posix/unistd.h

   1 /* Copyright (C) 1991-2023 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    <https://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 /* This symbol was required until the 2001 edition of POSIX.  */
  70 #define _POSIX2_C_VERSION       __POSIX2_THIS_VERSION
  71
  72 /* If defined, the implementation supports the
  73    C Language Bindings Option.  */
  74 #define _POSIX2_C_BIND  __POSIX2_THIS_VERSION
  75
  76 /* If defined, the implementation supports the
  77    C Language Development Utilities Option.  */
  78 #define _POSIX2_C_DEV   __POSIX2_THIS_VERSION
  79
  80 /* If defined, the implementation supports the
  81    Software Development Utilities Option.  */
  82 #define _POSIX2_SW_DEV  __POSIX2_THIS_VERSION
  83
  84 /* If defined, the implementation supports the
  85    creation of locales with the localedef utility.  */
  86 #define _POSIX2_LOCALEDEF       __POSIX2_THIS_VERSION
  87
  88 /* X/Open version number to which the library conforms.  It is selectable.  */
  89 #ifdef __USE_XOPEN2K8
  90 # define _XOPEN_VERSION 700
  91 #elif defined __USE_XOPEN2K
  92 # define _XOPEN_VERSION 600
  93 #elif defined __USE_UNIX98
  94 # define _XOPEN_VERSION 500
  95 #else
  96 # define _XOPEN_VERSION 4
  97 #endif
  98
  99 /* Commands and utilities from XPG4 are available.  */
 100 #define _XOPEN_XCU_VERSION      4
 101
 102 /* We are compatible with the old published standards as well.  */
 103 #define _XOPEN_XPG2     1
 104 #define _XOPEN_XPG3     1
 105 #define _XOPEN_XPG4     1
 106
 107 /* The X/Open Unix extensions are available.  */
 108 #define _XOPEN_UNIX     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_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_MISC || 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
 299 /* Execute program relative to a directory file descriptor.  */
 300 extern int execveat (int __fd, const char *__path, char *const __argv[],
 301                      char *const __envp[], int __flags)
 302     __THROW __nonnull ((2, 3));
 303 #endif
 304
 305 #ifdef __USE_ATFILE
 306 /* Test for access to FILE relative to the directory FD is open on.
 307    If AT_EACCESS is set in FLAG, then use effective IDs like `eaccess',
 308    otherwise use real IDs like `access'.  */
 309 extern int faccessat (int __fd, const char *__file, int __type, int __flag)
 310      __THROW __nonnull ((2)) __wur;
 311 #endif /* Use GNU.  */
 312
 313
 314 /* Values for the WHENCE argument to lseek.  */
 315 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 316 # define SEEK_SET       0       /* Seek from beginning of file.  */
 317 # define SEEK_CUR       1       /* Seek from current position.  */
 318 # define SEEK_END       2       /* Seek from end of file.  */
 319 # ifdef __USE_GNU
 320 #  define SEEK_DATA     3       /* Seek to next data.  */
 321 #  define SEEK_HOLE     4       /* Seek to next hole.  */
 322 # endif
 323 #endif
 324
 325 #if defined __USE_MISC && !defined L_SET
 326 /* Old BSD names for the same constants; just for compatibility.  */
 327 # define L_SET          SEEK_SET
 328 # define L_INCR         SEEK_CUR
 329 # define L_XTND         SEEK_END
 330 #endif
 331
 332
 333 /* Move FD's file position to OFFSET bytes from the
 334    beginning of the file (if WHENCE is SEEK_SET),
 335    the current position (if WHENCE is SEEK_CUR),
 336    or the end of the file (if WHENCE is SEEK_END).
 337    Return the new file position.  */
 338 #ifndef __USE_FILE_OFFSET64
 339 extern __off_t lseek (int __fd, __off_t __offset, int __whence) __THROW;
 340 #else
 341 # ifdef __REDIRECT_NTH
 342 extern __off64_t __REDIRECT_NTH (lseek,
 343                                  (int __fd, __off64_t __offset, int __whence),
 344                                  lseek64);
 345 # else
 346 #  define lseek lseek64
 347 # endif
 348 #endif
 349 #ifdef __USE_LARGEFILE64
 350 extern __off64_t lseek64 (int __fd, __off64_t __offset, int __whence)
 351      __THROW;
 352 #endif
 353
 354 /* Close the file descriptor FD.
