posix/unistd.h

   1 /* Copyright (C) 1991-2006, 2007, 2008, 2009 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    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 #ifdef __USE_XOPEN2K8
  34 /* POSIX Standard approved as ISO/IEC 9945-1 as of September 2008.  */
  35 # define _POSIX_VERSION 200809L
  36 #elif defined __USE_XOPEN2K
  37 /* POSIX Standard approved as ISO/IEC 9945-1 as of December 2001.  */
  38 # define _POSIX_VERSION 200112L
  39 #elif defined __USE_POSIX199506
  40 /* POSIX Standard approved as ISO/IEC 9945-1 as of June 1995.  */
  41 # define _POSIX_VERSION 199506L
  42 #elif defined __USE_POSIX199309
  43 /* POSIX Standard approved as ISO/IEC 9945-1 as of September 1993.  */
  44 # define _POSIX_VERSION 199309L
  45 #else
  46 /* POSIX Standard approved as ISO/IEC 9945-1 as of September 1990.  */
  47 # define _POSIX_VERSION 199009L
  48 #endif
  49
  50 /* These are not #ifdef __USE_POSIX2 because they are
  51    in the theoretically application-owned namespace.  */
  52
  53 #ifdef __USE_XOPEN2K8
  54 # define __POSIX2_THIS_VERSION  200809L
  55 /* The utilities on GNU systems also correspond to this version.  */
  56 #elif defined __USE_XOPEN2K
  57 /* The utilities on GNU systems also correspond to this version.  */
  58 # define __POSIX2_THIS_VERSION  200112L
  59 #elif defined __USE_POSIX199506
  60 /* The utilities on GNU systems also correspond to this version.  */
  61 # define __POSIX2_THIS_VERSION  199506L
  62 #else
  63 /* The utilities on GNU systems also correspond to this version.  */
  64 # define __POSIX2_THIS_VERSION  199209L
  65 #endif
  66
  67 /* The utilities on GNU systems also correspond to this version.  */
  68 #define _POSIX2_VERSION __POSIX2_THIS_VERSION
  69
  70 /* If defined, the implementation supports the
  71    C Language Bindings Option.  */
  72 #define _POSIX2_C_BIND  __POSIX2_THIS_VERSION
  73
  74 /* If defined, the implementation supports the
  75    C Language Development Utilities Option.  */
  76 #define _POSIX2_C_DEV   __POSIX2_THIS_VERSION
  77
  78 /* If defined, the implementation supports the
  79    Software Development Utilities Option.  */
  80 #define _POSIX2_SW_DEV  __POSIX2_THIS_VERSION
  81
  82 /* If defined, the implementation supports the
  83    creation of locales with the localedef utility.  */
  84 #define _POSIX2_LOCALEDEF       __POSIX2_THIS_VERSION
  85
  86 /* X/Open version number to which the library conforms.  It is selectable.  */
  87 #ifdef __USE_XOPEN2K8
  88 # define _XOPEN_VERSION 700
  89 #elif defined __USE_XOPEN2K
  90 # define _XOPEN_VERSION 600
  91 #elif defined __USE_UNIX98
  92 # define _XOPEN_VERSION 500
  93 #else
  94 # define _XOPEN_VERSION 4
  95 #endif
  96
  97 /* Commands and utilities from XPG4 are available.  */
  98 #define _XOPEN_XCU_VERSION      4
  99
 100 /* We are compatible with the old published standards as well.  */
 101 #define _XOPEN_XPG2     1
 102 #define _XOPEN_XPG3     1
 103 #define _XOPEN_XPG4     1
 104
 105 /* The X/Open Unix extensions are available.  */
 106 #define _XOPEN_UNIX     1
 107
 108 /* Encryption is present.  */
 109 #define _XOPEN_CRYPT    1
 110
 111 /* The enhanced internationalization capabilities according to XPG4.2
 112    are present.  */
 113 #define _XOPEN_ENH_I18N 1
 114
 115 /* The legacy interfaces are also available.  */
 116 #define _XOPEN_LEGACY   1
 117
 118
 119 /* Get values of POSIX options:
 120
 121    If these symbols are defined, the corresponding features are
 122    always available.  If not, they may be available sometimes.
 123    The current values can be obtained with `sysconf'.
 124
 125    _POSIX_JOB_CONTROL           Job control is supported.
 126    _POSIX_SAVED_IDS             Processes have a saved set-user-ID
 127                                 and a saved set-group-ID.
 128    _POSIX_REALTIME_SIGNALS      Real-time, queued signals are supported.
 129    _POSIX_PRIORITY_SCHEDULING   Priority scheduling is supported.
 130    _POSIX_TIMERS                POSIX.4 clocks and timers are supported.
 131    _POSIX_ASYNCHRONOUS_IO       Asynchronous I/O is supported.
 132    _POSIX_PRIORITIZED_IO        Prioritized asynchronous I/O is supported.
 133    _POSIX_SYNCHRONIZED_IO       Synchronizing file data is supported.
 134    _POSIX_FSYNC                 The fsync function is present.
 135    _POSIX_MAPPED_FILES          Mapping of files to memory is supported.
 136    _POSIX_MEMLOCK               Locking of all memory is supported.
 137    _POSIX_MEMLOCK_RANGE         Locking of ranges of memory is supported.
 138    _POSIX_MEMORY_PROTECTION     Setting of memory protections is supported.
 139    _POSIX_MESSAGE_PASSING       POSIX.4 message queues are supported.
 140    _POSIX_SEMAPHORES            POSIX.4 counting semaphores are supported.
 141    _POSIX_SHARED_MEMORY_OBJECTS POSIX.4 shared memory objects are supported.
 142    _POSIX_THREADS               POSIX.1c pthreads are supported.
 143    _POSIX_THREAD_ATTR_STACKADDR Thread stack address attribute option supported.
 144    _POSIX_THREAD_ATTR_STACKSIZE Thread stack size attribute option supported.
 145    _POSIX_THREAD_SAFE_FUNCTIONS Thread-safe functions are supported.
