posix/unistd.h

   1 /* Copyright (C) 1991-2013 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 /*
  19  *      POSIX Standard: 2.10 Symbolic Constants         <unistd.h>
  20  */
  21
  22 #ifndef _UNISTD_H
  23 #define _UNISTD_H       1
  24
  25 #include <features.h>
  26
  27 __BEGIN_DECLS
  28
  29 /* These may be used to determine what facilities are present at compile time.
  30    Their values can be obtained at run time from `sysconf'.  */
  31
  32 #ifdef __USE_XOPEN2K8
  33 /* POSIX Standard approved as ISO/IEC 9945-1 as of September 2008.  */
  34 # define _POSIX_VERSION 200809L
  35 #elif defined __USE_XOPEN2K
  36 /* POSIX Standard approved as ISO/IEC 9945-1 as of December 2001.  */
  37 # define _POSIX_VERSION 200112L
  38 #elif defined __USE_POSIX199506
  39 /* POSIX Standard approved as ISO/IEC 9945-1 as of June 1995.  */
  40 # define _POSIX_VERSION 199506L
  41 #elif defined __USE_POSIX199309
  42 /* POSIX Standard approved as ISO/IEC 9945-1 as of September 1993.  */
  43 # define _POSIX_VERSION 199309L
  44 #else
  45 /* POSIX Standard approved as ISO/IEC 9945-1 as of September 1990.  */
  46 # define _POSIX_VERSION 199009L
  47 #endif
  48
  49 /* These are not #ifdef __USE_POSIX2 because they are
  50    in the theoretically application-owned namespace.  */
  51
  52 #ifdef __USE_XOPEN2K8
  53 # define __POSIX2_THIS_VERSION  200809L
  54 /* The utilities on GNU systems also correspond to this version.  */
  55 #elif defined __USE_XOPEN2K
  56 /* The utilities on GNU systems also correspond to this version.  */
  57 # define __POSIX2_THIS_VERSION  200112L
  58 #elif defined __USE_POSIX199506
  59 /* The utilities on GNU systems also correspond to this version.  */
  60 # define __POSIX2_THIS_VERSION  199506L
  61 #else
  62 /* The utilities on GNU systems also correspond to this version.  */
  63 # define __POSIX2_THIS_VERSION  199209L
  64 #endif
  65
  66 /* The utilities on GNU systems also correspond to this version.  */
  67 #define _POSIX2_VERSION __POSIX2_THIS_VERSION
  68
  69 /* If defined, the implementation supports the
  70    C Language Bindings Option.  */
  71 #define _POSIX2_C_BIND  __POSIX2_THIS_VERSION
  72
  73 /* If defined, the implementation supports the
  74    C Language Development Utilities Option.  */
  75 #define _POSIX2_C_DEV   __POSIX2_THIS_VERSION
  76
  77 /* If defined, the implementation supports the
  78    Software Development Utilities Option.  */
  79 #define _POSIX2_SW_DEV  __POSIX2_THIS_VERSION
  80
  81 /* If defined, the implementation supports the
  82    creation of locales with the localedef utility.  */
  83 #define _POSIX2_LOCALEDEF       __POSIX2_THIS_VERSION
  84
  85 /* X/Open version number to which the library conforms.  It is selectable.  */
  86 #ifdef __USE_XOPEN2K8
  87 # define _XOPEN_VERSION 700
  88 #elif defined __USE_XOPEN2K
  89 # define _XOPEN_VERSION 600
  90 #elif defined __USE_UNIX98
  91 # define _XOPEN_VERSION 500
  92 #else
  93 # define _XOPEN_VERSION 4
  94 #endif
  95
  96 /* Commands and utilities from XPG4 are available.  */
  97 #define _XOPEN_XCU_VERSION      4
  98
  99 /* We are compatible with the old published standards as well.  */
 100 #define _XOPEN_XPG2     1
 101 #define _XOPEN_XPG3     1
 102 #define _XOPEN_XPG4     1
 103
 104 /* The X/Open Unix extensions are available.  */
 105 #define _XOPEN_UNIX     1
 106
 107 /* Encryption is present.  */
 108 #define _XOPEN_CRYPT    1
 109
 110 /* The enhanced internationalization capabilities according to XPG4.2
 111    are present.  */
 112 #define _XOPEN_ENH_I18N 1
 113
 114 /* The legacy interfaces are also available.  */
 115 #define _XOPEN_LEGACY   1
 116
 117
 118 /* Get values of POSIX options:
 119
 120    If these symbols are defined, the corresponding features are
 121    always available.  If not, they may be available sometimes.
 122    The current values can be obtained with `sysconf'.
 123
 124    _POSIX_JOB_CONTROL           Job control is supported.
 125    _POSIX_SAVED_IDS             Processes have a saved set-user-ID
 126                                 and a saved set-group-ID.
 127    _POSIX_REALTIME_SIGNALS      Real-time, queued signals are supported.
 128    _POSIX_PRIORITY_SCHEDULING   Priority scheduling is supported.
 129    _POSIX_TIMERS                POSIX.4 clocks and timers are supported.
 130    _POSIX_ASYNCHRONOUS_IO       Asynchronous I/O is supported.
 131    _POSIX_PRIORITIZED_IO        Prioritized asynchronous I/O is supported.
 132    _POSIX_SYNCHRONIZED_IO       Synchronizing file data is supported.
 133    _POSIX_FSYNC                 The fsync function is present.
 134    _POSIX_MAPPED_FILES          Mapping of files to memory is supported.
 135    _POSIX_MEMLOCK               Locking of all memory is supported.
 136    _POSIX_MEMLOCK_RANGE         Locking of ranges of memory is supported.
 137    _POSIX_MEMORY_PROTECTION     Setting of memory protections is supported.
 138    _POSIX_MESSAGE_PASSING       POSIX.4 message queues are supported.
 139    _POSIX_SEMAPHORES            POSIX.4 counting semaphores are supported.
 140    _POSIX_SHARED_MEMORY_OBJECTS POSIX.4 shared memory objects are supported.
 141    _POSIX_THREADS               POSIX.1c pthreads are supported.
