid __P ((__pid_t __pid));
 387 #ifdef __USE_GNU
 388 extern __pid_t getpgid __P ((__pid_t __pid));
 389 #endif
 390
 391 #if defined (__USE_SVID) || defined (__USE_BSD)
 392 /* Both System V and BSD have `setpgrp' functions, but with different
 393    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 394    (above).  The System V function takes no arguments and puts the calling
 395    process in its on group like `setpgid (0, 0)'.
 396
 397    New programs should always use `setpgid' instead.
 398
 399    The default in GNU is to provide the System V function.  The BSD
 400    function is available under -D_BSD_SOURCE with -lbsd-compat.  */
 401
 402 #ifndef __FAVOR_BSD
 403
 404 /* Set the process group ID of the calling process to its own PID.
 405    This is exactly the same as `setpgid (0, 0)'.  */
 406 extern int setpgrp __P ((void));
 407
 408 #else
 409
 410 /* Another name for `setpgid' (above).  */
 411 extern int setpgrp __P ((__pid_t __pid, __pid_t __pgrp));
 412
 413 #endif  /* Favor BSD.  */
 414 #endif  /* Use SVID or BSD.  */
 415
 416 /* Create a new session with the calling process as its leader.
 417    The process group IDs of the session and the calling process
 418    are set to the process ID of the calling process, which is returned.  */
 419 extern __pid_t __setsid __P ((void));
 420 extern __pid_t setsid __P ((void));
 421
 422 #ifdef __USE_GNU
 423 /* Return the session ID of the given process.  */
 424 extern __pid_t getsid __P ((__pid_t __pid));
 425 #endif
 426
 427 /* Get the real user ID of the calling process.  */
 428 extern __uid_t __getuid __P ((void));
 429 extern __uid_t getuid __P ((void));
 430
 431 /* Get the effective user ID of the calling process.  */
 432 extern __uid_t __geteuid __P ((void));
 433 extern __uid_t geteuid __P ((void));
 434
 435 /* Get the real group ID of the calling process.  */
 436 extern __gid_t __getgid __P ((void));
 437 extern __gid_t getgid __P ((void));
 438
 439 /* Get the effective group ID of the calling process.  */
 440 extern __gid_t __getegid __P ((void));
 441 extern __gid_t getegid __P ((void));
 442
 443 /* If SIZE is zero, return the number of supplementary groups
 444    the calling process is in.  Otherwise, fill in the group IDs
 445    of its supplementary groups in LIST and return the number written.  */
 446 extern int __getgroups __P ((int __size, __gid_t __list[]));
 447 extern int getgroups __P ((int __size, __gid_t __list[]));
 448
 449 #ifdef  __USE_GNU
 450 /* Return nonzero iff the calling process is in group GID.  */
 451 extern int __group_member __P ((__gid_t __gid));
 452 extern int group_member __P ((__gid_t __gid));
 453 #endif
 454
 455 /* Set the user ID of the calling process to UID.
 456    If the calling process is the super-user, set the real
 457    and effective user IDs, and the saved set-user-ID to UID;
 458    if not, the effective user ID is set to UID.  */
 459 extern int __setuid __P ((__uid_t __uid));
 460 extern int setuid __P ((__uid_t __uid));
 461
 462 #ifdef  __USE_BSD
 463 /* Set the real user ID of the calling process to RUID,
 464    and the effective user ID of the calling process to EUID.  */
 465 extern int __setreuid __P ((__uid_t __ruid, __uid_t __euid));
 466 extern int setreuid __P ((__uid_t __ruid, __uid_t __euid));
 467
 468 /* Set the effective user ID of the calling process to UID.  */
 469 extern int seteuid __P ((__uid_t __uid));
 470 #endif /* Use BSD.  */
 471
 472 /* Set the group ID of the calling process to GID.
 473    If the calling process is the super-user, set the real
 474    and effective group IDs, and the saved set-group-ID to GID;
 475    if not, the effective group ID is set to GID.  */
 476 extern int __setgid __P ((__gid_t __gid));
 477 extern int setgid __P ((__gid_t __gid));
 478
 479 #ifdef  __USE_BSD
 480 /* Set the real group ID of the calling process to RGID,
 481    and the effective group ID of the calling process to EGID.  */
 482 extern int __setregid __P ((__gid_t __rgid, __gid_t __egid));
 483 extern int setregid __P ((__gid_t __rgid, __gid_t __egid));
 484
 485 /* Set the effective group ID of the calling process to GID.  */
 486 extern int setegid __P ((__gid_t __gid));
 487 #endif /* Use BSD.  */
 488
 489
 490 /* Clone the calling process, creating an exact copy.