 146    _POSIX_THREAD_PRIORITY_SCHEDULING
 147                                 POSIX.1c thread execution scheduling supported.
 148    _POSIX_THREAD_PRIO_INHERIT   Thread priority inheritance option supported.
 149    _POSIX_THREAD_PRIO_PROTECT   Thread priority protection option supported.
 150    _POSIX_THREAD_PROCESS_SHARED Process-shared synchronization supported.
 151    _POSIX_PII                   Protocol-independent interfaces are supported.
 152    _POSIX_PII_XTI               XTI protocol-indep. interfaces are supported.
 153    _POSIX_PII_SOCKET            Socket protocol-indep. interfaces are supported.
 154    _POSIX_PII_INTERNET          Internet family of protocols supported.
 155    _POSIX_PII_INTERNET_STREAM   Connection-mode Internet protocol supported.
 156    _POSIX_PII_INTERNET_DGRAM    Connectionless Internet protocol supported.
 157    _POSIX_PII_OSI               ISO/OSI family of protocols supported.
 158    _POSIX_PII_OSI_COTS          Connection-mode ISO/OSI service supported.
 159    _POSIX_PII_OSI_CLTS          Connectionless ISO/OSI service supported.
 160    _POSIX_POLL                  Implementation supports `poll' function.
 161    _POSIX_SELECT                Implementation supports `select' and `pselect'.
 162
 163    _XOPEN_REALTIME              X/Open realtime support is available.
 164    _XOPEN_REALTIME_THREADS      X/Open realtime thread support is available.
 165    _XOPEN_SHM                   Shared memory interface according to XPG4.2.
 166
 167    _XBS5_ILP32_OFF32            Implementation provides environment with 32-bit
 168                                 int, long, pointer, and off_t types.
 169    _XBS5_ILP32_OFFBIG           Implementation provides environment with 32-bit
 170                                 int, long, and pointer and off_t with at least
 171                                 64 bits.
 172    _XBS5_LP64_OFF64             Implementation provides environment with 32-bit
 173                                 int, and 64-bit long, pointer, and off_t types.
 174    _XBS5_LPBIG_OFFBIG           Implementation provides environment with at
 175                                 least 32 bits int and long, pointer, and off_t
 176                                 with at least 64 bits.
 177
 178    If any of these symbols is defined as -1, the corresponding option is not
 179    true for any file.  If any is defined as other than -1, the corresponding
 180    option is true for all files.  If a symbol is not defined at all, the value
 181    for a specific file can be obtained from `pathconf' and `fpathconf'.
 182
 183    _POSIX_CHOWN_RESTRICTED      Only the super user can use `chown' to change
 184                                 the owner of a file.  `chown' can only be used
 185                                 to change the group ID of a file to a group of
 186                                 which the calling process is a member.
 187    _POSIX_NO_TRUNC              Pathname components longer than
 188                                 NAME_MAX generate an error.
 189    _POSIX_VDISABLE              If defined, if the value of an element of the
 190                                 `c_cc' member of `struct termios' is
 191                                 _POSIX_VDISABLE, no character will have the
 192                                 effect associated with that element.
 193    _POSIX_SYNC_IO               Synchronous I/O may be performed.
 194    _POSIX_ASYNC_IO              Asynchronous I/O may be performed.
 195    _POSIX_PRIO_IO               Prioritized Asynchronous I/O may be performed.
 196
 197    Support for the Large File Support interface is not generally available.
 198    If it is available the following constants are defined to one.
 199    _LFS64_LARGEFILE             Low-level I/O supports large files.
 200    _LFS64_STDIO                 Standard I/O supports large files.
 201    */
 202
 203 #include <bits/posix_opt.h>
 204
 205 /* Get the environment definitions from Unix98.  */
 206 #ifdef __USE_UNIX98
 207 # include <bits/environments.h>
 208 #endif
 209
 210 /* Standard file descriptors.  */
 211 #define STDIN_FILENO    0       /* Standard input.  */
 212 #define STDOUT_FILENO   1       /* Standard output.  */
 213 #define STDERR_FILENO   2       /* Standard error output.  */
 214
 215
 216 /* All functions that are not declared anywhere else.  */
 217
 218 #include <bits/types.h>
 219
 220 #ifndef __ssize_t_defined
 221 typedef __ssize_t ssize_t;
 222 # define __ssize_t_defined
 223 #endif
 224
 225 #define __need_size_t
 226 #define __need_NULL
 227 #include <stddef.h>
 228
 229 #if defined __USE_XOPEN || defined __USE_XOPEN2K
 230 /* The Single Unix specification says that some more types are
 231    available here.  */
 232 # ifndef __gid_t_defined
 233 typedef __gid_t gid_t;
 234 #  define __gid_t_defined
 235 # endif
 236
 237 # ifndef __uid_t_defined
 238 typedef __uid_t uid_t;
 239 #  define __uid_t_defined
 240 # endif
 241
 242 # ifndef __off_t_defined
 243 #  ifndef __USE_FILE_OFFSET64
 244 typedef __off_t off_t;
 245 #  else
 246 typedef __off64_t off_t;
 247 #  endif
 248 #  define __off_t_defined
 249 # endif
 250 # if defined __USE_LARGEFILE64 && !defined __off64_t_defined
 251 typedef __off64_t off64_t;
 252 #  define __off64_t_defined
 253 # endif
 254
 255 # ifndef __useconds_t_defined
 256 typedef __useconds_t useconds_t;
 257 #  define __useconds_t_defined
 258 # endif
 259
 260 # ifndef __pid_t_defined
 261 typedef __pid_t pid_t;
 262 #  define __pid_t_defined
 263 # endif
 264 #endif  /* X/Open */
 265
 266 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 267 # ifndef __intptr_t_defined
 268 typedef __intptr_t intptr_t;
 269 #  define __intptr_t_defined
 270 # endif
 271 #endif
 272
 273 #if defined __USE_BSD || defined __USE_XOPEN
 274 # ifndef __socklen_t_defined
 275 typedef __socklen_t socklen_t;
 276 #  define __socklen_t_defined
 277 # endif
 278 #endif
 279
 280 /* Values for the second argument to access.