 142    _POSIX_THREAD_ATTR_STACKADDR Thread stack address attribute option supported.
 143    _POSIX_THREAD_ATTR_STACKSIZE Thread stack size attribute option supported.
 144    _POSIX_THREAD_SAFE_FUNCTIONS Thread-safe functions are supported.
 145    _POSIX_THREAD_PRIORITY_SCHEDULING
 146                                 POSIX.1c thread execution scheduling supported.
 147    _POSIX_THREAD_PRIO_INHERIT   Thread priority inheritance option supported.
 148    _POSIX_THREAD_PRIO_PROTECT   Thread priority protection option supported.
 149    _POSIX_THREAD_PROCESS_SHARED Process-shared synchronization supported.
 150    _POSIX_PII                   Protocol-independent interfaces are supported.
 151    _POSIX_PII_XTI               XTI protocol-indep. interfaces are supported.
 152    _POSIX_PII_SOCKET            Socket protocol-indep. interfaces are supported.
 153    _POSIX_PII_INTERNET          Internet family of protocols supported.
 154    _POSIX_PII_INTERNET_STREAM   Connection-mode Internet protocol supported.
 155    _POSIX_PII_INTERNET_DGRAM    Connectionless Internet protocol supported.
 156    _POSIX_PII_OSI               ISO/OSI family of protocols supported.
 157    _POSIX_PII_OSI_COTS          Connection-mode ISO/OSI service supported.
 158    _POSIX_PII_OSI_CLTS          Connectionless ISO/OSI service supported.
 159    _POSIX_POLL                  Implementation supports `poll' function.
 160    _POSIX_SELECT                Implementation supports `select' and `pselect'.
 161
 162    _XOPEN_REALTIME              X/Open realtime support is available.
 163    _XOPEN_REALTIME_THREADS      X/Open realtime thread support is available.
 164    _XOPEN_SHM                   Shared memory interface according to XPG4.2.
 165
 166    _XBS5_ILP32_OFF32            Implementation provides environment with 32-bit
 167                                 int, long, pointer, and off_t types.
 168    _XBS5_ILP32_OFFBIG           Implementation provides environment with 32-bit
 169                                 int, long, and pointer and off_t with at least
 170                                 64 bits.
 171    _XBS5_LP64_OFF64             Implementation provides environment with 32-bit
 172                                 int, and 64-bit long, pointer, and off_t types.
 173    _XBS5_LPBIG_OFFBIG           Implementation provides environment with at
 174                                 least 32 bits int and long, pointer, and off_t
 175                                 with at least 64 bits.
 176
 177    If any of these symbols is defined as -1, the corresponding option is not
 178    true for any file.  If any is defined as other than -1, the corresponding
 179    option is true for all files.  If a symbol is not defined at all, the value
 180    for a specific file can be obtained from `pathconf' and `fpathconf'.
 181
 182    _POSIX_CHOWN_RESTRICTED      Only the super user can use `chown' to change
 183                                 the owner of a file.  `chown' can only be used
 184                                 to change the group ID of a file to a group of
 185                                 which the calling process is a member.
 186    _POSIX_NO_TRUNC              Pathname components longer than
 187                                 NAME_MAX generate an error.
 188    _POSIX_VDISABLE              If defined, if the value of an element of the
 189                                 `c_cc' member of `struct termios' is
 190                                 _POSIX_VDISABLE, no character will have the
 191                                 effect associated with that element.
 192    _POSIX_SYNC_IO               Synchronous I/O may be performed.
 193    _POSIX_ASYNC_IO              Asynchronous I/O may be performed.
 194    _POSIX_PRIO_IO               Prioritized Asynchronous I/O may be performed.
 195
 196    Support for the Large File Support interface is not generally available.
 197    If it is available the following constants are defined to one.
 198    _LFS64_LARGEFILE             Low-level I/O supports large files.
 199    _LFS64_STDIO                 Standard I/O supports large files.
 200    */
 201
 202 #include <bits/posix_opt.h>
 203
 204 /* Get the environment definitions from Unix98.  */
 205 #if defined __USE_UNIX98 || defined __USE_XOPEN2K
 206 # include <bits/environments.h>
 207 #endif
 208
 209 /* Standard file descriptors.  */
 210 #define STDIN_FILENO    0       /* Standard input.  */
 211 #define STDOUT_FILENO   1       /* Standard output.  */
 212 #define STDERR_FILENO   2       /* Standard error output.  */
 213
 214
 215 /* All functions that are not declared anywhere else.  */
 216
 217 #include <bits/types.h>
 218
 219 #ifndef __ssize_t_defined
 220 typedef __ssize_t ssize_t;
 221 # define __ssize_t_defined
 222 #endif
 223
 224 #define __need_size_t
 225 #define __need_NULL
 226 #include <stddef.h>
 227
 228 #if defined __USE_XOPEN || defined __USE_XOPEN2K
 229 /* The Single Unix specification says that some more types are
 230    available here.  */
 231 # ifndef __gid_t_defined
 232 typedef __gid_t gid_t;
 233 #  define __gid_t_defined
 234 # endif
 235
 236 # ifndef __uid_t_defined
 237 typedef __uid_t uid_t;
 238 #  define __uid_t_defined
 239 # endif
 240
 241 # ifndef __off_t_defined
 242 #  ifndef __USE_FILE_OFFSET64
 243 typedef __off_t off_t;
 244 #  else
 245 typedef __off64_t off_t;
 246 #  endif
 247 #  define __off_t_defined
 248 # endif
 249 # if defined __USE_LARGEFILE64 && !defined __off64_t_defined
 250 typedef __off64_t off64_t;
 251 #  define __off64_t_defined
 252 # endif
 253
 254 # ifndef __useconds_t_defined
 255 typedef __useconds_t useconds_t;
 256 #  define __useconds_t_defined
 257 # endif
 258
 259 # ifndef __pid_t_defined
 260 typedef __pid_t pid_t;
 261 #  define __pid_t_defined
 262 # endif
 263 #endif  /* X/Open */
 264
 265 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 266 # ifndef __intptr_t_defined
 267 typedef __intptr_t intptr_t;
 268 #  define __intptr_t_defined
 269 # endif
 270 #endif
 271
 272 #if defined __USE_BSD || defined __USE_XOPEN
 273 # ifndef __socklen_t_defined
 274 typedef __socklen_t socklen_t;
 275 #  define __socklen_t_defined
 276 # endif
 277 #endif
 278
 279 /* Values for the second argument to access.