 355
 356    This function is a cancellation point and therefore not marked with
 357    __THROW.  */
 358 extern int close (int __fd);
 359
 360 #ifdef __USE_MISC
 361 /* Close all open file descriptors greater than or equal to LOWFD.
 362    Negative LOWFD is clamped to 0.  */
 363 extern void closefrom (int __lowfd) __THROW;
 364 #endif
 365
 366 /* Read NBYTES into BUF from FD.  Return the
 367    number read, -1 for errors or 0 for EOF.
 368
 369    This function is a cancellation point and therefore not marked with
 370    __THROW.  */
 371 extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur
 372     __fortified_attr_access (__write_only__, 2, 3);
 373
 374 /* Write N bytes of BUF to FD.  Return the number written, or -1.
 375
 376    This function is a cancellation point and therefore not marked with
 377    __THROW.  */
 378 extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur
 379     __attr_access ((__read_only__, 2, 3));
 380
 381 #if defined __USE_UNIX98 || defined __USE_XOPEN2K8
 382 # ifndef __USE_FILE_OFFSET64
 383 /* Read NBYTES into BUF from FD at the given position OFFSET without
 384    changing the file pointer.  Return the number read, -1 for errors
 385    or 0 for EOF.
 386
 387    This function is a cancellation point and therefore not marked with
 388    __THROW.  */
 389 extern ssize_t pread (int __fd, void *__buf, size_t __nbytes,
 390                       __off_t __offset) __wur
 391     __fortified_attr_access (__write_only__, 2, 3);
 392
 393 /* Write N bytes of BUF to FD at the given position OFFSET without
 394    changing the file pointer.  Return the number written, or -1.
 395
 396    This function is a cancellation point and therefore not marked with
 397    __THROW.  */
 398 extern ssize_t pwrite (int __fd, const void *__buf, size_t __n,
 399                        __off_t __offset) __wur
 400     __attr_access ((__read_only__, 2, 3));
 401
 402 # else
 403 #  ifdef __REDIRECT
 404 extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes,
 405                                    __off64_t __offset),
 406                            pread64) __wur
 407     __fortified_attr_access (__write_only__, 2, 3);
 408 extern ssize_t __REDIRECT (pwrite, (int __fd, const void *__buf,
 409                                     size_t __nbytes, __off64_t __offset),
 410                            pwrite64) __wur
 411     __attr_access ((__read_only__, 2, 3));
 412 #  else
 413 #   define pread pread64
 414 #   define pwrite pwrite64
 415 #  endif
 416 # endif
 417
 418 # ifdef __USE_LARGEFILE64
 419 /* Read NBYTES into BUF from FD at the given position OFFSET without
 420    changing the file pointer.  Return the number read, -1 for errors
 421    or 0 for EOF.  */
 422 extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes,
 423                         __off64_t __offset) __wur
 424     __fortified_attr_access (__write_only__, 2, 3);
 425 /* Write N bytes of BUF to FD at the given position OFFSET without
 426    changing the file pointer.  Return the number written, or -1.  */
 427 extern ssize_t pwrite64 (int __fd, const void *__buf, size_t __n,
 428                          __off64_t __offset) __wur
 429     __attr_access ((__read_only__, 2, 3));
 430 # endif
 431 #endif
 432
 433 /* Create a one-way communication channel (pipe).
 434    If successful, two file descriptors are stored in PIPEDES;
 435    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 436    Returns 0 if successful, -1 if not.  */
 437 extern int pipe (int __pipedes[2]) __THROW __wur;
 438
 439 #ifdef __USE_GNU
 440 /* Same as pipe but apply flags passed in FLAGS to the new file
 441    descriptors.  */
 442 extern int pipe2 (int __pipedes[2], int __flags) __THROW __wur;
 443 #endif
 444
 445 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 446    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 447    The function returns the number of seconds remaining until the last
 448    alarm scheduled would have signaled, or zero if there wasn't one.
 449    There is no return value to indicate an error, but you can set `errno'
 450    to 0 and check its value after calling `alarm', and this might tell you.
 451    The signal may come late due to processor scheduling.  */
 452 extern unsigned int alarm (unsigned int __seconds) __THROW;
 453
 454 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 455    and is not ignored.  The function returns the number of seconds less
 456    than SECONDS which it actually slept (thus zero if it slept the full time).
 457    If a signal handler does a `longjmp' or modifies the handling of the
 458    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 459    signal afterwards is undefined.  There is no return value to indicate
 460    error, but if `sleep' returns SECONDS, it probably didn't work.