 491    Return -1 for errors, 0 to the new process,
 492    and the process ID of the new process to the old process.  */
 493 extern __pid_t __fork __P ((void));
 494 extern __pid_t fork __P ((void));
 495
 496 #ifdef  __USE_BSD
 497 /* Clone the calling process, but without copying the whole address space.
 498    The the calling process is suspended until the the new process exits or is
 499    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 500    and the process ID of the new process to the old process.  */
 501 extern __pid_t __vfork __P ((void));
 502 extern __pid_t vfork __P ((void));
 503 #endif /* Use BSD. */
 504
 505
 506 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 507    The returned storage is good only until the next call to this function.  */
 508 extern char *ttyname __P ((int __fd));
 509 #ifdef __USE_REENTRANT
 510 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 511    open on in BUF.  Return 0 on success, -1 otherwise.  */
 512 extern int __ttyname_r __P ((int __fd, char *__buf, int __buflen));
 513 extern int ttyname_r __P ((int __fd, char *__buf, int __buflen));
 514 #endif
 515
 516 /* Return 1 if FD is a valid descriptor associated
 517    with a terminal, zero if not.  */
 518 extern int __isatty __P ((int __fd));
 519 extern int isatty __P ((int __fd));
 520
 521 #ifdef __USE_BSD
 522 /* Return the index into the active-logins file (utmp) for
 523    the controlling terminal.  */
 524 extern int ttyslot __P ((void));
 525 #endif
 526
 527
 528 /* Make a link to FROM named TO.  */
 529 extern int __link __P ((__const char *__from, __const char *__to));
 530 extern int link __P ((__const char *__from, __const char *__to));
 531
 532 #ifdef  __USE_BSD
 533 /* Make a symbolic link to FROM named TO.  */
 534 extern int __symlink __P ((__const char *__from, __const char *__to));
 535 extern int symlink __P ((__const char *__from, __const char *__to));
 536
 537 /* Read the contents of the symbolic link PATH into no more than
 538    LEN bytes of BUF.  The contents are not null-terminated.
 539    Returns the number of characters read, or -1 for errors.  */
 540 extern int __readlink __P ((__const char *__path, char *__buf, size_t __len));
 541 extern int readlink __P ((__const char *__path, char *__buf, size_t __len));
 542 #endif /* Use BSD.  */
 543
 544 /* Remove the link NAME.  */
 545 extern int __unlink __P ((__const char *__name));
 546 extern int unlink __P ((__const char *__name));
 547
 548 /* Remove the directory PATH.  */
 549 extern int __rmdir __P ((__const char *__path));
 550 extern int rmdir __P ((__const char *__path));
 551
 552
 553 /* Return the foreground process group ID of FD.  */
 554 extern __pid_t tcgetpgrp __P ((int __fd));
 555
 556 /* Set the foreground process group ID of FD set PGRP_ID.  */
 557 extern int tcsetpgrp __P ((int __fd, __pid_t __pgrp_id));
 558
 559
 560 /* Return the login name of the user.  */
 561 extern char *getlogin __P ((void));
 562 #ifdef __USE_REENTRANT
 563 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 564    If it cannot be determined or some other error occured, return the error
 565    code.  Otherwise return 0.  */
 566 extern int getlogin_r __P ((char *__name, size_t __name_len));
 567 #endif
 568
 569 #ifdef  __USE_BSD
 570 /* Set the login name returned by `getlogin'.  */
 571 extern int setlogin __P ((__const char *__name));
 572 #endif
 573
 574
 575 #ifdef  __USE_POSIX2
 576 /* Process the arguments in ARGV (ARGC of them, minus
 577    the program name) for options given in OPTS.
 578
 579    If `opterr' is zero, no messages are generated
 580    for invalid options; it defaults to 1.
 581    `optind' is the current index into ARGV.
 582    `optarg' is the argument corresponding to the current option.
 583    Return the option character from OPTS just read.
 584    Return -1 when there are no more options.
 585    For unrecognized options, or options missing arguments,
 586    `optopt' is set to the option letter, and '?' is returned.
