posix/unistd.h

   1 /* Copyright (C) 1991-2002,2003,2004,2005,2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 /*
  20  *      POSIX Standard: 2.10 Symbolic Constants         <unistd.h>
  21  */
  22
  23 #ifndef _UNISTD_H
  24 #define _UNISTD_H       1
  25
  26 #include <features.h>
  27
  28 __BEGIN_DECLS
  29
  30 /* These may be used to determine what facilities are present at compile time.
  31    Their values can be obtained at run time from `sysconf'.  */
  32
  33 /* POSIX Standard approved as ISO/IEC 9945-1 as of December 2001.  */
  34 #define _POSIX_VERSION  200112L
  35
  36 /* These are not #ifdef __USE_POSIX2 because they are
  37    in the theoretically application-owned namespace.  */
  38
  39 /* The utilities on GNU systems also correspond to this version.  */
  40 #define _POSIX2_VERSION 200112L
  41
  42 /* If defined, the implementation supports the
  43    C Language Bindings Option.  */
  44 #define _POSIX2_C_BIND  200112L
  45
  46 /* If defined, the implementation supports the
  47    C Language Development Utilities Option.  */
  48 #define _POSIX2_C_DEV   200112L
  49
  50 /* If defined, the implementation supports the
  51    Software Development Utilities Option.  */
  52 #define _POSIX2_SW_DEV  200112L
  53
  54 /* If defined, the implementation supports the
  55    creation of locales with the localedef utility.  */
  56 #define _POSIX2_LOCALEDEF       200112L
  57
  58 /* X/Open version number to which the library conforms.  It is selectable.  */
  59 #ifdef __USE_UNIX98
  60 # define _XOPEN_VERSION 500
  61 #else
  62 # define _XOPEN_VERSION 4
  63 #endif
  64
  65 /* Commands and utilities from XPG4 are available.  */
  66 #define _XOPEN_XCU_VERSION      4
  67
  68 /* We are compatible with the old published standards as well.  */
  69 #define _XOPEN_XPG2     1
  70 #define _XOPEN_XPG3     1
  71 #define _XOPEN_XPG4     1
  72
  73 /* The X/Open Unix extensions are available.  */
  74 #define _XOPEN_UNIX     1
  75
  76 /* Encryption is present.  */
  77 #define _XOPEN_CRYPT    1
  78
  79 /* The enhanced internationalization capabilities according to XPG4.2
  80    are present.  */
  81 #define _XOPEN_ENH_I18N 1
  82
  83 /* The legacy interfaces are also available.  */
  84 #define _XOPEN_LEGACY   1
  85
  86
  87 /* Get values of POSIX options:
  88
  89    If these symbols are defined, the corresponding features are
  90    always available.  If not, they may be available sometimes.
  91    The current values can be obtained with `sysconf'.
  92
  93    _POSIX_JOB_CONTROL           Job control is supported.
  94    _POSIX_SAVED_IDS             Processes have a saved set-user-ID
  95                                 and a saved set-group-ID.
  96    _POSIX_REALTIME_SIGNALS      Real-time, queued signals are supported.
  97    _POSIX_PRIORITY_SCHEDULING   Priority scheduling is supported.
  98    _POSIX_TIMERS                POSIX.4 clocks and timers are supported.
  99    _POSIX_ASYNCHRONOUS_IO       Asynchronous I/O is supported.
 100    _POSIX_PRIORITIZED_IO        Prioritized asynchronous I/O is supported.
 101    _POSIX_SYNCHRONIZED_IO       Synchronizing file data is supported.
 102    _POSIX_FSYNC                 The fsync function is present.
 103    _POSIX_MAPPED_FILES          Mapping of files to memory is supported.
 104    _POSIX_MEMLOCK               Locking of all memory is supported.
 105    _POSIX_MEMLOCK_RANGE         Locking of ranges of memory is supported.
 106    _POSIX_MEMORY_PROTECTION     Setting of memory protections is supported.
 107    _POSIX_MESSAGE_PASSING       POSIX.4 message queues are supported.
 108    _POSIX_SEMAPHORES            POSIX.4 counting semaphores are supported.
 109    _POSIX_SHARED_MEMORY_OBJECTS POSIX.4 shared memory objects are supported.