 461
 462    This function is a cancellation point and therefore not marked with
 463    __THROW.  */
 464 extern unsigned int sleep (unsigned int __seconds);
 465
 466 #if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
 467     || defined __USE_MISC
 468 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 469    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 470    timer is reset to go off every INTERVAL microseconds thereafter.
 471    Returns the number of microseconds remaining before the alarm.  */
 472 extern __useconds_t ualarm (__useconds_t __value, __useconds_t __interval)
 473      __THROW;
 474
 475 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 476    or ignored.
 477
 478    This function is a cancellation point and therefore not marked with
 479    __THROW.  */
 480 extern int usleep (__useconds_t __useconds);
 481 #endif
 482
 483
 484 /* Suspend the process until a signal arrives.
 485    This always returns -1 and sets `errno' to EINTR.
 486
 487    This function is a cancellation point and therefore not marked with
 488    __THROW.  */
 489 extern int pause (void);
 490
 491
 492 /* Change the owner and group of FILE.  */
 493 extern int chown (const char *__file, __uid_t __owner, __gid_t __group)
 494      __THROW __nonnull ((1)) __wur;
 495
 496 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 497 /* Change the owner and group of the file that FD is open on.  */
 498 extern int fchown (int __fd, __uid_t __owner, __gid_t __group) __THROW __wur;
 499
 500
 501 /* Change owner and group of FILE, if it is a symbolic
 502    link the ownership of the symbolic link is changed.  */
 503 extern int lchown (const char *__file, __uid_t __owner, __gid_t __group)
 504      __THROW __nonnull ((1)) __wur;
 505
 506 #endif /* Use X/Open Unix.  */
 507
 508 #ifdef __USE_ATFILE
 509 /* Change the owner and group of FILE relative to the directory FD is open
 510    on.  */
 511 extern int fchownat (int __fd, const char *__file, __uid_t __owner,
 512                      __gid_t __group, int __flag)
 513      __THROW __nonnull ((2)) __wur;
 514 #endif /* Use GNU.  */
 515
 516 /* Change the process's working directory to PATH.  */
 517 extern int chdir (const char *__path) __THROW __nonnull ((1)) __wur;
 518
 519 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 520 /* Change the process's working directory to the one FD is open on.  */
 521 extern int fchdir (int __fd) __THROW __wur;
 522 #endif
 523
 524 /* Get the pathname of the current working directory,
 525    and put it in SIZE bytes of BUF.  Returns NULL if the
 526    directory couldn't be determined or SIZE was too small.
 527    If successful, returns BUF.  In GNU, if BUF is NULL,
 528    an array is allocated with `malloc'; the array is SIZE
 529    bytes long, unless SIZE == 0, in which case it is as
 530    big as necessary.  */
 531 extern char *getcwd (char *__buf, size_t __size) __THROW __wur;
 532
 533 #ifdef  __USE_GNU
 534 /* Return a malloc'd string containing the current directory name.
 535    If the environment variable `PWD' is set, and its value is correct,
 536    that value is used.  */
 537 extern char *get_current_dir_name (void) __THROW;
 538 #endif
 539
 540 #if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K8) \
 541     || defined __USE_MISC
 542 /* Put the absolute pathname of the current working directory in BUF.
 543    If successful, return BUF.  If not, put an error message in
 544    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 545 extern char *getwd (char *__buf)
 546      __THROW __nonnull ((1)) __attribute_deprecated__ __wur
 547     __attr_access ((__write_only__, 1));
 548 #endif
 549
 550
 551 /* Duplicate FD, returning a new file descriptor on the same file.  */
 552 extern int dup (int __fd) __THROW __wur;
 553
 554 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 555 extern int dup2 (int __fd, int __fd2) __THROW;
 556
 557 #ifdef __USE_GNU
 558 /* Duplicate FD to FD2, closing FD2 and making it open on the same
 559    file while setting flags according to FLAGS.  */
 560 extern int dup3 (int __fd, int __fd2, int __flags) __THROW;
 561 #endif
 562
 563 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 564 extern char **__environ;
 565 #ifdef __USE_GNU
 566 extern char **environ;
 567 #endif
 568
 569
 570 /* Replace the current process, executing PATH with arguments ARGV and
 571    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 572 extern int execve (const char *__path, char *const __argv[],
 573                    char *const __envp[]) __THROW __nonnull ((1, 2));
 574
 575 #ifdef __USE_XOPEN2K8
 576 /* Execute the file FD refers to, overlaying the running program image.