 587
 588    The OPTS string is a list of characters which are recognized option
 589    letters, optionally followed by colons, specifying that that letter
 590    takes an argument, to be placed in `optarg'.
 591
 592    If a letter in OPTS is followed by two colons, its argument is optional.
 593    This behavior is specific to the GNU `getopt'.
 594
 595    The argument `--' causes premature termination of argument scanning,
 596    explicitly telling `getopt' that there are no more options.
 597
 598    If OPTS begins with `--', then non-option arguments
 599    are treated as arguments to the option '\0'.
 600    This behavior is specific to the GNU `getopt'.  */
 601 extern int getopt __P ((int __argc, char *__const * __argv,
 602                         __const char *__opts));
 603 extern int opterr;
 604 extern int optind;
 605 extern int optopt;
 606 extern char *optarg;
 607 #endif
 608
 609
 610 #ifdef  __USE_BSD
 611
 612 /* Put the name of the current host in no more than LEN bytes of NAME.
 613    The result is null-terminated if LEN is large enough for the full
 614    name and the terminator.  */
 615 extern int __gethostname __P ((char *__name, size_t __len));
 616 extern int gethostname __P ((char *__name, size_t __len));
 617
 618 /* Set the name of the current host to NAME, which is LEN bytes long.
 619    This call is restricted to the super-user.  */
 620 extern int sethostname __P ((__const char *__name, size_t __len));
 621
 622 /* Return the current machine's Internet number.  */
 623 extern long int gethostid __P ((void));
 624
 625 /* Set the current machine's Internet number to ID.
 626    This call is restricted to the super-user.  */
 627 extern int sethostid __P ((long int __id));
 628
 629
 630 /* Get and set the NIS (aka YP) domain name, if any.
 631    Called just like `gethostname' and `sethostname'.
 632    The NIS domain name is usually the empty string when not using NIS.  */
 633 extern int getdomainname __P ((char *__name, size_t __len));
 634 extern int setdomainname __P ((__const char *__name, size_t __len));
 635
 636
 637 /* Return the number of bytes in a page.  This is the system's page size,
 638    which is not necessarily the same as the hardware page size.  */
 639 extern size_t __getpagesize __P ((void));
 640 extern size_t getpagesize __P ((void));
 641
 642
 643 /* Return the maximum number of file descriptors
 644    the current process could possibly have.  */
 645 extern int __getdtablesize __P ((void));
 646 extern int getdtablesize __P ((void));
 647
 648
 649 /* Truncate FILE to LENGTH bytes.  */
 650 extern int truncate __P ((__const char *__file, __off_t __length));
 651
 652 /* Truncate the file FD is open on to LENGTH bytes.  */
 653 extern int ftruncate __P ((int __fd, __off_t __length));
 654
 655
 656 /* Make all changes done to FD actually appear on disk.  */
 657 extern int fsync __P ((int __fd));
 658
 659 /* Make all changes done to all files actually appear on disk.  */
 660 extern int sync __P ((void));
 661
 662
 663 /* Revoke access permissions to all processes currently communicating
 664    with the control terminal, and then send a SIGHUP signal to the process
 665    group of the control terminal.  */
 666 extern int vhangup __P ((void));
 667
 668 /* Revoke the access of all descriptors currently open on FILE.  */
 669 extern int revoke __P ((__const char *__file));
 670
 671
 672 /* Enable statistical profiling, writing samples of the PC into at most
 673    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 674    is enabled, the system examines the user PC and increments
 675    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 676    disable profiling.  Returns zero on success, -1 on error.  */
 677 extern int profil __P ((unsigned short int *__sample_buffer, size_t __size,
 678                         size_t __offset, unsigned int __scale));
 679
 680
 681 /* Turn accounting on if NAME is an existing file.  The system will then write
 682    a record for each process as it terminates, to this file.  If NAME is NULL,
 683    turn accounting off.  This call is restricted to the super-user.  */
 684 extern int acct __P ((__const char *__name));
 685
 686 /* Make PATH be the root directory (the starting point for absolute paths).
 687    This call is restricted to the super-user.  */
 688 extern int chroot __P ((__const char *__path));
 689
 690
 691 /* Successive calls return the shells listed in `/etc/shells'.  */
 692 extern char *getusershell __P ((void));
 693 extern void endusershell __P ((void)); /* Discard cached info.  */
 694 extern void setusershell __P ((void)); /* Rewind and re-read the file.  */
 695
 696
 697 /* Prompt with PROMPT and read a string from the terminal without echoing.