 110    _POSIX_THREADS               POSIX.1c pthreads are supported.
 111    _POSIX_THREAD_ATTR_STACKADDR Thread stack address attribute option supported.
 112    _POSIX_THREAD_ATTR_STACKSIZE Thread stack size attribute option supported.
 113    _POSIX_THREAD_SAFE_FUNCTIONS Thread-safe functions are supported.
 114    _POSIX_THREAD_PRIORITY_SCHEDULING
 115                                 POSIX.1c thread execution scheduling supported.
 116    _POSIX_THREAD_PRIO_INHERIT   Thread priority inheritance option supported.
 117    _POSIX_THREAD_PRIO_PROTECT   Thread priority protection option supported.
 118    _POSIX_THREAD_PROCESS_SHARED Process-shared synchronization supported.
 119    _POSIX_PII                   Protocol-independent interfaces are supported.
 120    _POSIX_PII_XTI               XTI protocol-indep. interfaces are supported.
 121    _POSIX_PII_SOCKET            Socket protocol-indep. interfaces are supported.
 122    _POSIX_PII_INTERNET          Internet family of protocols supported.
 123    _POSIX_PII_INTERNET_STREAM   Connection-mode Internet protocol supported.
 124    _POSIX_PII_INTERNET_DGRAM    Connectionless Internet protocol supported.
 125    _POSIX_PII_OSI               ISO/OSI family of protocols supported.
 126    _POSIX_PII_OSI_COTS          Connection-mode ISO/OSI service supported.
 127    _POSIX_PII_OSI_CLTS          Connectionless ISO/OSI service supported.
 128    _POSIX_POLL                  Implementation supports `poll' function.
 129    _POSIX_SELECT                Implementation supports `select' and `pselect'.
 130
 131    _XOPEN_REALTIME              X/Open realtime support is available.
 132    _XOPEN_REALTIME_THREADS      X/Open realtime thread support is available.
 133    _XOPEN_SHM                   Shared memory interface according to XPG4.2.
 134
 135    _XBS5_ILP32_OFF32            Implementation provides environment with 32-bit
 136                                 int, long, pointer, and off_t types.
 137    _XBS5_ILP32_OFFBIG           Implementation provides environment with 32-bit
 138                                 int, long, and pointer and off_t with at least
 139                                 64 bits.
 140    _XBS5_LP64_OFF64             Implementation provides environment with 32-bit
 141                                 int, and 64-bit long, pointer, and off_t types.
 142    _XBS5_LPBIG_OFFBIG           Implementation provides environment with at
 143                                 least 32 bits int and long, pointer, and off_t
 144                                 with at least 64 bits.
 145
 146    If any of these symbols is defined as -1, the corresponding option is not
 147    true for any file.  If any is defined as other than -1, the corresponding
 148    option is true for all files.  If a symbol is not defined at all, the value
 149    for a specific file can be obtained from `pathconf' and `fpathconf'.
 150
 151    _POSIX_CHOWN_RESTRICTED      Only the super user can use `chown' to change
 152                                 the owner of a file.  `chown' can only be used
 153                                 to change the group ID of a file to a group of
 154                                 which the calling process is a member.
 155    _POSIX_NO_TRUNC              Pathname components longer than
 156                                 NAME_MAX generate an error.
 157    _POSIX_VDISABLE              If defined, if the value of an element of the
 158                                 `c_cc' member of `struct termios' is
 159                                 _POSIX_VDISABLE, no character will have the
 160                                 effect associated with that element.
 161    _POSIX_SYNC_IO               Synchronous I/O may be performed.
 162    _POSIX_ASYNC_IO              Asynchronous I/O may be performed.
 163    _POSIX_PRIO_IO               Prioritized Asynchronous I/O may be performed.
 164
 165    Support for the Large File Support interface is not generally available.
 166    If it is available the following constants are defined to one.
 167    _LFS64_LARGEFILE             Low-level I/O supports large files.
 168    _LFS64_STDIO                 Standard I/O supports large files.