 281    These may be OR'd together.  */
 282 #define R_OK    4               /* Test for read permission.  */
 283 #define W_OK    2               /* Test for write permission.  */
 284 #define X_OK    1               /* Test for execute permission.  */
 285 #define F_OK    0               /* Test for existence.  */
 286
 287 /* Test for access to NAME using the real UID and real GID.  */
 288 extern int access (__const char *__name, int __type) __THROW __nonnull ((1));
 289
 290 #ifdef __USE_GNU
 291 /* Test for access to NAME using the effective UID and GID
 292    (as normal file operations use).  */
 293 extern int euidaccess (__const char *__name, int __type)
 294      __THROW __nonnull ((1));
 295
 296 /* An alias for `euidaccess', used by some other systems.  */
 297 extern int eaccess (__const char *__name, int __type)
 298      __THROW __nonnull ((1));
 299 #endif
 300
 301 #ifdef __USE_ATFILE
 302 /* Test for access to FILE relative to the directory FD is open on.
 303    If AT_EACCESS is set in FLAG, then use effective IDs like `eaccess',
 304    otherwise use real IDs like `access'.  */
 305 extern int faccessat (int __fd, __const char *__file, int __type, int __flag)
 306      __THROW __nonnull ((2)) __wur;
 307 #endif /* Use GNU.  */
 308
 309
 310 /* Values for the WHENCE argument to lseek.  */
 311 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 312 # define SEEK_SET       0       /* Seek from beginning of file.  */
 313 # define SEEK_CUR       1       /* Seek from current position.  */
 314 # define SEEK_END       2       /* Seek from end of file.  */
 315 #endif
 316
 317 #if defined __USE_BSD && !defined L_SET
 318 /* Old BSD names for the same constants; just for compatibility.  */
 319 # define L_SET          SEEK_SET
 320 # define L_INCR         SEEK_CUR
 321 # define L_XTND         SEEK_END
 322 #endif
 323
 324
 325 /* Move FD's file position to OFFSET bytes from the
 326    beginning of the file (if WHENCE is SEEK_SET),
 327    the current position (if WHENCE is SEEK_CUR),
 328    or the end of the file (if WHENCE is SEEK_END).
 329    Return the new file position.  */
 330 #ifndef __USE_FILE_OFFSET64
 331 extern __off_t lseek (int __fd, __off_t __offset, int __whence) __THROW;
 332 #else
 333 # ifdef __REDIRECT_NTH
 334 extern __off64_t __REDIRECT_NTH (lseek,
 335                                  (int __fd, __off64_t __offset, int __whence),
 336                                  lseek64);
 337 # else
 338 #  define lseek lseek64
 339 # endif
 340 #endif
 341 #ifdef __USE_LARGEFILE64
 342 extern __off64_t lseek64 (int __fd, __off64_t __offset, int __whence)
 343      __THROW;
 344 #endif
 345
 346 /* Close the file descriptor FD.
 347
 348    This function is a cancellation point and therefore not marked with
 349    __THROW.  */
 350 extern int close (int __fd);
 351
 352 /* Read NBYTES into BUF from FD.  Return the
 353    number read, -1 for errors or 0 for EOF.
 354
 355    This function is a cancellation point and therefore not marked with
 356    __THROW.  */
 357 extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur;
 358
 359 /* Write N bytes of BUF to FD.  Return the number written, or -1.
 360
 361    This function is a cancellation point and therefore not marked with
 362    __THROW.  */
 363 extern ssize_t write (int __fd, __const void *__buf, size_t __n) __wur;
 364
 365 #ifdef __USE_UNIX98
 366 # ifndef __USE_FILE_OFFSET64
 367 /* Read NBYTES into BUF from FD at the given position OFFSET without
 368    changing the file pointer.  Return the number read, -1 for errors
 369    or 0 for EOF.
 370
 371    This function is a cancellation point and therefore not marked with
 372    __THROW.  */
 373 extern ssize_t pread (int __fd, void *__buf, size_t __nbytes,
 374                       __off_t __offset) __wur;
 375
 376 /* Write N bytes of BUF to FD at the given position OFFSET without
 377    changing the file pointer.  Return the number written, or -1.
 378
 379    This function is a cancellation point and therefore not marked with
 380    __THROW.  */
 381 extern ssize_t pwrite (int __fd, __const void *__buf, size_t __n,
 382                        __off_t __offset) __wur;
 383 # else
 384 #  ifdef __REDIRECT
 385 extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes,
 386                                    __off64_t __offset),
 387                            pread64) __wur;
 388 extern ssize_t __REDIRECT (pwrite, (int __fd, __const void *__buf,
 389                                     size_t __nbytes, __off64_t __offset),
 390                            pwrite64) __wur;
 391 #  else
 392 #   define pread pread64
 393 #   define pwrite pwrite64
 394 #  endif
 395 # endif
 396
 397 # ifdef __USE_LARGEFILE64
 398 /* Read NBYTES into BUF from FD at the given position OFFSET without
 399    changing the file pointer.  Return the number read, -1 for errors
 400    or 0 for EOF.  */
 401 extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes,
 402                         __off64_t __offset) __wur;
 403 /* Write N bytes of BUF to FD at the given position OFFSET without
 404    changing the file pointer.  Return the number written, or -1.  */
 405 extern ssize_t pwrite64 (int __fd, __const void *__buf, size_t __n,
 406                          __off64_t __offset) __wur;
 407 # endif
 408 #endif
 409
 410 /* Create a one-way communication channel (pipe).
 411    If successful, two file descriptors are stored in PIPEDES;
 412    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 413    Returns 0 if successful, -1 if not.  */
 414 extern int pipe (int __pipedes[2]) __THROW __wur;
 415
 416 #ifdef __USE_GNU
 417 /* Same as pipe but apply flags passed in FLAGS to the new file
 418    descriptors.  */
 419 extern int pipe2 (int __pipedes[2], int __flags) __THROW __wur;
 420 #endif
 421
 422 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 423    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 424    The function returns the number of seconds remaining until the last
 425    alarm scheduled would have signaled, or zero if there wasn't one.