 577    ARGV and ENVP are passed to the new program, as for `execve'.  */
 578 extern int fexecve (int __fd, char *const __argv[], char *const __envp[])
 579      __THROW __nonnull ((2));
 580 #endif
 581
 582
 583 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 584 extern int execv (const char *__path, char *const __argv[])
 585      __THROW __nonnull ((1, 2));
 586
 587 /* Execute PATH with all arguments after PATH until a NULL pointer,
 588    and the argument after that for environment.  */
 589 extern int execle (const char *__path, const char *__arg, ...)
 590      __THROW __nonnull ((1, 2));
 591
 592 /* Execute PATH with all arguments after PATH until
 593    a NULL pointer and environment from `environ'.  */
 594 extern int execl (const char *__path, const char *__arg, ...)
 595      __THROW __nonnull ((1, 2));
 596
 597 /* Execute FILE, searching in the `PATH' environment variable if it contains
 598    no slashes, with arguments ARGV and environment from `environ'.  */
 599 extern int execvp (const char *__file, char *const __argv[])
 600      __THROW __nonnull ((1, 2));
 601
 602 /* Execute FILE, searching in the `PATH' environment variable if
 603    it contains no slashes, with all arguments after FILE until a
 604    NULL pointer and environment from `environ'.  */
 605 extern int execlp (const char *__file, const char *__arg, ...)
 606      __THROW __nonnull ((1, 2));
 607
 608 #ifdef __USE_GNU
 609 /* Execute FILE, searching in the `PATH' environment variable if it contains
 610    no slashes, with arguments ARGV and environment from `environ'.  */
 611 extern int execvpe (const char *__file, char *const __argv[],
 612                     char *const __envp[])
 613      __THROW __nonnull ((1, 2));
 614 #endif
 615
 616
 617 #if defined __USE_MISC || defined __USE_XOPEN
 618 /* Add INC to priority of the current process.  */
 619 extern int nice (int __inc) __THROW __wur;
 620 #endif
 621
 622
 623 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 624 extern void _exit (int __status) __attribute__ ((__noreturn__));
 625
 626
 627 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 628    the `_SC_*' symbols for the NAME argument to `sysconf';
 629    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 630 #include <bits/confname.h>
 631
 632 /* Get file-specific configuration information about PATH.  */
 633 extern long int pathconf (const char *__path, int __name)
 634      __THROW __nonnull ((1));
 635
 636 /* Get file-specific configuration about descriptor FD.  */
 637 extern long int fpathconf (int __fd, int __name) __THROW;
 638
 639 /* Get the value of the system variable NAME.  */
 640 extern long int sysconf (int __name) __THROW;
 641
 642 #ifdef  __USE_POSIX2
 643 /* Get the value of the string-valued system variable NAME.  */
 644 extern size_t confstr (int __name, char *__buf, size_t __len) __THROW
 645     __fortified_attr_access (__write_only__, 2, 3);
 646 #endif
 647
 648
 649 /* Get the process ID of the calling process.  */
 650 extern __pid_t getpid (void) __THROW;
 651
 652 /* Get the process ID of the calling process's parent.  */
 653 extern __pid_t getppid (void) __THROW;
 654
 655 /* Get the process group ID of the calling process.  */
 656 extern __pid_t getpgrp (void) __THROW;
 657
 658 /* Get the process group ID of process PID.  */
 659 extern __pid_t __getpgid (__pid_t __pid) __THROW;
 660 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
 661 extern __pid_t getpgid (__pid_t __pid) __THROW;
 662 #endif
 663
 664
 665 /* Set the process group ID of the process matching PID to PGID.
 666    If PID is zero, the current process's process group ID is set.
 667    If PGID is zero, the process ID of the process is used.  */
 668 extern int setpgid (__pid_t __pid, __pid_t __pgid) __THROW;
 669
 670 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 671 /* Both System V and BSD have `setpgrp' functions, but with different
 672    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 673    (above).  The System V function takes no arguments and puts the calling
 674    process in its on group like `setpgid (0, 0)'.
 675
 676    New programs should always use `setpgid' instead.
 677
 678    GNU provides the POSIX.1 function.  */
 679
 680 /* Set the process group ID of the calling process to its own PID.
 681    This is exactly the same as `setpgid (0, 0)'.  */
 682 extern int setpgrp (void) __THROW;
 683
 684 #endif  /* Use misc or X/Open.  */
 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     __fortified_attr_access (__write_only__, 2, 1);
 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_MISC || 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 #ifdef __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 POSIX.1-2001.  */
 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_MISC || 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 #ifdef __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 POSIX.1-2001.  */
 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_MISC
 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 misc or XPG < 7. */
 788
 789 #ifdef __USE_GNU
 790 /* This is similar to fork, however it does not run the atfork handlers
 791    neither reinitialize any internal locks in multithread case.