 169    */
 170
 171 #include <bits/posix_opt.h>
 172
 173 /* Get the environment definitions from Unix98.  */
 174 #ifdef __USE_UNIX98
 175 # include <bits/environments.h>
 176 #endif
 177
 178 /* Standard file descriptors.  */
 179 #define STDIN_FILENO    0       /* Standard input.  */
 180 #define STDOUT_FILENO   1       /* Standard output.  */
 181 #define STDERR_FILENO   2       /* Standard error output.  */
 182
 183
 184 /* All functions that are not declared anywhere else.  */
 185
 186 #include <bits/types.h>
 187
 188 #ifndef __ssize_t_defined
 189 typedef __ssize_t ssize_t;
 190 # define __ssize_t_defined
 191 #endif
 192
 193 #define __need_size_t
 194 #define __need_NULL
 195 #include <stddef.h>
 196
 197 #if defined __USE_XOPEN || defined __USE_XOPEN2K
 198 /* The Single Unix specification says that some more types are
 199    available here.  */
 200 # ifndef __gid_t_defined
 201 typedef __gid_t gid_t;
 202 #  define __gid_t_defined
 203 # endif
 204
 205 # ifndef __uid_t_defined
 206 typedef __uid_t uid_t;
 207 #  define __uid_t_defined
 208 # endif
 209
 210 # ifndef __off_t_defined
 211 #  ifndef __USE_FILE_OFFSET64
 212 typedef __off_t off_t;
 213 #  else
 214 typedef __off64_t off_t;
 215 #  endif
 216 #  define __off_t_defined
 217 # endif
 218 # if defined __USE_LARGEFILE64 && !defined __off64_t_defined
 219 typedef __off64_t off64_t;
 220 #  define __off64_t_defined
 221 # endif
 222
 223 # ifndef __useconds_t_defined
 224 typedef __useconds_t useconds_t;
 225 #  define __useconds_t_defined
 226 # endif
 227
 228 # ifndef __pid_t_defined
 229 typedef __pid_t pid_t;
 230 #  define __pid_t_defined
 231 # endif
 232 #endif  /* X/Open */
 233
 234 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 235 # ifndef __intptr_t_defined
 236 typedef __intptr_t intptr_t;
 237 #  define __intptr_t_defined
 238 # endif
 239 #endif
 240
 241 #if defined __USE_BSD || defined __USE_XOPEN
 242 # ifndef __socklen_t_defined
 243 typedef __socklen_t socklen_t;
 244 #  define __socklen_t_defined
 245 # endif
 246 #endif
 247
 248 /* Values for the second argument to access.
 249    These may be OR'd together.  */
 250 #define R_OK    4               /* Test for read permission.  */
 251 #define W_OK    2               /* Test for write permission.  */
 252 #define X_OK    1               /* Test for execute permission.  */
 253 #define F_OK    0               /* Test for existence.  */
 254
 255 /* Test for access to NAME using the real UID and real GID.  */
 256 extern int access (__const char *__name, int __type) __THROW __nonnull ((1));
 257
 258 #ifdef __USE_GNU
 259 /* Test for access to NAME using the effective UID and GID
 260    (as normal file operations use).  */
 261 extern int euidaccess (__const char *__name, int __type)
 262      __THROW __nonnull ((1));
 263
 264 /* An alias for `euidaccess', used by some other systems.  */
 265 extern int eaccess (__const char *__name, int __type)
 266      __THROW __nonnull ((1));
 267 #endif
 268
 269 #ifdef __USE_ATFILE
 270 /* Test for access to FILE relative to the directory FD is open on.
 271    If AT_EACCESS is set in FLAG, then use effective IDs like `eaccess',
 272    otherwise use real IDs like `access'.  */
 273 extern int faccessat (int __fd, __const char *__file, int __type, int __flag)
 274      __THROW __nonnull ((2)) __wur;
 275 #endif /* Use GNU.  */
 276
 277
 278 /* Values for the WHENCE argument to lseek.  */
 279 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 280 # define SEEK_SET       0       /* Seek from beginning of file.  */
 281 # define SEEK_CUR       1       /* Seek from current position.  */
 282 # define SEEK_END       2       /* Seek from end of file.  */
 283 #endif
 284
 285 #if defined __USE_BSD && !defined L_SET
 286 /* Old BSD names for the same constants; just for compatibility.  */
 287 # define L_SET          SEEK_SET
 288 # define L_INCR         SEEK_CUR
 289 # define L_XTND         SEEK_END
 290 #endif
 291
 292
 293 /* Move FD's file position to OFFSET bytes from the
 294    beginning of the file (if WHENCE is SEEK_SET),
 295    the current position (if WHENCE is SEEK_CUR),
 296    or the end of the file (if WHENCE is SEEK_END).