 280    These may be OR'd together.  */
 281 #define R_OK    4               /* Test for read permission.  */
 282 #define W_OK    2               /* Test for write permission.  */
 283 #define X_OK    1               /* Test for execute permission.  */
 284 #define F_OK    0               /* Test for existence.  */
 285
 286 /* Test for access to NAME using the real UID and real GID.  */
 287 extern int access (const char *__name, int __type) __THROW __nonnull ((1));
 288
 289 #ifdef __USE_GNU
 290 /* Test for access to NAME using the effective UID and GID
 291    (as normal file operations use).  */
 292 extern int euidaccess (const char *__name, int __type)
 293      __THROW __nonnull ((1));
 294
 295 /* An alias for `euidaccess', used by some other systems.  */
 296 extern int eaccess (const char *__name, int __type)
 297      __THROW __nonnull ((1));
 298 #endif
 299
 300 #ifdef __USE_ATFILE
 301 /* Test for access to FILE relative to the directory FD is open on.
 302    If AT_EACCESS is set in FLAG, then use effective IDs like `eaccess',
 303    otherwise use real IDs like `access'.  */
 304 extern int faccessat (int __fd, const char *__file, int __type, int __flag)
 305      __THROW __nonnull ((2)) __wur;
 306 #endif /* Use GNU.  */
 307
 308
 309 /* Values for the WHENCE argument to lseek.  */
 310 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 311 # define SEEK_SET       0       /* Seek from beginning of file.  */
 312 # define SEEK_CUR       1       /* Seek from current position.  */
 313 # define SEEK_END       2       /* Seek from end of file.  */
 314 # ifdef __USE_GNU
 315 #  define SEEK_DATA     3       /* Seek to next data.  */
 316 #  define SEEK_HOLE     4       /* Seek to next hole.  */
 317 # endif
 318 #endif
 319
 320 #if defined __USE_BSD && !defined L_SET
 321 /* Old BSD names for the same constants; just for compatibility.  */
 322 # define L_SET          SEEK_SET
 323 # define L_INCR         SEEK_CUR
 324 # define L_XTND         SEEK_END
 325 #endif
 326
 327
 328 /* Move FD's file position to OFFSET bytes from the
 329    beginning of the file (if WHENCE is SEEK_SET),
 330    the current position (if WHENCE is SEEK_CUR),
 331    or the end of the file (if WHENCE is SEEK_END).
 332    Return the new file position.  */
 333 #ifndef __USE_FILE_OFFSET64
 334 extern __off_t lseek (int __fd, __off_t __offset, int __whence) __THROW;
 335 #else
 336 # ifdef __REDIRECT_NTH
 337 extern __off64_t __REDIRECT_NTH (lseek,
 338                                  (int __fd, __off64_t __offset, int __whence),
 339                                  lseek64);
 340 # else
 341 #  define lseek lseek64
 342 # endif
 343 #endif
 344 #ifdef __USE_LARGEFILE64
 345 extern __off64_t lseek64 (int __fd, __off64_t __offset, int __whence)
 346      __THROW;
 347 #endif
 348
 349 /* Close the file descriptor FD.
 350
 351    This function is a cancellation point and therefore not marked with
 352    __THROW.  */
 353 extern int close (int __fd);
 354
 355 /* Read NBYTES into BUF from FD.  Return the
 356    number read, -1 for errors or 0 for EOF.
 357
 358    This function is a cancellation point and therefore not marked with
 359    __THROW.  */
 360 extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur;
 361
 362 /* Write N bytes of BUF to FD.  Return the number written, or -1.
 363
 364    This function is a cancellation point and therefore not marked with
 365    __THROW.  */
 366 extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur;
 367
 368 #if defined __USE_UNIX98 || defined __USE_XOPEN2K8
 369 # ifndef __USE_FILE_OFFSET64
 370 /* Read NBYTES into BUF from FD at the given position OFFSET without
 371    changing the file pointer.  Return the number read, -1 for errors
 372    or 0 for EOF.
 373
 374    This function is a cancellation point and therefore not marked with
 375    __THROW.  */
 376 extern ssize_t pread (int __fd, void *__buf, size_t __nbytes,
 377                       __off_t __offset) __wur;
 378
 379 /* Write N bytes of BUF to FD at the given position OFFSET without
 380    changing the file pointer.  Return the number written, or -1.
 381
 382    This function is a cancellation point and therefore not marked with
 383    __THROW.  */
 384 extern ssize_t pwrite (int __fd, const void *__buf, size_t __n,
 385                        __off_t __offset) __wur;
 386 # else
 387 #  ifdef __REDIRECT
 388 extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes,
 389                                    __off64_t __offset),
 390                            pread64) __wur;
 391 extern ssize_t __REDIRECT (pwrite, (int __fd, const void *__buf,
 392                                     size_t __nbytes, __off64_t __offset),
 393                            pwrite64) __wur;
 394 #  else
 395 #   define pread pread64
 396 #   define pwrite pwrite64
 397 #  endif
 398 # endif
 399
 400 # ifdef __USE_LARGEFILE64
 401 /* Read NBYTES into BUF from FD at the given position OFFSET without
 402    changing the file pointer.  Return the number read, -1 for errors
 403    or 0 for EOF.  */
 404 extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes,
 405                         __off64_t __offset) __wur;
 406 /* Write N bytes of BUF to FD at the given position OFFSET without
 407    changing the file pointer.  Return the number written, or -1.  */
 408 extern ssize_t pwrite64 (int __fd, const void *__buf, size_t __n,
 409                          __off64_t __offset) __wur;
 410 # endif
 411 #endif
 412
 413 /* Create a one-way communication channel (pipe).