 792    Different than fork, _Fork is async-signal-safe.  */
 793 extern __pid_t _Fork (void) __THROW;
 794 #endif
 795
 796
 797 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 798    The returned storage is good only until the next call to this function.  */
 799 extern char *ttyname (int __fd) __THROW;
 800
 801 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 802    open on in BUF.  Return 0 on success, otherwise an error number.  */
 803 extern int ttyname_r (int __fd, char *__buf, size_t __buflen)
 804      __THROW __nonnull ((2)) __wur
 805      __fortified_attr_access (__write_only__, 2, 3);
 806
 807 /* Return 1 if FD is a valid descriptor associated
 808    with a terminal, zero if not.  */
 809 extern int isatty (int __fd) __THROW;
 810
 811 #ifdef __USE_MISC
 812 /* Return the index into the active-logins file (utmp) for
 813    the controlling terminal.  */
 814 extern int ttyslot (void) __THROW;
 815 #endif
 816
 817
 818 /* Make a link to FROM named TO.  */
 819 extern int link (const char *__from, const char *__to)
 820      __THROW __nonnull ((1, 2)) __wur;
 821
 822 #ifdef __USE_ATFILE
 823 /* Like link but relative paths in TO and FROM are interpreted relative
 824    to FROMFD and TOFD respectively.  */
 825 extern int linkat (int __fromfd, const char *__from, int __tofd,
 826                    const char *__to, int __flags)
 827      __THROW __nonnull ((2, 4)) __wur;
 828 #endif
 829
 830 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 831 /* Make a symbolic link to FROM named TO.  */
 832 extern int symlink (const char *__from, const char *__to)
 833      __THROW __nonnull ((1, 2)) __wur;
 834
 835 /* Read the contents of the symbolic link PATH into no more than
 836    LEN bytes of BUF.  The contents are not null-terminated.
 837    Returns the number of characters read, or -1 for errors.  */
 838 extern ssize_t readlink (const char *__restrict __path,
 839                          char *__restrict __buf, size_t __len)
 840      __THROW __nonnull ((1, 2)) __wur
 841      __fortified_attr_access (__write_only__, 2, 3);
 842
 843 #endif /* Use POSIX.1-2001.  */
 844
 845 #ifdef __USE_ATFILE
 846 /* Like symlink but a relative path in TO is interpreted relative to TOFD.  */
 847 extern int symlinkat (const char *__from, int __tofd,
 848                       const char *__to) __THROW __nonnull ((1, 3)) __wur;
 849
 850 /* Like readlink but a relative PATH is interpreted relative to FD.  */
 851 extern ssize_t readlinkat (int __fd, const char *__restrict __path,
 852                            char *__restrict __buf, size_t __len)
 853      __THROW __nonnull ((2, 3)) __wur
 854      __fortified_attr_access (__write_only__, 3, 4);
 855 #endif
 856
 857 /* Remove the link NAME.  */
 858 extern int unlink (const char *__name) __THROW __nonnull ((1));
 859
 860 #ifdef __USE_ATFILE
 861 /* Remove the link NAME relative to FD.  */
 862 extern int unlinkat (int __fd, const char *__name, int __flag)
 863      __THROW __nonnull ((2));
 864 #endif
 865
 866 /* Remove the directory PATH.  */
 867 extern int rmdir (const char *__path) __THROW __nonnull ((1));
 868
 869
 870 /* Return the foreground process group ID of FD.  */
 871 extern __pid_t tcgetpgrp (int __fd) __THROW;
 872
 873 /* Set the foreground process group ID of FD set PGRP_ID.  */
 874 extern int tcsetpgrp (int __fd, __pid_t __pgrp_id) __THROW;
 875
 876
 877 /* Return the login name of the user.
 878
 879    This function is a possible cancellation point and therefore not
 880    marked with __THROW.  */
 881 extern char *getlogin (void);
 882 #ifdef __USE_POSIX199506
 883 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 884    If it cannot be determined or some other error occurred, return the error
 885    code.  Otherwise return 0.