 297    Return the new file position.  */
 298 #ifndef __USE_FILE_OFFSET64
 299 extern __off_t lseek (int __fd, __off_t __offset, int __whence) __THROW;
 300 #else
 301 # ifdef __REDIRECT_NTH
 302 extern __off64_t __REDIRECT_NTH (lseek,
 303                                  (int __fd, __off64_t __offset, int __whence),
 304                                  lseek64);
 305 # else
 306 #  define lseek lseek64
 307 # endif
 308 #endif
 309 #ifdef __USE_LARGEFILE64
 310 extern __off64_t lseek64 (int __fd, __off64_t __offset, int __whence)
 311      __THROW;
 312 #endif
 313
 314 /* Close the file descriptor FD.
 315
 316    This function is a cancellation point and therefore not marked with
 317    __THROW.  */
 318 extern int close (int __fd);
 319
 320 /* Read NBYTES into BUF from FD.  Return the
 321    number read, -1 for errors or 0 for EOF.
 322
 323    This function is a cancellation point and therefore not marked with
 324    __THROW.  */
 325 extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur;
 326
 327 /* Write N bytes of BUF to FD.  Return the number written, or -1.
 328
 329    This function is a cancellation point and therefore not marked with
 330    __THROW.  */
 331 extern ssize_t write (int __fd, __const void *__buf, size_t __n) __wur;
 332
 333 #ifdef __USE_UNIX98
 334 # ifndef __USE_FILE_OFFSET64
 335 /* Read NBYTES into BUF from FD at the given position OFFSET without
 336    changing the file pointer.  Return the number read, -1 for errors
 337    or 0 for EOF.
 338
 339    This function is a cancellation point and therefore not marked with
 340    __THROW.  */
 341 extern ssize_t pread (int __fd, void *__buf, size_t __nbytes,
 342                       __off_t __offset) __wur;
 343
 344 /* Write N bytes of BUF to FD at the given position OFFSET without
 345    changing the file pointer.  Return the number written, or -1.
 346
 347    This function is a cancellation point and therefore not marked with
 348    __THROW.  */
 349 extern ssize_t pwrite (int __fd, __const void *__buf, size_t __n,
 350                        __off_t __offset) __wur;
 351 # else
 352 #  ifdef __REDIRECT
 353 extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes,
 354                                    __off64_t __offset),
 355                            pread64) __wur;
 356 extern ssize_t __REDIRECT (pwrite, (int __fd, __const void *__buf,
 357                                     size_t __nbytes, __off64_t __offset),
 358                            pwrite64) __wur;
 359 #  else
 360 #   define pread pread64
 361 #   define pwrite pwrite64
 362 #  endif
 363 # endif
 364
 365 # ifdef __USE_LARGEFILE64
 366 /* Read NBYTES into BUF from FD at the given position OFFSET without
 367    changing the file pointer.  Return the number read, -1 for errors
 368    or 0 for EOF.  */
 369 extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes,
 370                         __off64_t __offset) __wur;
 371 /* Write N bytes of BUF to FD at the given position OFFSET without
 372    changing the file pointer.  Return the number written, or -1.  */
 373 extern ssize_t pwrite64 (int __fd, __const void *__buf, size_t __n,
 374                          __off64_t __offset) __wur;
 375 # endif
 376 #endif
 377
 378 /* Create a one-way communication channel (pipe).
 379    If successful, two file descriptors are stored in PIPEDES;
 380    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 381    Returns 0 if successful, -1 if not.  */
 382 extern int pipe (int __pipedes[2]) __THROW __wur;
 383
 384 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 385    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 386    The function returns the number of seconds remaining until the last
 387    alarm scheduled would have signaled, or zero if there wasn't one.
 388    There is no return value to indicate an error, but you can set `errno'
 389    to 0 and check its value after calling `alarm', and this might tell you.