 414    If successful, two file descriptors are stored in PIPEDES;
 415    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 416    Returns 0 if successful, -1 if not.  */
 417 extern int pipe (int __pipedes[2]) __THROW __wur;
 418
 419 #ifdef __USE_GNU
 420 /* Same as pipe but apply flags passed in FLAGS to the new file
 421    descriptors.  */
 422 extern int pipe2 (int __pipedes[2], int __flags) __THROW __wur;
 423 #endif
 424
 425 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 426    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 427    The function returns the number of seconds remaining until the last
 428    alarm scheduled would have signaled, or zero if there wasn't one.
 429    There is no return value to indicate an error, but you can set `errno'
 430    to 0 and check its value after calling `alarm', and this might tell you.
 431    The signal may come late due to processor scheduling.  */
 432 extern unsigned int alarm (unsigned int __seconds) __THROW;
 433
 434 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 435    and is not ignored.  The function returns the number of seconds less
 436    than SECONDS which it actually slept (thus zero if it slept the full time).
 437    If a signal handler does a `longjmp' or modifies the handling of the
 438    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 439    signal afterwards is undefined.  There is no return value to indicate
 440    error, but if `sleep' returns SECONDS, it probably didn't work.
 441
 442    This function is a cancellation point and therefore not marked with
 443    __THROW.  */
 444 extern unsigned int sleep (unsigned int __seconds);
 445
 446 #if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
 447     || defined __USE_BSD
 448 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 449    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 450    timer is reset to go off every INTERVAL microseconds thereafter.
 451    Returns the number of microseconds remaining before the alarm.  */
 452 extern __useconds_t ualarm (__useconds_t __value, __useconds_t __interval)
 453      __THROW;
 454
 455 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 456    or ignored.
 457
 458    This function is a cancellation point and therefore not marked with
 459    __THROW.  */
 460 extern int usleep (__useconds_t __useconds);
 461 #endif
 462
 463
 464 /* Suspend the process until a signal arrives.
 465    This always returns -1 and sets `errno' to EINTR.
 466
 467    This function is a cancellation point and therefore not marked with
 468    __THROW.  */
 469 extern int pause (void);
 470
 471
 472 /* Change the owner and group of FILE.  */
 473 extern int chown (const char *__file, __uid_t __owner, __gid_t __group)
 474      __THROW __nonnull ((1)) __wur;
 475
 476 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 477 /* Change the owner and group of the file that FD is open on.  */
 478 extern int fchown (int __fd, __uid_t __owner, __gid_t __group) __THROW __wur;
 479
 480
 481 /* Change owner and group of FILE, if it is a symbolic
 482    link the ownership of the symbolic link is changed.  */
 483 extern int lchown (const char *__file, __uid_t __owner, __gid_t __group)
 484      __THROW __nonnull ((1)) __wur;
 485
 486 #endif /* Use BSD || X/Open Unix.  */
 487
 488 #ifdef __USE_ATFILE
 489 /* Change the owner and group of FILE relative to the directory FD is open
 490    on.  */
 491 extern int fchownat (int __fd, const char *__file, __uid_t __owner,
 492                      __gid_t __group, int __flag)
 493      __THROW __nonnull ((2)) __wur;
 494 #endif /* Use GNU.  */
 495
 496 /* Change the process's working directory to PATH.  */
 497 extern int chdir (const char *__path) __THROW __nonnull ((1)) __wur;
 498
 499 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 500 /* Change the process's working directory to the one FD is open on.  */
 501 extern int fchdir (int __fd) __THROW __wur;
 502 #endif
 503
 504 /* Get the pathname of the current working directory,
 505    and put it in SIZE bytes of BUF.  Returns NULL if the
 506    directory couldn't be determined or SIZE was too small.
 507    If successful, returns BUF.  In GNU, if BUF is NULL,
 508    an array is allocated with `malloc'; the array is SIZE
 509    bytes long, unless SIZE == 0, in which case it is as
 510    big as necessary.  */
 511 extern char *getcwd (char *__buf, size_t __size) __THROW __wur;
 512
 513 #ifdef  __USE_GNU
 514 /* Return a malloc'd string containing the current directory name.
 515    If the environment variable `PWD' is set, and its value is correct,
 516    that value is used.  */
 517 extern char *get_current_dir_name (void) __THROW;
 518 #endif
 519
 520 #if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
 521     || defined __USE_BSD
 522 /* Put the absolute pathname of the current working directory in BUF.
 523    If successful, return BUF.  If not, put an error message in
 524    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 525 extern char *getwd (char *__buf)
 526      __THROW __nonnull ((1)) __attribute_deprecated__ __wur;
 527 #endif
 528
 529
 530 /* Duplicate FD, returning a new file descriptor on the same file.  */
 531 extern int dup (int __fd) __THROW __wur;
 532
 533 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 534 extern int dup2 (int __fd, int __fd2) __THROW;
 535
 536 #ifdef __USE_GNU
 537 /* Duplicate FD to FD2, closing FD2 and making it open on the same
 538    file while setting flags according to FLAGS.  */
 539 extern int dup3 (int __fd, int __fd2, int __flags) __THROW;
 540 #endif
 541
 542 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 543 extern char **__environ;
 544 #ifdef __USE_GNU
 545 extern char **environ;
 546 #endif
 547
 548
 549 /* Replace the current process, executing PATH with arguments ARGV and
 550    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 551 extern int execve (const char *__path, char *const __argv[],
 552                    char *const __envp[]) __THROW __nonnull ((1, 2));
 553
 554 #ifdef __USE_XOPEN2K8
 555 /* Execute the file FD refers to, overlaying the running program image.
 556    ARGV and ENVP are passed to the new program, as for `execve'.  */
 557 extern int fexecve (int __fd, char *const __argv[], char *const __envp[])
 558      __THROW __nonnull ((2));
 559 #endif
 560
 561
 562 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 563 extern int execv (const char *__path, char *const __argv[])
 564      __THROW __nonnull ((1, 2));
 565
 566 /* Execute PATH with all arguments after PATH until a NULL pointer,
 567    and the argument after that for environment.  */
 568 extern int execle (const char *__path, const char *__arg, ...)