 886
 887    This function is a possible cancellation point and therefore not
 888    marked with __THROW.  */
 889 extern int getlogin_r (char *__name, size_t __name_len) __nonnull ((1))
 890     __fortified_attr_access (__write_only__, 1, 2);
 891 #endif
 892
 893 #ifdef  __USE_MISC
 894 /* Set the login name returned by `getlogin'.  */
 895 extern int setlogin (const char *__name) __THROW __nonnull ((1));
 896 #endif
 897
 898
 899 #ifdef  __USE_POSIX2
 900 /* Get definitions and prototypes for functions to process the
 901    arguments in ARGV (ARGC of them, minus the program name) for
 902    options given in OPTS.  */
 903 # include <bits/getopt_posix.h>
 904 #endif
 905
 906
 907 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 908 /* Put the name of the current host in no more than LEN bytes of NAME.
 909    The result is null-terminated if LEN is large enough for the full
 910    name and the terminator.  */
 911 extern int gethostname (char *__name, size_t __len) __THROW __nonnull ((1))
 912     __fortified_attr_access (__write_only__, 1, 2);
 913 #endif
 914
 915
 916 #if defined __USE_MISC
 917 /* Set the name of the current host to NAME, which is LEN bytes long.
 918    This call is restricted to the super-user.  */
 919 extern int sethostname (const char *__name, size_t __len)
 920      __THROW __nonnull ((1)) __wur __attr_access ((__read_only__, 1, 2));
 921
 922 /* Set the current machine's Internet number to ID.
 923    This call is restricted to the super-user.  */
 924 extern int sethostid (long int __id) __THROW __wur;
 925
 926
 927 /* Get and set the NIS (aka YP) domain name, if any.
 928    Called just like `gethostname' and `sethostname'.
 929    The NIS domain name is usually the empty string when not using NIS.  */
 930 extern int getdomainname (char *__name, size_t __len)
 931      __THROW __nonnull ((1)) __wur
 932      __fortified_attr_access (__write_only__, 1, 2);
 933 extern int setdomainname (const char *__name, size_t __len)
 934      __THROW __nonnull ((1)) __wur __attr_access ((__read_only__, 1, 2));
 935
 936 /* Revoke access permissions to all processes currently communicating
 937    with the control terminal, and then send a SIGHUP signal to the process
 938    group of the control terminal.  */
 939 extern int vhangup (void) __THROW;
 940
 941 /* Revoke the access of all descriptors currently open on FILE.  */
 942 extern int revoke (const char *__file) __THROW __nonnull ((1)) __wur;
 943
 944
 945 /* Enable statistical profiling, writing samples of the PC into at most
 946    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 947    is enabled, the system examines the user PC and increments
 948    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 949    disable profiling.  Returns zero on success, -1 on error.  */
 950 extern int profil (unsigned short int *__sample_buffer, size_t __size,
 951                    size_t __offset, unsigned int __scale)
 952      __THROW __nonnull ((1));
 953
 954
 955 /* Turn accounting on if NAME is an existing file.  The system will then write
 956    a record for each process as it terminates, to this file.  If NAME is NULL,
 957    turn accounting off.  This call is restricted to the super-user.  */
 958 extern int acct (const char *__name) __THROW;
 959
 960
 961 /* Successive calls return the shells listed in `/etc/shells'.  */
 962 extern char *getusershell (void) __THROW;
 963 extern void endusershell (void) __THROW; /* Discard cached info.  */
 964 extern void setusershell (void) __THROW; /* Rewind and re-read the file.  */
 965
 966
 967 /* Put the program in the background, and dissociate from the controlling
 968    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 969    redirects stdin, stdout, and stderr to /dev/null.  */
 970 extern int daemon (int __nochdir, int __noclose) __THROW __wur;
 971 #endif /* Use misc.  */
 972
 973
 974 #if defined __USE_MISC || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
 975 /* Make PATH be the root directory (the starting point for absolute paths).
 976    This call is restricted to the super-user.  */
 977 extern int chroot (const char *__path) __THROW __nonnull ((1)) __wur;
 978
 979 /* Prompt with PROMPT and read a string from the terminal without echoing.
 980    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 981 extern char *getpass (const char *__prompt) __nonnull ((1));
 982 #endif /* Use misc || X/Open.  */
 983
 984
 985 /* Make all changes done to FD actually appear on disk.