 426    There is no return value to indicate an error, but you can set `errno'
 427    to 0 and check its value after calling `alarm', and this might tell you.
 428    The signal may come late due to processor scheduling.  */
 429 extern unsigned int alarm (unsigned int __seconds) __THROW;
 430
 431 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 432    and is not ignored.  The function returns the number of seconds less
 433    than SECONDS which it actually slept (thus zero if it slept the full time).
 434    If a signal handler does a `longjmp' or modifies the handling of the
 435    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 436    signal afterwards is undefined.  There is no return value to indicate
 437    error, but if `sleep' returns SECONDS, it probably didn't work.
 438
 439    This function is a cancellation point and therefore not marked with
 440    __THROW.  */
 441 extern unsigned int sleep (unsigned int __seconds);
 442
 443 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 444 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 445    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 446    timer is reset to go off every INTERVAL microseconds thereafter.
 447    Returns the number of microseconds remaining before the alarm.  */
 448 extern __useconds_t ualarm (__useconds_t __value, __useconds_t __interval)
 449      __THROW;
 450
 451 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 452    or ignored.
 453
 454    This function is a cancellation point and therefore not marked with
 455    __THROW.  */
 456 extern int usleep (__useconds_t __useconds);
 457 #endif
 458
 459
 460 /* Suspend the process until a signal arrives.
 461    This always returns -1 and sets `errno' to EINTR.
 462
 463    This function is a cancellation point and therefore not marked with
 464    __THROW.  */
 465 extern int pause (void);
 466
 467
 468 /* Change the owner and group of FILE.  */
 469 extern int chown (__const char *__file, __uid_t __owner, __gid_t __group)
 470      __THROW __nonnull ((1)) __wur;
 471
 472 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 473 /* Change the owner and group of the file that FD is open on.  */
 474 extern int fchown (int __fd, __uid_t __owner, __gid_t __group) __THROW __wur;
 475
 476
 477 /* Change owner and group of FILE, if it is a symbolic
 478    link the ownership of the symbolic link is changed.  */
 479 extern int lchown (__const char *__file, __uid_t __owner, __gid_t __group)
 480      __THROW __nonnull ((1)) __wur;
 481
 482 #endif /* Use BSD || X/Open Unix.  */
 483
 484 #ifdef __USE_ATFILE
 485 /* Change the owner and group of FILE relative to the directory FD is open
 486    on.  */
 487 extern int fchownat (int __fd, __const char *__file, __uid_t __owner,
 488                      __gid_t __group, int __flag)
 489      __THROW __nonnull ((2)) __wur;
 490 #endif /* Use GNU.  */
 491
 492 /* Change the process's working directory to PATH.  */
 493 extern int chdir (__const char *__path) __THROW __nonnull ((1)) __wur;
 494
 495 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 496 /* Change the process's working directory to the one FD is open on.  */
 497 extern int fchdir (int __fd) __THROW __wur;
 498 #endif
 499
 500 /* Get the pathname of the current working directory,
 501    and put it in SIZE bytes of BUF.  Returns NULL if the
 502    directory couldn't be determined or SIZE was too small.
 503    If successful, returns BUF.  In GNU, if BUF is NULL,
 504    an array is allocated with `malloc'; the array is SIZE
 505    bytes long, unless SIZE == 0, in which case it is as
 506    big as necessary.  */
 507 extern char *getcwd (char *__buf, size_t __size) __THROW __wur;
 508
 509 #ifdef  __USE_GNU
 510 /* Return a malloc'd string containing the current directory name.
 511    If the environment variable `PWD' is set, and its value is correct,
 512    that value is used.  */
 513 extern char *get_current_dir_name (void) __THROW;
 514 #endif
 515
 516 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 517 /* Put the absolute pathname of the current working directory in BUF.
 518    If successful, return BUF.  If not, put an error message in
 519    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 520 extern char *getwd (char *__buf)
 521      __THROW __nonnull ((1)) __attribute_deprecated__ __wur;
 522 #endif
 523
 524
 525 /* Duplicate FD, returning a new file descriptor on the same file.  */
 526 extern int dup (int __fd) __THROW __wur;
 527
 528 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 529 extern int dup2 (int __fd, int __fd2) __THROW;
 530
 531 #ifdef __USE_GNU
 532 /* Duplicate FD to FD2, closing FD2 and making it open on the same
 533    file while setting flags according to FLAGS.  */
 534 extern int dup3 (int __fd, int __fd2, int __flags) __THROW;
 535 #endif
 536
 537 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 538 extern char **__environ;
 539 #ifdef __USE_GNU
 540 extern char **environ;
 541 #endif
 542
 543
 544 /* Replace the current process, executing PATH with arguments ARGV and
 545    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 546 extern int execve (__const char *__path, char *__const __argv[],
 547                    char *__const __envp[]) __THROW __nonnull ((1, 2));
 548
 549 #ifdef __USE_XOPEN2K8
 550 /* Execute the file FD refers to, overlaying the running program image.
 551    ARGV and ENVP are passed to the new program, as for `execve'.  */
 552 extern int fexecve (int __fd, char *__const __argv[], char *__const __envp[])
 553      __THROW __nonnull ((2));
 554 #endif
 555
 556
 557 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 558 extern int execv (__const char *__path, char *__const __argv[])
 559      __THROW __nonnull ((1, 2));
 560
 561 /* Execute PATH with all arguments after PATH until a NULL pointer,
 562    and the argument after that for environment.  */
 563 extern int execle (__const char *__path, __const char *__arg, ...)
 564      __THROW __nonnull ((1, 2));
 565
 566 /* Execute PATH with all arguments after PATH until
 567    a NULL pointer and environment from `environ'.  */
 568 extern int execl (__const char *__path, __const char *__arg, ...)