 569      __THROW __nonnull ((1, 2));
 570
 571 /* Execute PATH with all arguments after PATH until
 572    a NULL pointer and environment from `environ'.  */
 573 extern int execl (const char *__path, const char *__arg, ...)
 574      __THROW __nonnull ((1, 2));
 575
 576 /* Execute FILE, searching in the `PATH' environment variable if it contains
 577    no slashes, with arguments ARGV and environment from `environ'.  */
 578 extern int execvp (const char *__file, char *const __argv[])
 579      __THROW __nonnull ((1, 2));
 580
 581 /* Execute FILE, searching in the `PATH' environment variable if
 582    it contains no slashes, with all arguments after FILE until a
 583    NULL pointer and environment from `environ'.  */
 584 extern int execlp (const char *__file, const char *__arg, ...)
 585      __THROW __nonnull ((1, 2));
 586
 587 #ifdef __USE_GNU
 588 /* Execute FILE, searching in the `PATH' environment variable if it contains
 589    no slashes, with arguments ARGV and environment from `environ'.  */
 590 extern int execvpe (const char *__file, char *const __argv[],
 591                     char *const __envp[])
 592      __THROW __nonnull ((1, 2));
 593 #endif
 594
 595
 596 #if defined __USE_MISC || defined __USE_XOPEN
 597 /* Add INC to priority of the current process.  */
 598 extern int nice (int __inc) __THROW __wur;
 599 #endif
 600
 601
 602 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 603 extern void _exit (int __status) __attribute__ ((__noreturn__));
 604
 605
 606 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 607    the `_SC_*' symbols for the NAME argument to `sysconf';
 608    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 609 #include <bits/confname.h>
 610
 611 /* Get file-specific configuration information about PATH.  */
 612 extern long int pathconf (const char *__path, int __name)
 613      __THROW __nonnull ((1));
 614
 615 /* Get file-specific configuration about descriptor FD.  */
 616 extern long int fpathconf (int __fd, int __name) __THROW;
 617
 618 /* Get the value of the system variable NAME.  */
 619 extern long int sysconf (int __name) __THROW;
 620
 621 #ifdef  __USE_POSIX2
 622 /* Get the value of the string-valued system variable NAME.  */
 623 extern size_t confstr (int __name, char *__buf, size_t __len) __THROW;
 624 #endif
 625
 626
 627 /* Get the process ID of the calling process.  */
 628 extern __pid_t getpid (void) __THROW;
 629
 630 /* Get the process ID of the calling process's parent.  */
 631 extern __pid_t getppid (void) __THROW;
 632
 633 /* Get the process group ID of the calling process.
 634    This function is different on old BSD. */
 635 #ifndef __FAVOR_BSD
 636 extern __pid_t getpgrp (void) __THROW;
 637 #else
 638 # ifdef __REDIRECT_NTH
 639 extern __pid_t __REDIRECT_NTH (getpgrp, (__pid_t __pid), __getpgid);
 640 # else
 641 #  define getpgrp __getpgid
 642 # endif
 643 #endif
 644
 645 /* Get the process group ID of process PID.  */
 646 extern __pid_t __getpgid (__pid_t __pid) __THROW;
 647 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 648 extern __pid_t getpgid (__pid_t __pid) __THROW;
 649 #endif
 650
 651
 652 /* Set the process group ID of the process matching PID to PGID.
 653    If PID is zero, the current process's process group ID is set.
 654    If PGID is zero, the process ID of the process is used.  */
 655 extern int setpgid (__pid_t __pid, __pid_t __pgid) __THROW;
 656
 657 #if defined __USE_SVID || defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 658 /* Both System V and BSD have `setpgrp' functions, but with different
 659    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 660    (above).  The System V function takes no arguments and puts the calling
 661    process in its on group like `setpgid (0, 0)'.
 662
 663    New programs should always use `setpgid' instead.
 664
 665    The default in GNU is to provide the System V function.  The BSD
 666    function is available under -D_BSD_SOURCE.  */
 667
 668 # ifndef __FAVOR_BSD
 669
 670 /* Set the process group ID of the calling process to its own PID.
 671    This is exactly the same as `setpgid (0, 0)'.  */
 672 extern int setpgrp (void) __THROW;
 673
 674 # else
 675
 676 /* Another name for `setpgid' (above).  */
 677 #  ifdef __REDIRECT_NTH
 678 extern int __REDIRECT_NTH (setpgrp, (__pid_t __pid, __pid_t __pgrp), setpgid);
 679 #  else
 680 #   define setpgrp setpgid
 681 #  endif
 682
 683 # endif /* Favor BSD.  */
 684 #endif  /* Use SVID or BSD.  */
 685
 686 /* Create a new session with the calling process as its leader.
 687    The process group IDs of the session and the calling process
 688    are set to the process ID of the calling process, which is returned.  */
 689 extern __pid_t setsid (void) __THROW;
 690
 691 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 692 /* Return the session ID of the given process.  */
 693 extern __pid_t getsid (__pid_t __pid) __THROW;
 694 #endif
 695
 696 /* Get the real user ID of the calling process.  */
 697 extern __uid_t getuid (void) __THROW;
 698
 699 /* Get the effective user ID of the calling process.  */
 700 extern __uid_t geteuid (void) __THROW;
 701
 702 /* Get the real group ID of the calling process.  */
 703 extern __gid_t getgid (void) __THROW;
 704
 705 /* Get the effective group ID of the calling process.  */
 706 extern __gid_t getegid (void) __THROW;
 707
 708 /* If SIZE is zero, return the number of supplementary groups
 709    the calling process is in.  Otherwise, fill in the group IDs
 710    of its supplementary groups in LIST and return the number written.  */
 711 extern int getgroups (int __size, __gid_t __list[]) __THROW __wur;
 712
 713 #ifdef  __USE_GNU
 714 /* Return nonzero iff the calling process is in group GID.  */
 715 extern int group_member (__gid_t __gid) __THROW;
 716 #endif
 717
 718 /* Set the user ID of the calling process to UID.