 698    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 699 extern char *getpass __P ((__const char *__prompt));
 700
 701 /* Put the program in the background, and dissociate from the controlling
 702    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 703    redirects stdin, stdout, and stderr to /dev/null.  */
 704 extern int daemon __P ((int __nochdir, int __noclose));
 705
 706 #endif /* Use BSD.  */
 707
 708
 709 #ifdef __USE_MISC
 710
 711 /* Generate a unique temporary file name from TEMPLATE.
 712    The last six characters of TEMPLATE must be "XXXXXX";
 713    they are replaced with a string that makes the file name unique.
 714    Returns TEMPLATE, or a null pointer if it cannot get a unique file name.  */
 715 extern char *mktemp __P ((char *__template));
 716
 717 /* Generate a unique temporary file name from TEMPLATE.
 718    The last six characters of TEMPLATE must be "XXXXXX";
 719    they are replaced with a string that makes the filename unique.
 720    Returns a file descriptor open on the file for reading and writing,
 721    or -1 if it cannot create a uniquely-named file.  */
 722 extern int mkstemp __P ((char *__template));
 723
 724
 725 /* Set the end of accessible data space (aka "the break") to ADDR.
 726    Returns zero on success and -1 for errors (with errno set).  */
 727 extern int __brk __P ((__ptr_t __addr));
 728 extern int brk __P ((__ptr_t __addr));
 729
 730 #define __need_ptrdiff_t
 731 #include <stddef.h>
 732
 733 /* Increase or decrease the end of accessible data space by DELTA bytes.
 734    If successful, returns the address the previous end of data space
 735    (i.e. the beginning of the new space, if DELTA > 0);
 736    returns (void *) -1 for errors (with errno set).  */
 737 extern __ptr_t __sbrk __P ((ptrdiff_t __delta));
 738 extern __ptr_t sbrk __P ((ptrdiff_t __delta));
 739
 740
 741 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 742    This is completely system-dependent, and not often useful.
 743
 744    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 745    for errors; in many systems you cannot pass arguments or get return
 746    values for all system calls (`pipe', `fork', and `getppid' typically
 747    among them).
 748
 749    In Mach, all system calls take normal arguments and always return an
 750    error code (zero for success).  */
 751 extern long int syscall __P ((long int __sysno, ...));
 752
 753 #endif  /* Use misc.  */
 754
 755
 756 #if defined (__USE_MISC) && !defined (F_LOCK)
 757 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
 758    files consistent.  Some systems have them there and some here, and some
 759    software depends on the macros being defined without including both.  */
 760
 761 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
 762    LEN is always relative to the current file position.
 763    The CMD argument is one of the following.  */
 764
 765 #define F_ULOCK 0       /* Unlock a previously locked region.  */
 766 #define F_LOCK  1       /* Lock a region for exclusive use.  */
 767 #define F_TLOCK 2       /* Test and lock a region for exclusive use.  */
 768 #define F_TEST  3       /* Test a region for other processes locks.  */
 769
 770 extern int lockf __P ((int __fd, int __cmd, __off_t __len));
 771 #endif /* Use misc and F_LOCK not already defined.  */
 772
 773
 774 #ifdef __USE_GNU
 775
 776 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
 777    set to EINTR.  */
 778
 779 #define TEMP_FAILURE_RETRY(expression) \
 780   (__extension__                                                              \
 781     ({ long int __result;                                                     \
 782        do __result = (long int) (expression);                                 \
 783        while (__result == -1L && errno == EINTR);                             \
 784        __result; }))                                                          \
 785
 786
 787 /* This variable is set nonzero at startup if the process's effective IDs
 788    differ from its real IDs, or it is otherwise indicated that extra
 789    security should be used.  When this is set the dynamic linker ignores
 790    the various environment variables that normally affect it.  */
 791
 792 extern int __libc_enable_secure;
 793
 794 #endif
 795
 796 #ifdef __USE_POSIX
 797 /* Synchronize at least the data part of a file with the underlying
 798    media.  */
 799 extern int fdatasync __P ((int __fildes));
 800 #endif /* Use POSIX */
 801
 802 __END_DECLS
 803
 804 #endif /* unistd.h  */