 569      __THROW __nonnull ((1, 2));
 570
 571 /* Execute FILE, searching in the `PATH' environment variable if it contains
 572    no slashes, with arguments ARGV and environment from `environ'.  */
 573 extern int execvp (__const char *__file, char *__const __argv[])
 574      __THROW __nonnull ((1, 2));
 575
 576 /* Execute FILE, searching in the `PATH' environment variable if
 577    it contains no slashes, with all arguments after FILE until a
 578    NULL pointer and environment from `environ'.  */
 579 extern int execlp (__const char *__file, __const char *__arg, ...)
 580      __THROW __nonnull ((1, 2));
 581
 582 #ifdef __USE_GNU
 583 /* Execute FILE, searching in the `PATH' environment variable if it contains
 584    no slashes, with arguments ARGV and environment from `environ'.  */
 585 extern int execvpe (__const char *__file, char *__const __argv[],
 586                     char *__const __envp[])
 587      __THROW __nonnull ((1, 2));
 588 #endif
 589
 590
 591 #if defined __USE_MISC || defined __USE_XOPEN
 592 /* Add INC to priority of the current process.  */
 593 extern int nice (int __inc) __THROW __wur;
 594 #endif
 595
 596
 597 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 598 extern void _exit (int __status) __attribute__ ((__noreturn__));
 599
 600
 601 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 602    the `_SC_*' symbols for the NAME argument to `sysconf';
 603    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 604 #include <bits/confname.h>
 605
 606 /* Get file-specific configuration information about PATH.  */
 607 extern long int pathconf (__const char *__path, int __name)
 608      __THROW __nonnull ((1));
 609
 610 /* Get file-specific configuration about descriptor FD.  */
 611 extern long int fpathconf (int __fd, int __name) __THROW;
 612
 613 /* Get the value of the system variable NAME.  */
 614 extern long int sysconf (int __name) __THROW;
 615
 616 #ifdef  __USE_POSIX2
 617 /* Get the value of the string-valued system variable NAME.  */
 618 extern size_t confstr (int __name, char *__buf, size_t __len) __THROW;
 619 #endif
 620
 621
 622 /* Get the process ID of the calling process.  */
 623 extern __pid_t getpid (void) __THROW;
 624
 625 /* Get the process ID of the calling process's parent.  */
 626 extern __pid_t getppid (void) __THROW;
 627
 628 /* Get the process group ID of the calling process.
 629    This function is different on old BSD. */
 630 #ifndef __FAVOR_BSD
 631 extern __pid_t getpgrp (void) __THROW;
 632 #else
 633 # ifdef __REDIRECT_NTH
 634 extern __pid_t __REDIRECT_NTH (getpgrp, (__pid_t __pid), __getpgid);
 635 # else
 636 #  define getpgrp __getpgid
 637 # endif
 638 #endif
 639
 640 /* Get the process group ID of process PID.  */
 641 extern __pid_t __getpgid (__pid_t __pid) __THROW;
 642 #ifdef __USE_XOPEN_EXTENDED
 643 extern __pid_t getpgid (__pid_t __pid) __THROW;
 644 #endif
 645
 646
 647 /* Set the process group ID of the process matching PID to PGID.
 648    If PID is zero, the current process's process group ID is set.
 649    If PGID is zero, the process ID of the process is used.  */
 650 extern int setpgid (__pid_t __pid, __pid_t __pgid) __THROW;
 651
 652 #if defined __USE_SVID || defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 653 /* Both System V and BSD have `setpgrp' functions, but with different
 654    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 655    (above).  The System V function takes no arguments and puts the calling
 656    process in its on group like `setpgid (0, 0)'.
 657
 658    New programs should always use `setpgid' instead.
 659
 660    The default in GNU is to provide the System V function.  The BSD
 661    function is available under -D_BSD_SOURCE.  */
 662
 663 # ifndef __FAVOR_BSD
 664
 665 /* Set the process group ID of the calling process to its own PID.
 666    This is exactly the same as `setpgid (0, 0)'.  */
 667 extern int setpgrp (void) __THROW;
 668
 669 # else
 670
 671 /* Another name for `setpgid' (above).  */
 672 #  ifdef __REDIRECT_NTH
 673 extern int __REDIRECT_NTH (setpgrp, (__pid_t __pid, __pid_t __pgrp), setpgid);
 674 #  else
 675 #   define setpgrp setpgid
 676 #  endif
 677
 678 # endif /* Favor BSD.  */
 679 #endif  /* Use SVID or BSD.  */
 680
 681 /* Create a new session with the calling process as its leader.
 682    The process group IDs of the session and the calling process
 683    are set to the process ID of the calling process, which is returned.  */
 684 extern __pid_t setsid (void) __THROW;
 685
 686 #ifdef __USE_XOPEN_EXTENDED
 687 /* Return the session ID of the given process.  */
 688 extern __pid_t getsid (__pid_t __pid) __THROW;
 689 #endif
 690
 691 /* Get the real user ID of the calling process.  */
 692 extern __uid_t getuid (void) __THROW;
 693
 694 /* Get the effective user ID of the calling process.  */
 695 extern __uid_t geteuid (void) __THROW;
 696
 697 /* Get the real group ID of the calling process.  */
 698 extern __gid_t getgid (void) __THROW;
 699
 700 /* Get the effective group ID of the calling process.  */
 701 extern __gid_t getegid (void) __THROW;
 702
 703 /* If SIZE is zero, return the number of supplementary groups
 704    the calling process is in.  Otherwise, fill in the group IDs
 705    of its supplementary groups in LIST and return the number written.  */
 706 extern int getgroups (int __size, __gid_t __list[]) __THROW __wur;
 707
 708 #ifdef  __USE_GNU
 709 /* Return nonzero iff the calling process is in group GID.  */
 710 extern int group_member (__gid_t __gid) __THROW;
 711 #endif
 712
 713 /* Set the user ID of the calling process to UID.