 719    If the calling process is the super-user, set the real
 720    and effective user IDs, and the saved set-user-ID to UID;
 721    if not, the effective user ID is set to UID.  */
 722 extern int setuid (__uid_t __uid) __THROW __wur;
 723
 724 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 725 /* Set the real user ID of the calling process to RUID,
 726    and the effective user ID of the calling process to EUID.  */
 727 extern int setreuid (__uid_t __ruid, __uid_t __euid) __THROW __wur;
 728 #endif
 729
 730 #if defined __USE_BSD || defined __USE_XOPEN2K
 731 /* Set the effective user ID of the calling process to UID.  */
 732 extern int seteuid (__uid_t __uid) __THROW __wur;
 733 #endif /* Use BSD.  */
 734
 735 /* Set the group ID of the calling process to GID.
 736    If the calling process is the super-user, set the real
 737    and effective group IDs, and the saved set-group-ID to GID;
 738    if not, the effective group ID is set to GID.  */
 739 extern int setgid (__gid_t __gid) __THROW __wur;
 740
 741 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 742 /* Set the real group ID of the calling process to RGID,
 743    and the effective group ID of the calling process to EGID.  */
 744 extern int setregid (__gid_t __rgid, __gid_t __egid) __THROW __wur;
 745 #endif
 746
 747 #if defined __USE_BSD || defined __USE_XOPEN2K
 748 /* Set the effective group ID of the calling process to GID.  */
 749 extern int setegid (__gid_t __gid) __THROW __wur;
 750 #endif /* Use BSD.  */
 751
 752 #ifdef __USE_GNU
 753 /* Fetch the real user ID, effective user ID, and saved-set user ID,
 754    of the calling process.  */
 755 extern int getresuid (__uid_t *__ruid, __uid_t *__euid, __uid_t *__suid)
 756      __THROW;
 757
 758 /* Fetch the real group ID, effective group ID, and saved-set group ID,
 759    of the calling process.  */
 760 extern int getresgid (__gid_t *__rgid, __gid_t *__egid, __gid_t *__sgid)
 761      __THROW;
 762
 763 /* Set the real user ID, effective user ID, and saved-set user ID,
 764    of the calling process to RUID, EUID, and SUID, respectively.  */
 765 extern int setresuid (__uid_t __ruid, __uid_t __euid, __uid_t __suid)
 766      __THROW __wur;
 767
 768 /* Set the real group ID, effective group ID, and saved-set group ID,
 769    of the calling process to RGID, EGID, and SGID, respectively.  */
 770 extern int setresgid (__gid_t __rgid, __gid_t __egid, __gid_t __sgid)
 771      __THROW __wur;
 772 #endif
 773
 774
 775 /* Clone the calling process, creating an exact copy.
 776    Return -1 for errors, 0 to the new process,
 777    and the process ID of the new process to the old process.  */
 778 extern __pid_t fork (void) __THROWNL;
 779
 780 #if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
 781     || defined __USE_BSD
 782 /* Clone the calling process, but without copying the whole address space.
 783    The calling process is suspended until the new process exits or is
 784    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 785    and the process ID of the new process to the old process.  */
 786 extern __pid_t vfork (void) __THROW;
 787 #endif /* Use BSD or XPG < 7. */
 788
 789
 790 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 791    The returned storage is good only until the next call to this function.  */
 792 extern char *ttyname (int __fd) __THROW;
 793
 794 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 795    open on in BUF.  Return 0 on success, otherwise an error number.  */
 796 extern int ttyname_r (int __fd, char *__buf, size_t __buflen)
 797      __THROW __nonnull ((2)) __wur;
 798
 799 /* Return 1 if FD is a valid descriptor associated
 800    with a terminal, zero if not.  */
 801 extern int isatty (int __fd) __THROW;
 802
 803 #if defined __USE_BSD \
 804     || (defined __USE_XOPEN_EXTENDED && !defined __USE_UNIX98)
 805 /* Return the index into the active-logins file (utmp) for
 806    the controlling terminal.  */
 807 extern int ttyslot (void) __THROW;
 808 #endif
 809
 810
 811 /* Make a link to FROM named TO.  */
 812 extern int link (const char *__from, const char *__to)
 813      __THROW __nonnull ((1, 2)) __wur;
 814
 815 #ifdef __USE_ATFILE
 816 /* Like link but relative paths in TO and FROM are interpreted relative
 817    to FROMFD and TOFD respectively.  */
 818 extern int linkat (int __fromfd, const char *__from, int __tofd,
 819                    const char *__to, int __flags)
 820      __THROW __nonnull ((2, 4)) __wur;
 821 #endif
 822
 823 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 824 /* Make a symbolic link to FROM named TO.  */
 825 extern int symlink (const char *__from, const char *__to)
 826      __THROW __nonnull ((1, 2)) __wur;
 827
 828 /* Read the contents of the symbolic link PATH into no more than
 829    LEN bytes of BUF.  The contents are not null-terminated.
 830    Returns the number of characters read, or -1 for errors.  */
 831 extern ssize_t readlink (const char *__restrict __path,
 832                          char *__restrict __buf, size_t __len)
 833      __THROW __nonnull ((1, 2)) __wur;
 834 #endif /* Use BSD.  */
 835
 836 #ifdef __USE_ATFILE
 837 /* Like symlink but a relative path in TO is interpreted relative to TOFD.  */
 838 extern int symlinkat (const char *__from, int __tofd,
 839                       const char *__to) __THROW __nonnull ((1, 3)) __wur;
 840
 841 /* Like readlink but a relative PATH is interpreted relative to FD.  */
 842 extern ssize_t readlinkat (int __fd, const char *__restrict __path,
 843                            char *__restrict __buf, size_t __len)
 844      __THROW __nonnull ((2, 3)) __wur;
 845 #endif
 846
 847 /* Remove the link NAME.  */
 848 extern int unlink (const char *__name) __THROW __nonnull ((1));
 849
 850 #ifdef __USE_ATFILE
 851 /* Remove the link NAME relative to FD.  */
 852 extern int unlinkat (int __fd, const char *__name, int __flag)
 853      __THROW __nonnull ((2));
 854 #endif
 855
 856 /* Remove the directory PATH.  */
 857 extern int rmdir (const char *__path) __THROW __nonnull ((1));
 858
 859
 860 /* Return the foreground process group ID of FD.  */
 861 extern __pid_t tcgetpgrp (int __fd) __THROW;
 862
 863 /* Set the foreground process group ID of FD set PGRP_ID.  */
 864 extern int tcsetpgrp (int __fd, __pid_t __pgrp_id) __THROW;
 865
 866
 867 /* Return the login name of the user.