 986
 987    This function is a cancellation point and therefore not marked with
 988    __THROW.  */
 989 extern int fsync (int __fd);
 990
 991
 992 #ifdef __USE_GNU
 993 /* Make all changes done to all files on the file system associated
 994    with FD actually appear on disk.  */
 995 extern int syncfs (int __fd) __THROW;
 996 #endif
 997
 998
 999 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
1000
1001 /* Return identifier for the current host.  */
1002 extern long int gethostid (void);
1003
1004 /* Make all changes done to all files actually appear on disk.  */
1005 extern void sync (void) __THROW;
1006
1007
1008 # if defined __USE_MISC || !defined __USE_XOPEN2K
1009 /* Return the number of bytes in a page.  This is the system's page size,
1010    which is not necessarily the same as the hardware page size.  */
1011 extern int getpagesize (void)  __THROW __attribute__ ((__const__));
1012
1013
1014 /* Return the maximum number of file descriptors
1015    the current process could possibly have.  */
1016 extern int getdtablesize (void) __THROW;
1017 # endif
1018
1019 #endif /* Use misc || X/Open Unix.  */
1020
1021
1022 #if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
1023
1024 /* Truncate FILE to LENGTH bytes.  */
1025 # ifndef __USE_FILE_OFFSET64
1026 extern int truncate (const char *__file, __off_t __length)
1027      __THROW __nonnull ((1)) __wur;
1028 # else
1029 #  ifdef __REDIRECT_NTH
1030 extern int __REDIRECT_NTH (truncate,
1031                            (const char *__file, __off64_t __length),
1032                            truncate64) __nonnull ((1)) __wur;
1033 #  else
1034 #   define truncate truncate64
1035 #  endif
1036 # endif
1037 # ifdef __USE_LARGEFILE64
1038 extern int truncate64 (const char *__file, __off64_t __length)
1039      __THROW __nonnull ((1)) __wur;
1040 # endif
1041
1042 #endif /* Use X/Open Unix || POSIX 2008.  */
1043
1044 #if defined __USE_POSIX199309 \
1045     || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
1046
1047 /* Truncate the file FD is open on to LENGTH bytes.  */
1048 # ifndef __USE_FILE_OFFSET64
1049 extern int ftruncate (int __fd, __off_t __length) __THROW __wur;
1050 # else
1051 #  ifdef __REDIRECT_NTH
1052 extern int __REDIRECT_NTH (ftruncate, (int __fd, __off64_t __length),
1053                            ftruncate64) __wur;
1054 #  else
1055 #   define ftruncate ftruncate64
1056 #  endif
1057 # endif
1058 # ifdef __USE_LARGEFILE64
1059 extern int ftruncate64 (int __fd, __off64_t __length) __THROW __wur;
1060 # endif
1061
1062 #endif /* Use POSIX.1b || X/Open Unix || XPG6.  */
1063
1064
1065 #if (defined __USE_XOPEN_EXTENDED && !defined __USE_XOPEN2K) \
1066     || defined __USE_MISC
1067
1068 /* Set the end of accessible data space (aka "the break") to ADDR.
1069    Returns zero on success and -1 for errors (with errno set).  */
1070 extern int brk (void *__addr) __THROW __wur;
1071
1072 /* Increase or decrease the end of accessible data space by DELTA bytes.
1073    If successful, returns the address the previous end of data space
1074    (i.e. the beginning of the new space, if DELTA > 0);
1075    returns (void *) -1 for errors (with errno set).  */
1076 extern void *sbrk (intptr_t __delta) __THROW;
1077 #endif
1078
1079
1080 #ifdef __USE_MISC
1081 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
1082    This is completely system-dependent, and not often useful.
1083
1084    In Unix, `syscall' sets `errno' for all errors and most calls return -1
1085    for errors; in many systems you cannot pass arguments or get return
1086    values for all system calls (`pipe', `fork', and `getppid' typically
1087    among them).
1088
1089    In Mach, all system calls take normal arguments and always return an
1090    error code (zero for success).  */
1091 extern long int syscall (long int __sysno, ...) __THROW;