 714    If the calling process is the super-user, set the real
 715    and effective user IDs, and the saved set-user-ID to UID;
 716    if not, the effective user ID is set to UID.  */
 717 extern int setuid (__uid_t __uid) __THROW;
 718
 719 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 720 /* Set the real user ID of the calling process to RUID,
 721    and the effective user ID of the calling process to EUID.  */
 722 extern int setreuid (__uid_t __ruid, __uid_t __euid) __THROW;
 723 #endif
 724
 725 #if defined __USE_BSD || defined __USE_XOPEN2K
 726 /* Set the effective user ID of the calling process to UID.  */
 727 extern int seteuid (__uid_t __uid) __THROW;
 728 #endif /* Use BSD.  */
 729
 730 /* Set the group ID of the calling process to GID.
 731    If the calling process is the super-user, set the real
 732    and effective group IDs, and the saved set-group-ID to GID;
 733    if not, the effective group ID is set to GID.  */
 734 extern int setgid (__gid_t __gid) __THROW;
 735
 736 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 737 /* Set the real group ID of the calling process to RGID,
 738    and the effective group ID of the calling process to EGID.  */
 739 extern int setregid (__gid_t __rgid, __gid_t __egid) __THROW;
 740 #endif
 741
 742 #if defined __USE_BSD || defined __USE_XOPEN2K
 743 /* Set the effective group ID of the calling process to GID.  */
 744 extern int setegid (__gid_t __gid) __THROW;
 745 #endif /* Use BSD.  */
 746
 747 #ifdef __USE_GNU
 748 /* Fetch the real user ID, effective user ID, and saved-set user ID,
 749    of the calling process.  */
 750 extern int getresuid (__uid_t *__ruid, __uid_t *__euid, __uid_t *__suid)
 751      __THROW;
 752
 753 /* Fetch the real group ID, effective group ID, and saved-set group ID,
 754    of the calling process.  */
 755 extern int getresgid (__gid_t *__rgid, __gid_t *__egid, __gid_t *__sgid)
 756      __THROW;
 757
 758 /* Set the real user ID, effective user ID, and saved-set user ID,
 759    of the calling process to RUID, EUID, and SUID, respectively.  */
 760 extern int setresuid (__uid_t __ruid, __uid_t __euid, __uid_t __suid)
 761      __THROW;
 762
 763 /* Set the real group ID, effective group ID, and saved-set group ID,
 764    of the calling process to RGID, EGID, and SGID, respectively.  */
 765 extern int setresgid (__gid_t __rgid, __gid_t __egid, __gid_t __sgid)
 766      __THROW;
 767 #endif
 768
 769
 770 /* Clone the calling process, creating an exact copy.
 771    Return -1 for errors, 0 to the new process,
 772    and the process ID of the new process to the old process.  */
 773 extern __pid_t fork (void) __THROW;
 774
 775 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 776 /* Clone the calling process, but without copying the whole address space.
 777    The calling process is suspended until the new process exits or is
 778    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 779    and the process ID of the new process to the old process.  */
 780 extern __pid_t vfork (void) __THROW;
 781 #endif /* Use BSD. */
 782
 783
 784 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 785    The returned storage is good only until the next call to this function.  */
 786 extern char *ttyname (int __fd) __THROW;
 787
 788 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 789    open on in BUF.  Return 0 on success, otherwise an error number.  */
 790 extern int ttyname_r (int __fd, char *__buf, size_t __buflen)
 791      __THROW __nonnull ((2)) __wur;
 792
 793 /* Return 1 if FD is a valid descriptor associated
 794    with a terminal, zero if not.  */
 795 extern int isatty (int __fd) __THROW;
 796
 797 #if defined __USE_BSD \
 798     || (defined __USE_XOPEN_EXTENDED && !defined __USE_UNIX98)
 799 /* Return the index into the active-logins file (utmp) for
 800    the controlling terminal.  */
 801 extern int ttyslot (void) __THROW;
 802 #endif
 803
 804
 805 /* Make a link to FROM named TO.  */
 806 extern int link (__const char *__from, __const char *__to)
 807      __THROW __nonnull ((1, 2)) __wur;
 808
 809 #ifdef __USE_ATFILE
 810 /* Like link but relative paths in TO and FROM are interpreted relative
 811    to FROMFD and TOFD respectively.  */
 812 extern int linkat (int __fromfd, __const char *__from, int __tofd,
 813                    __const char *__to, int __flags)
 814      __THROW __nonnull ((2, 4)) __wur;
 815 #endif
 816
 817 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 818 /* Make a symbolic link to FROM named TO.  */
 819 extern int symlink (__const char *__from, __const char *__to)
 820      __THROW __nonnull ((1, 2)) __wur;
 821
 822 /* Read the contents of the symbolic link PATH into no more than
 823    LEN bytes of BUF.  The contents are not null-terminated.
 824    Returns the number of characters read, or -1 for errors.  */
 825 extern ssize_t readlink (__const char *__restrict __path,
 826                          char *__restrict __buf, size_t __len)
 827      __THROW __nonnull ((1, 2)) __wur;
 828 #endif /* Use BSD.  */
 829
 830 #ifdef __USE_ATFILE
 831 /* Like symlink but a relative path in TO is interpreted relative to TOFD.  */
 832 extern int symlinkat (__const char *__from, int __tofd,
 833                       __const char *__to) __THROW __nonnull ((1, 3)) __wur;
 834
 835 /* Like readlink but a relative PATH is interpreted relative to FD.  */
 836 extern ssize_t readlinkat (int __fd, __const char *__restrict __path,
 837                            char *__restrict __buf, size_t __len)
 838      __THROW __nonnull ((2, 3)) __wur;
 839 #endif
 840
 841 /* Remove the link NAME.  */
 842 extern int unlink (__const char *__name) __THROW __nonnull ((1));
 843
 844 #ifdef __USE_ATFILE
 845 /* Remove the link NAME relative to FD.  */
 846 extern int unlinkat (int __fd, __const char *__name, int __flag)
 847      __THROW __nonnull ((2));
 848 #endif
 849
 850 /* Remove the directory PATH.  */
 851 extern int rmdir (__const char *__path) __THROW __nonnull ((1));
 852
 853
 854 /* Return the foreground process group ID of FD.  */
 855 extern __pid_t tcgetpgrp (int __fd) __THROW;
 856
 857 /* Set the foreground process group ID of FD set PGRP_ID.  */
 858 extern int tcsetpgrp (int __fd, __pid_t __pgrp_id) __THROW;
 859
 860
 861 /* Return the login name of the user.