 390    The signal may come late due to processor scheduling.  */
 391 extern unsigned int alarm (unsigned int __seconds) __THROW;
 392
 393 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 394    and is not ignored.  The function returns the number of seconds less
 395    than SECONDS which it actually slept (thus zero if it slept the full time).
 396    If a signal handler does a `longjmp' or modifies the handling of the
 397    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 398    signal afterwards is undefined.  There is no return value to indicate
 399    error, but if `sleep' returns SECONDS, it probably didn't work.
 400
 401    This function is a cancellation point and therefore not marked with
 402    __THROW.  */
 403 extern unsigned int sleep (unsigned int __seconds);
 404
 405 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 406 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 407    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 408    timer is reset to go off every INTERVAL microseconds thereafter.
 409    Returns the number of microseconds remaining before the alarm.  */
 410 extern __useconds_t ualarm (__useconds_t __value, __useconds_t __interval)
 411      __THROW;
 412
 413 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 414    or ignored.
 415
 416    This function is a cancellation point and therefore not marked with
 417    __THROW.  */
 418 extern int usleep (__useconds_t __useconds);
 419 #endif
 420
 421
 422 /* Suspend the process until a signal arrives.
 423    This always returns -1 and sets `errno' to EINTR.
 424
 425    This function is a cancellation point and therefore not marked with
 426    __THROW.  */
 427 extern int pause (void);
 428
 429
 430 /* Change the owner and group of FILE.  */
 431 extern int chown (__const char *__file, __uid_t __owner, __gid_t __group)
 432      __THROW __nonnull ((1)) __wur;
 433
 434 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 435 /* Change the owner and group of the file that FD is open on.  */
 436 extern int fchown (int __fd, __uid_t __owner, __gid_t __group) __THROW __wur;
 437
 438
 439 /* Change owner and group of FILE, if it is a symbolic
 440    link the ownership of the symbolic link is changed.  */
 441 extern int lchown (__const char *__file, __uid_t __owner, __gid_t __group)
 442      __THROW __nonnull ((1)) __wur;
 443
 444 #endif /* Use BSD || X/Open Unix.  */
 445
 446 #ifdef __USE_ATFILE
 447 /* Change the owner and group of FILE relative to the directory FD is open
 448    on.  */
 449 extern int fchownat (int __fd, __const char *__file, __uid_t __owner,
 450                      __gid_t __group, int __flag)
 451      __THROW __nonnull ((2)) __wur;
 452 #endif /* Use GNU.  */
 453
 454 /* Change the process's working directory to PATH.  */
 455 extern int chdir (__const char *__path) __THROW __nonnull ((1)) __wur;
 456
 457 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 458 /* Change the process's working directory to the one FD is open on.  */
 459 extern int fchdir (int __fd) __THROW __wur;
 460 #endif
 461
 462 /* Get the pathname of the current working directory,
 463    and put it in SIZE bytes of BUF.  Returns NULL if the
 464    directory couldn't be determined or SIZE was too small.
 465    If successful, returns BUF.  In GNU, if BUF is NULL,
 466    an array is allocated with `malloc'; the array is SIZE
 467    bytes long, unless SIZE == 0, in which case it is as
 468    big as necessary.  */
 469 extern char *getcwd (char *__buf, size_t __size) __THROW __wur;
 470
 471 #ifdef  __USE_GNU
 472 /* Return a malloc'd string containing the current directory name.
 473    If the environment variable `PWD' is set, and its value is correct,
 474    that value is used.  */
 475 extern char *get_current_dir_name (void) __THROW;
 476 #endif
 477
 478 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 479 /* Put the absolute pathname of the current working directory in BUF.
 480    If successful, return BUF.  If not, put an error message in
 481    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 482 extern char *getwd (char *__buf)
 483      __THROW __nonnull ((1)) __attribute_deprecated__ __wur;
 484 #endif
 485
 486
 487 /* Duplicate FD, returning a new file descriptor on the same file.  */
 488 extern int dup (int __fd) __THROW __wur;
 489
 490 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 491 extern int dup2 (int __fd, int __fd2) __THROW;
 492
 493 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 494 extern char **__environ;
 495 #ifdef __USE_GNU
 496 extern char **environ;
 497 #endif
 498
 499
 500 /* Replace the current process, executing PATH with arguments ARGV and
 501    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 502 extern int execve (__const char *__path, char *__const __argv[],
 503                    char *__const __envp[]) __THROW __nonnull ((1));
 504
 505 #ifdef __USE_GNU
 506 /* Execute the file FD refers to, overlaying the running program image.