 868
 869    This function is a possible cancellation point and therefore not
 870    marked with __THROW.  */
 871 extern char *getlogin (void);
 872 #if defined __USE_REENTRANT || defined __USE_POSIX199506
 873 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 874    If it cannot be determined or some other error occurred, return the error
 875    code.  Otherwise return 0.
 876
 877    This function is a possible cancellation point and therefore not
 878    marked with __THROW.  */
 879 extern int getlogin_r (char *__name, size_t __name_len) __nonnull ((1));
 880 #endif
 881
 882 #ifdef  __USE_BSD
 883 /* Set the login name returned by `getlogin'.  */
 884 extern int setlogin (const char *__name) __THROW __nonnull ((1));
 885 #endif
 886
 887
 888 #ifdef  __USE_POSIX2
 889 /* Get definitions and prototypes for functions to process the
 890    arguments in ARGV (ARGC of them, minus the program name) for
 891    options given in OPTS.  */
 892 # define __need_getopt
 893 # include <getopt.h>
 894 #endif
 895
 896
 897 #if defined __USE_BSD || defined __USE_UNIX98 || defined __USE_XOPEN2K
 898 /* Put the name of the current host in no more than LEN bytes of NAME.
 899    The result is null-terminated if LEN is large enough for the full
 900    name and the terminator.  */
 901 extern int gethostname (char *__name, size_t __len) __THROW __nonnull ((1));
 902 #endif
 903
 904
 905 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_UNIX98)
 906 /* Set the name of the current host to NAME, which is LEN bytes long.
 907    This call is restricted to the super-user.  */
 908 extern int sethostname (const char *__name, size_t __len)
 909      __THROW __nonnull ((1)) __wur;
 910
 911 /* Set the current machine's Internet number to ID.
 912    This call is restricted to the super-user.  */
 913 extern int sethostid (long int __id) __THROW __wur;
 914
 915
 916 /* Get and set the NIS (aka YP) domain name, if any.
 917    Called just like `gethostname' and `sethostname'.
 918    The NIS domain name is usually the empty string when not using NIS.  */
 919 extern int getdomainname (char *__name, size_t __len)
 920      __THROW __nonnull ((1)) __wur;
 921 extern int setdomainname (const char *__name, size_t __len)
 922      __THROW __nonnull ((1)) __wur;
 923
 924
 925 /* Revoke access permissions to all processes currently communicating
 926    with the control terminal, and then send a SIGHUP signal to the process
 927    group of the control terminal.  */
 928 extern int vhangup (void) __THROW;
 929
 930 /* Revoke the access of all descriptors currently open on FILE.  */
 931 extern int revoke (const char *__file) __THROW __nonnull ((1)) __wur;
 932
 933
 934 /* Enable statistical profiling, writing samples of the PC into at most
 935    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 936    is enabled, the system examines the user PC and increments
 937    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 938    disable profiling.  Returns zero on success, -1 on error.  */
 939 extern int profil (unsigned short int *__sample_buffer, size_t __size,
 940                    size_t __offset, unsigned int __scale)
 941      __THROW __nonnull ((1));
 942
 943
 944 /* Turn accounting on if NAME is an existing file.  The system will then write
 945    a record for each process as it terminates, to this file.  If NAME is NULL,
 946    turn accounting off.  This call is restricted to the super-user.  */
 947 extern int acct (const char *__name) __THROW;
 948
 949
 950 /* Successive calls return the shells listed in `/etc/shells'.  */
 951 extern char *getusershell (void) __THROW;
 952 extern void endusershell (void) __THROW; /* Discard cached info.  */
 953 extern void setusershell (void) __THROW; /* Rewind and re-read the file.  */
 954
 955
 956 /* Put the program in the background, and dissociate from the controlling
 957    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 958    redirects stdin, stdout, and stderr to /dev/null.  */
 959 extern int daemon (int __nochdir, int __noclose) __THROW __wur;
 960 #endif /* Use BSD || X/Open.  */
 961
 962
 963 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
 964 /* Make PATH be the root directory (the starting point for absolute paths).
 965    This call is restricted to the super-user.  */
 966 extern int chroot (const char *__path) __THROW __nonnull ((1)) __wur;
 967
 968 /* Prompt with PROMPT and read a string from the terminal without echoing.
 969    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 970 extern char *getpass (const char *__prompt) __nonnull ((1));
 971 #endif /* Use BSD || X/Open.  */
 972
 973
 974 /* Make all changes done to FD actually appear on disk.