 862
 863    This function is a possible cancellation points and therefore not
 864    marked with __THROW.  */
 865 extern char *getlogin (void);
 866 #if defined __USE_REENTRANT || defined __USE_POSIX199506
 867 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 868    If it cannot be determined or some other error occurred, return the error
 869    code.  Otherwise return 0.
 870
 871    This function is a possible cancellation points and therefore not
 872    marked with __THROW.  */
 873 extern int getlogin_r (char *__name, size_t __name_len) __nonnull ((1));
 874 #endif
 875
 876 #ifdef  __USE_BSD
 877 /* Set the login name returned by `getlogin'.  */
 878 extern int setlogin (__const char *__name) __THROW __nonnull ((1));
 879 #endif
 880
 881
 882 #ifdef  __USE_POSIX2
 883 /* Get definitions and prototypes for functions to process the
 884    arguments in ARGV (ARGC of them, minus the program name) for
 885    options given in OPTS.  */
 886 # define __need_getopt
 887 # include <getopt.h>
 888 #endif
 889
 890
 891 #if defined __USE_BSD || defined __USE_UNIX98
 892 /* Put the name of the current host in no more than LEN bytes of NAME.
 893    The result is null-terminated if LEN is large enough for the full
 894    name and the terminator.  */
 895 extern int gethostname (char *__name, size_t __len) __THROW __nonnull ((1));
 896 #endif
 897
 898
 899 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_UNIX98)
 900 /* Set the name of the current host to NAME, which is LEN bytes long.
 901    This call is restricted to the super-user.  */
 902 extern int sethostname (__const char *__name, size_t __len)
 903      __THROW __nonnull ((1)) __wur;
 904
 905 /* Set the current machine's Internet number to ID.
 906    This call is restricted to the super-user.  */
 907 extern int sethostid (long int __id) __THROW __wur;
 908
 909
 910 /* Get and set the NIS (aka YP) domain name, if any.
 911    Called just like `gethostname' and `sethostname'.
 912    The NIS domain name is usually the empty string when not using NIS.  */
 913 extern int getdomainname (char *__name, size_t __len)
 914      __THROW __nonnull ((1)) __wur;
 915 extern int setdomainname (__const char *__name, size_t __len)
 916      __THROW __nonnull ((1)) __wur;
 917
 918
 919 /* Revoke access permissions to all processes currently communicating
 920    with the control terminal, and then send a SIGHUP signal to the process
 921    group of the control terminal.  */
 922 extern int vhangup (void) __THROW;
 923
 924 /* Revoke the access of all descriptors currently open on FILE.  */
 925 extern int revoke (__const char *__file) __THROW __nonnull ((1)) __wur;
 926
 927
 928 /* Enable statistical profiling, writing samples of the PC into at most
 929    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 930    is enabled, the system examines the user PC and increments
 931    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 932    disable profiling.  Returns zero on success, -1 on error.  */
 933 extern int profil (unsigned short int *__sample_buffer, size_t __size,
 934                    size_t __offset, unsigned int __scale)
 935      __THROW __nonnull ((1));
 936
 937
 938 /* Turn accounting on if NAME is an existing file.  The system will then write
 939    a record for each process as it terminates, to this file.  If NAME is NULL,
 940    turn accounting off.  This call is restricted to the super-user.  */
 941 extern int acct (__const char *__name) __THROW;
 942
 943
 944 /* Successive calls return the shells listed in `/etc/shells'.  */
 945 extern char *getusershell (void) __THROW;
 946 extern void endusershell (void) __THROW; /* Discard cached info.  */
 947 extern void setusershell (void) __THROW; /* Rewind and re-read the file.  */
 948
 949
 950 /* Put the program in the background, and dissociate from the controlling
 951    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 952    redirects stdin, stdout, and stderr to /dev/null.  */
 953 extern int daemon (int __nochdir, int __noclose) __THROW __wur;
 954 #endif /* Use BSD || X/Open.  */
 955
 956
 957 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
 958 /* Make PATH be the root directory (the starting point for absolute paths).
 959    This call is restricted to the super-user.  */
 960 extern int chroot (__const char *__path) __THROW __nonnull ((1)) __wur;
 961
 962 /* Prompt with PROMPT and read a string from the terminal without echoing.
 963    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 964 extern char *getpass (__const char *__prompt) __nonnull ((1));
 965 #endif /* Use BSD || X/Open.  */
 966
 967
 968 #if defined __USE_BSD || defined __USE_XOPEN || defined __USE_XOPEN2K
 969 /* Make all changes done to FD actually appear on disk.