 507    ARGV and ENVP are passed to the new program, as for `execve'.  */
 508 extern int fexecve (int __fd, char *__const __argv[], char *__const __envp[])
 509      __THROW;
 510 #endif
 511
 512
 513 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 514 extern int execv (__const char *__path, char *__const __argv[])
 515      __THROW __nonnull ((1));
 516
 517 /* Execute PATH with all arguments after PATH until a NULL pointer,
 518    and the argument after that for environment.  */
 519 extern int execle (__const char *__path, __const char *__arg, ...)
 520      __THROW __nonnull ((1));
 521
 522 /* Execute PATH with all arguments after PATH until
 523    a NULL pointer and environment from `environ'.  */
 524 extern int execl (__const char *__path, __const char *__arg, ...)
 525      __THROW __nonnull ((1));
 526
 527 /* Execute FILE, searching in the `PATH' environment variable if it contains
 528    no slashes, with arguments ARGV and environment from `environ'.  */
 529 extern int execvp (__const char *__file, char *__const __argv[])
 530      __THROW __nonnull ((1));
 531
 532 /* Execute FILE, searching in the `PATH' environment variable if
 533    it contains no slashes, with all arguments after FILE until a
 534    NULL pointer and environment from `environ'.  */
 535 extern int execlp (__const char *__file, __const char *__arg, ...)
 536      __THROW __nonnull ((1));
 537
 538
 539 #if defined __USE_MISC || defined __USE_XOPEN
 540 /* Add INC to priority of the current process.  */
 541 extern int nice (int __inc) __THROW __wur;
 542 #endif
 543
 544
 545 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 546 extern void _exit (int __status) __attribute__ ((__noreturn__));
 547
 548
 549 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 550    the `_SC_*' symbols for the NAME argument to `sysconf';
 551    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 552 #include <bits/confname.h>
 553
 554 /* Get file-specific configuration information about PATH.  */
 555 extern long int pathconf (__const char *__path, int __name)
 556      __THROW __nonnull ((1));
 557
 558 /* Get file-specific configuration about descriptor FD.  */
 559 extern long int fpathconf (int __fd, int __name) __THROW;
 560
 561 /* Get the value of the system variable NAME.  */
 562 extern long int sysconf (int __name) __THROW;
 563
 564 #ifdef  __USE_POSIX2
 565 /* Get the value of the string-valued system variable NAME.  */
 566 extern size_t confstr (int __name, char *__buf, size_t __len) __THROW;
 567 #endif
 568
 569
 570 /* Get the process ID of the calling process.  */
 571 extern __pid_t getpid (void) __THROW;
 572
 573 /* Get the process ID of the calling process's parent.  */
 574 extern __pid_t getppid (void) __THROW;
 575
 576 /* Get the process group ID of the calling process.
 577    This function is different on old BSD. */
 578 #ifndef __FAVOR_BSD
 579 extern __pid_t getpgrp (void) __THROW;
 580 #else
 581 # ifdef __REDIRECT_NTH
 582 extern __pid_t __REDIRECT_NTH (getpgrp, (__pid_t __pid), __getpgid);
 583 # else
 584 #  define getpgrp __getpgid
 585 # endif
 586 #endif
 587
 588 /* Get the process group ID of process PID.  */
 589 extern __pid_t __getpgid (__pid_t __pid) __THROW;
 590 #ifdef __USE_XOPEN_EXTENDED
 591 extern __pid_t getpgid (__pid_t __pid) __THROW;
 592 #endif
 593
 594
 595 /* Set the process group ID of the process matching PID to PGID.
 596    If PID is zero, the current process's process group ID is set.
 597    If PGID is zero, the process ID of the process is used.  */
 598 extern int setpgid (__pid_t __pid, __pid_t __pgid) __THROW;
 599
 600 #if defined __USE_SVID || defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 601 /* Both System V and BSD have `setpgrp' functions, but with different
 602    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 603    (above).  The System V function takes no arguments and puts the calling
 604    process in its on group like `setpgid (0, 0)'.