 975
 976    This function is a cancellation point and therefore not marked with
 977    __THROW.  */
 978 extern int fsync (int __fd);
 979
 980
 981 #ifdef __USE_GNU
 982 /* Make all changes done to all files on the file system associated
 983    with FD actually appear on disk.  */
 984 extern int syncfs (int __fd) __THROW;
 985 #endif
 986
 987
 988 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 989
 990 /* Return identifier for the current host.  */
 991 extern long int gethostid (void);
 992
 993 /* Make all changes done to all files actually appear on disk.  */
 994 extern void sync (void) __THROW;
 995
 996
 997 # if defined __USE_BSD || !defined __USE_XOPEN2K
 998 /* Return the number of bytes in a page.  This is the system's page size,
 999    which is not necessarily the same as the hardware page size.  */
1000 extern int getpagesize (void)  __THROW __attribute__ ((__const__));
1001
1002
1003 /* Return the maximum number of file descriptors
1004    the current process could possibly have.  */
1005 extern int getdtablesize (void) __THROW;
1006 # endif
1007
1008 #endif /* Use BSD || X/Open Unix.  */
1009
1010
1011 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
1012
1013 /* Truncate FILE to LENGTH bytes.  */
1014 # ifndef __USE_FILE_OFFSET64
1015 extern int truncate (const char *__file, __off_t __length)
1016      __THROW __nonnull ((1)) __wur;
1017 # else
1018 #  ifdef __REDIRECT_NTH
1019 extern int __REDIRECT_NTH (truncate,
1020                            (const char *__file, __off64_t __length),
1021                            truncate64) __nonnull ((1)) __wur;
1022 #  else
1023 #   define truncate truncate64
1024 #  endif
1025 # endif
1026 # ifdef __USE_LARGEFILE64
1027 extern int truncate64 (const char *__file, __off64_t __length)
1028      __THROW __nonnull ((1)) __wur;
1029 # endif
1030
1031 #endif /* Use BSD || X/Open Unix || POSIX 2008.  */
1032
1033 #if defined __USE_BSD || defined __USE_POSIX199309 \
1034     || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
1035
1036 /* Truncate the file FD is open on to LENGTH bytes.  */
1037 # ifndef __USE_FILE_OFFSET64
1038 extern int ftruncate (int __fd, __off_t __length) __THROW __wur;
1039 # else
1040 #  ifdef __REDIRECT_NTH
1041 extern int __REDIRECT_NTH (ftruncate, (int __fd, __off64_t __length),
1042                            ftruncate64) __wur;
1043 #  else
1044 #   define ftruncate ftruncate64
1045 #  endif
1046 # endif
1047 # ifdef __USE_LARGEFILE64
1048 extern int ftruncate64 (int __fd, __off64_t __length) __THROW __wur;
1049 # endif
1050
1051 #endif /* Use BSD || POSIX.1b || X/Open Unix || XPG6.  */
1052
1053
1054 #if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K) \
1055     || defined __USE_MISC
1056
1057 /* Set the end of accessible data space (aka "the break") to ADDR.
1058    Returns zero on success and -1 for errors (with errno set).  */
1059 extern int brk (void *__addr) __THROW __wur;
1060
1061 /* Increase or decrease the end of accessible data space by DELTA bytes.
1062    If successful, returns the address the previous end of data space
1063    (i.e. the beginning of the new space, if DELTA > 0);
1064    returns (void *) -1 for errors (with errno set).  */
1065 extern void *sbrk (intptr_t __delta) __THROW;
1066 #endif
1067
1068
1069 #ifdef __USE_MISC
1070 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
1071    This is completely system-dependent, and not often useful.
1072
1073    In Unix, `syscall' sets `errno' for all errors and most calls return -1
1074    for errors; in many systems you cannot pass arguments or get return
1075    values for all system calls (`pipe', `fork', and `getppid' typically
1076    among them).
1077
1078    In Mach, all system calls take normal arguments and always return an
1079    error code (zero for success).  */
1080 extern long int syscall (long int __sysno, ...) __THROW;
1081
1082 #endif  /* Use misc.  */
1083
1084
1085 #if (defined __USE_MISC || defined __USE_XOPEN_EXTENDED) && !defined F_LOCK
1086 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
1087    files consistent.  Some systems have them there and some here, and some
1088    software depends on the macros being defined without including both.  */
1089
1090 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
1091    LEN is always relative to the current file position.
1092    The CMD argument is one of the following.
1093
1094    This function is a cancellation point and therefore not marked with
1095    __THROW.  */
1096
1097 # define F_ULOCK 0      /* Unlock a previously locked region.  */
1098 # define F_LOCK  1      /* Lock a region for exclusive use.  */
1099 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
1100 # define F_TEST  3      /* Test a region for other processes locks.  */
1101
1102 # ifndef __USE_FILE_OFFSET64
1103 extern int lockf (int __fd, int __cmd, __off_t __len) __wur;
1104 # else
1105 #  ifdef __REDIRECT
1106 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len),
1107                        lockf64) __wur;
1108 #  else
1109 #   define lockf lockf64
1110 #  endif
1111 # endif
1112 # ifdef __USE_LARGEFILE64
1113 extern int lockf64 (int __fd, int __cmd, __off64_t __len) __wur;
1114 # endif
1115 #endif /* Use misc and F_LOCK not already defined.  */
1116
1117
1118 #ifdef __USE_GNU
1119
1120 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
1121    set to EINTR.  */
1122
1123 # define TEMP_FAILURE_RETRY(expression) \
1124   (__extension__                                                              \
1125     ({ long int __result;                                                     \
1126        do __result = (long int) (expression);                                 \
1127        while (__result == -1L && errno == EINTR);                             \
1128        __result; }))
1129 #endif
1130
1131 #if defined __USE_POSIX199309 || defined __USE_UNIX98
1132 /* Synchronize at least the data part of a file with the underlying
1133    media.  */
1134 extern int fdatasync (int __fildes);
1135 #endif /* Use POSIX199309 */
1136
1137
1138 /* XPG4.2 specifies that prototypes for the encryption functions must
1139    be defined here.  */
1140 #ifdef  __USE_XOPEN
1141 /* Encrypt at most 8 characters from KEY using salt to perturb DES.  */
1142 extern char *crypt (const char *__key, const char *__salt)
1143      __THROW __nonnull ((1, 2));
1144
1145 /* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt
1146    block in place.  */
1147 extern void encrypt (char *__block, int __edflag) __THROW __nonnull ((1));
1148
1149
1150 /* Swab pairs bytes in the first N bytes of the area pointed to by
1151    FROM and copy the result to TO.  The value of TO must not be in the
1152    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
1153    is without partner.  */
1154 extern void swab (const void *__restrict __from, void *__restrict __to,
1155                   ssize_t __n) __THROW __nonnull ((1, 2));
1156 #endif
1157
1158
1159 /* The Single Unix specification demands this prototype to be here.
1160    It is also found in <stdio.h>.  */
1161 #if defined __USE_XOPEN && !defined __USE_XOPEN2K
1162 /* Return the name of the controlling terminal.  */
1163 extern char *ctermid (char *__s) __THROW;
1164 #endif
1165
1166
1167 /* Define some macros helping to catch buffer overflows.  */
1168 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
1169 # include <bits/unistd.h>
1170 #endif
1171
1172 __END_DECLS
1173
1174 #endif /* unistd.h  */