 970
 971    This function is a cancellation point and therefore not marked with
 972    __THROW.  */
 973 extern int fsync (int __fd);
 974 #endif /* Use BSD || X/Open || Unix98.  */
 975
 976
 977 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 978
 979 /* Return identifier for the current host.  */
 980 extern long int gethostid (void);
 981
 982 /* Make all changes done to all files actually appear on disk.  */
 983 extern void sync (void) __THROW;
 984
 985
 986 /* Return the number of bytes in a page.  This is the system's page size,
 987    which is not necessarily the same as the hardware page size.  */
 988 extern int getpagesize (void)  __THROW __attribute__ ((__const__));
 989
 990
 991 /* Return the maximum number of file descriptors
 992    the current process could possibly have.  */
 993 extern int getdtablesize (void) __THROW;
 994
 995
 996 /* Truncate FILE to LENGTH bytes.  */
 997 # ifndef __USE_FILE_OFFSET64
 998 extern int truncate (__const char *__file, __off_t __length)
 999      __THROW __nonnull ((1)) __wur;
1000 # else
1001 #  ifdef __REDIRECT_NTH
1002 extern int __REDIRECT_NTH (truncate,
1003                            (__const char *__file, __off64_t __length),
1004                            truncate64) __nonnull ((1)) __wur;
1005 #  else
1006 #   define truncate truncate64
1007 #  endif
1008 # endif
1009 # ifdef __USE_LARGEFILE64
1010 extern int truncate64 (__const char *__file, __off64_t __length)
1011      __THROW __nonnull ((1)) __wur;
1012 # endif
1013
1014 #endif /* Use BSD || X/Open Unix.  */
1015
1016 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
1017
1018 /* Truncate the file FD is open on to LENGTH bytes.  */
1019 # ifndef __USE_FILE_OFFSET64
1020 extern int ftruncate (int __fd, __off_t __length) __THROW __wur;
1021 # else
1022 #  ifdef __REDIRECT_NTH
1023 extern int __REDIRECT_NTH (ftruncate, (int __fd, __off64_t __length),
1024                            ftruncate64) __wur;
1025 #  else
1026 #   define ftruncate ftruncate64
1027 #  endif
1028 # endif
1029 # ifdef __USE_LARGEFILE64
1030 extern int ftruncate64 (int __fd, __off64_t __length) __THROW __wur;
1031 # endif
1032
1033 #endif /* Use BSD || X/Open Unix || POSIX 2003.  */
1034
1035
1036 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
1037
1038 /* Set the end of accessible data space (aka "the break") to ADDR.
1039    Returns zero on success and -1 for errors (with errno set).  */
1040 extern int brk (void *__addr) __THROW __wur;
1041
1042 /* Increase or decrease the end of accessible data space by DELTA bytes.
1043    If successful, returns the address the previous end of data space
1044    (i.e. the beginning of the new space, if DELTA > 0);
1045    returns (void *) -1 for errors (with errno set).  */
1046 extern void *sbrk (intptr_t __delta) __THROW;
1047 #endif
1048
1049
1050 #ifdef __USE_MISC
1051 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
1052    This is completely system-dependent, and not often useful.
1053
1054    In Unix, `syscall' sets `errno' for all errors and most calls return -1
1055    for errors; in many systems you cannot pass arguments or get return
1056    values for all system calls (`pipe', `fork', and `getppid' typically
1057    among them).
1058
1059    In Mach, all system calls take normal arguments and always return an
1060    error code (zero for success).  */
1061 extern long int syscall (long int __sysno, ...) __THROW;
1062
1063 #endif  /* Use misc.  */
1064
1065
1066 #if (defined __USE_MISC || defined __USE_XOPEN_EXTENDED) && !defined F_LOCK
1067 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
1068    files consistent.  Some systems have them there and some here, and some
1069    software depends on the macros being defined without including both.  */
1070
1071 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
1072    LEN is always relative to the current file position.
1073    The CMD argument is one of the following.
1074
1075    This function is a cancellation point and therefore not marked with
1076    __THROW.  */
1077
1078 # define F_ULOCK 0      /* Unlock a previously locked region.  */
1079 # define F_LOCK  1      /* Lock a region for exclusive use.  */
1080 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
1081 # define F_TEST  3      /* Test a region for other processes locks.  */
1082
1083 # ifndef __USE_FILE_OFFSET64
1084 extern int lockf (int __fd, int __cmd, __off_t __len) __wur;
1085 # else
1086 #  ifdef __REDIRECT
1087 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len),
1088                        lockf64) __wur;
1089 #  else
1090 #   define lockf lockf64
1091 #  endif
1092 # endif
1093 # ifdef __USE_LARGEFILE64
1094 extern int lockf64 (int __fd, int __cmd, __off64_t __len) __wur;
1095 # endif
1096 #endif /* Use misc and F_LOCK not already defined.  */
1097
1098
1099 #ifdef __USE_GNU
1100
1101 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
1102    set to EINTR.  */
1103
1104 # define TEMP_FAILURE_RETRY(expression) \
1105   (__extension__                                                              \
1106     ({ long int __result;                                                     \
1107        do __result = (long int) (expression);                                 \
1108        while (__result == -1L && errno == EINTR);                             \
1109        __result; }))
1110 #endif
1111
1112 #if defined __USE_POSIX199309 || defined __USE_UNIX98
1113 /* Synchronize at least the data part of a file with the underlying
1114    media.  */
1115 extern int fdatasync (int __fildes);
1116 #endif /* Use POSIX199309 */
1117
1118
1119 /* XPG4.2 specifies that prototypes for the encryption functions must
1120    be defined here.  */
1121 #ifdef  __USE_XOPEN
1122 /* Encrypt at most 8 characters from KEY using salt to perturb DES.  */
1123 extern char *crypt (__const char *__key, __const char *__salt)
1124      __THROW __nonnull ((1, 2));
1125
1126 /* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt
1127    block in place.  */
1128 extern void encrypt (char *__block, int __edflag) __THROW __nonnull ((1));
1129
1130
1131 /* Swab pairs bytes in the first N bytes of the area pointed to by
1132    FROM and copy the result to TO.  The value of TO must not be in the
1133    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
1134    is without partner.  */
1135 extern void swab (__const void *__restrict __from, void *__restrict __to,
1136                   ssize_t __n) __THROW __nonnull ((1, 2));
1137 #endif
1138
1139
1140 /* The Single Unix specification demands this prototype to be here.
1141    It is also found in <stdio.h>.  */
1142 #ifdef __USE_XOPEN
1143 /* Return the name of the controlling terminal.  */
1144 extern char *ctermid (char *__s) __THROW;
1145 #endif
1146
1147
1148 /* Define some macros helping to catch buffer overflows.  */
1149 #if __USE_FORTIFY_LEVEL > 0 && defined __extern_always_inline
1150 # include <bits/unistd.h>
1151 #endif
1152
1153 __END_DECLS
1154
1155 #endif /* unistd.h  */