1092
1093 #endif  /* Use misc.  */
1094
1095
1096 #if (defined __USE_MISC || defined __USE_XOPEN_EXTENDED) && !defined F_LOCK
1097 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
1098    files consistent.  Some systems have them there and some here, and some
1099    software depends on the macros being defined without including both.  */
1100
1101 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
1102    LEN is always relative to the current file position.
1103    The CMD argument is one of the following.
1104
1105    This function is a cancellation point and therefore not marked with
1106    __THROW.  */
1107
1108 # define F_ULOCK 0      /* Unlock a previously locked region.  */
1109 # define F_LOCK  1      /* Lock a region for exclusive use.  */
1110 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
1111 # define F_TEST  3      /* Test a region for other processes locks.  */
1112
1113 # ifndef __USE_FILE_OFFSET64
1114 extern int lockf (int __fd, int __cmd, __off_t __len) __wur;
1115 # else
1116 #  ifdef __REDIRECT
1117 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len),
1118                        lockf64) __wur;
1119 #  else
1120 #   define lockf lockf64
1121 #  endif
1122 # endif
1123 # ifdef __USE_LARGEFILE64
1124 extern int lockf64 (int __fd, int __cmd, __off64_t __len) __wur;
1125 # endif
1126 #endif /* Use misc and F_LOCK not already defined.  */
1127
1128
1129 #ifdef __USE_GNU
1130
1131 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
1132    set to EINTR.  */
1133
1134 # define TEMP_FAILURE_RETRY(expression) \
1135   (__extension__                                                              \
1136     ({ long int __result;                                                     \
1137        do __result = (long int) (expression);                                 \
1138        while (__result == -1L && errno == EINTR);                             \
1139        __result; }))
1140
1141 /* Copy LENGTH bytes from INFD to OUTFD.  */
1142 ssize_t copy_file_range (int __infd, __off64_t *__pinoff,
1143                          int __outfd, __off64_t *__poutoff,
1144                          size_t __length, unsigned int __flags);
1145 #endif /* __USE_GNU */
1146
1147 #if defined __USE_POSIX199309 || defined __USE_UNIX98
1148 /* Synchronize at least the data part of a file with the underlying
1149    media.  */
1150 extern int fdatasync (int __fildes);
1151 #endif /* Use POSIX199309 */
1152
1153 #ifdef __USE_MISC
1154 /* One-way hash PHRASE, returning a string suitable for storage in the
1155    user database.  SALT selects the one-way function to use, and
1156    ensures that no two users' hashes are the same, even if they use
1157    the same passphrase.  The return value points to static storage
1158    which will be overwritten by the next call to crypt.  */
1159 extern char *crypt (const char *__key, const char *__salt)
1160      __THROW __nonnull ((1, 2));
1161 #endif
1162
1163 #ifdef  __USE_XOPEN
1164 /* Swab pairs bytes in the first N bytes of the area pointed to by
1165    FROM and copy the result to TO.  The value of TO must not be in the
1166    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
1167    is without partner.  */
1168 extern void swab (const void *__restrict __from, void *__restrict __to,
1169                   ssize_t __n) __THROW __nonnull ((1, 2))
1170     __attr_access ((__read_only__, 1, 3))
1171     __attr_access ((__write_only__, 2, 3));
1172 #endif
1173
1174
1175 /* Prior to Issue 6, the Single Unix Specification required these
1176    prototypes to appear in this header.  They are also found in
1177    <stdio.h>.  */
1178 #if defined __USE_XOPEN && !defined __USE_XOPEN2K
1179 /* Return the name of the controlling terminal.  */
1180 extern char *ctermid (char *__s) __THROW;
1181
1182 /* Return the name of the current user.  */
1183 extern char *cuserid (char *__s);
1184 #endif
1185
1186
1187 /* Unix98 requires this function to be declared here.  In other
1188    standards it is in <pthread.h>.  */
1189 #if defined __USE_UNIX98 && !defined __USE_XOPEN2K
1190 extern int pthread_atfork (void (*__prepare) (void),
1191                            void (*__parent) (void),
1192                            void (*__child) (void)) __THROW;
1193 #endif
1194
1195 #ifdef __USE_MISC
1196 /* Write LENGTH bytes of randomness starting at BUFFER.  Return 0 on
1197    success or -1 on error.  */
1198 int getentropy (void *__buffer, size_t __length) __wur
1199     __attr_access ((__write_only__, 1, 2));
1200 #endif
1201
1202 #ifdef __USE_GNU
1203 /* Close all file descriptors in the range FD up to MAX_FD.  The flag FLAGS
1204    are define by the CLOSE_RANGE prefix.  This function behaves like close
1205    on the range and gaps where the file descriptor is invalid or errors
1206    encountered while closing file descriptors are ignored.   Returns 0 on
1207    successor or -1 for failure (and sets errno accordingly).  */
1208 extern int close_range (unsigned int __fd, unsigned int __max_fd,
1209                         int __flags) __THROW;
1210 #endif
1211
1212 /* Define some macros helping to catch buffer overflows.  */
1213 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
1214 # include <bits/unistd.h>
1215 #endif
1216
1217 /* System-specific extensions.  */
1218 #include <bits/unistd_ext.h>
1219
1220 __END_DECLS
1221
1222 #endif /* unistd.h  */