 605
 606    New programs should always use `setpgid' instead.
 607
 608    The default in GNU is to provide the System V function.  The BSD
 609    function is available under -D_BSD_SOURCE.  */
 610
 611 # ifndef __FAVOR_BSD
 612
 613 /* Set the process group ID of the calling process to its own PID.
 614    This is exactly the same as `setpgid (0, 0)'.  */
 615 extern int setpgrp (void) __THROW;
 616
 617 # else
 618
 619 /* Another name for `setpgid' (above).  */
 620 #  ifdef __REDIRECT_NTH
 621 extern int __REDIRECT_NTH (setpgrp, (__pid_t __pid, __pid_t __pgrp), setpgid);
 622 #  else
 623 #   define setpgrp setpgid
 624 #  endif
 625
 626 # endif /* Favor BSD.  */
 627 #endif  /* Use SVID or BSD.  */
 628
 629 /* Create a new session with the calling process as its leader.
 630    The process group IDs of the session and the calling process
 631    are set to the process ID of the calling process, which is returned.  */
 632 extern __pid_t setsid (void) __THROW;
 633
 634 #ifdef __USE_XOPEN_EXTENDED
 635 /* Return the session ID of the given process.  */
 636 extern __pid_t getsid (__pid_t __pid) __THROW;
 637 #endif
 638
 639 /* Get the real user ID of the calling process.  */
 640 extern __uid_t getuid (void) __THROW;
 641
 642 /* Get the effective user ID of the calling process.  */
 643 extern __uid_t geteuid (void) __THROW;
 644
 645 /* Get the real group ID of the calling process.  */
 646 extern __gid_t getgid (void) __THROW;
 647
 648 /* Get the effective group ID of the calling process.  */
 649 extern __gid_t getegid (void) __THROW;
 650
 651 /* If SIZE is zero, return the number of supplementary groups
 652    the calling process is in.  Otherwise, fill in the group IDs
 653    of its supplementary groups in LIST and return the number written.  */
 654 extern int getgroups (int __size, __gid_t __list[]) __THROW __wur;
 655
 656 #ifdef  __USE_GNU
 657 /* Return nonzero iff the calling process is in group GID.  */
 658 extern int group_member (__gid_t __gid) __THROW;
 659 #endif
 660
 661 /* Set the user ID of the calling process to UID.
 662    If the calling process is the super-user, set the real
 663    and effective user IDs, and the saved set-user-ID to UID;
 664    if not, the effective user ID is set to UID.  */
 665 extern int setuid (__uid_t __uid) __THROW;
 666
 667 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 668 /* Set the real user ID of the calling process to RUID,
 669    and the effective user ID of the calling process to EUID.  */
 670 extern int setreuid (__uid_t __ruid, __uid_t __euid) __THROW;
 671 #endif
 672
 673 #if defined __USE_BSD || defined __USE_XOPEN2K
 674 /* Set the effective user ID of the calling process to UID.  */
 675 extern int seteuid (__uid_t __uid) __THROW;
 676 #endif /* Use BSD.  */
 677
 678 /* Set the group ID of the calling process to GID.
 679    If the calling process is the super-user, set the real
 680    and effective group IDs, and the saved set-group-ID to GID;
 681    if not, the effective group ID is set to GID.  */
 682 extern int setgid (__gid_t __gid) __THROW;
 683
 684 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 685 /* Set the real group ID of the calling process to RGID,
 686    and the effective group ID of the calling process to EGID.  */
 687 extern int setregid (__gid_t __rgid, __gid_t __egid) __THROW;
 688 #endif
 689
 690 #if defined __USE_BSD || defined __USE_XOPEN2K
 691 /* Set the effective group ID of the calling process to GID.  */
 692 extern int setegid (__gid_t __gid) __THROW;
 693 #endif /* Use BSD.  */
 694
 695 #ifdef __USE_GNU
 696 /* Fetch the real user ID, effective user ID, and saved-set user ID,
 697    of the calling process.  */
 698 extern int getresuid (__uid_t *__ruid, __uid_t *__euid, __uid_t *__suid)
 699      __THROW;
 700
 701 /* Fetch the real group ID, effective group ID, and saved-set group ID,
 702    of the calling process.  */
 703 extern int getresgid (__gid_t *__rgid, __gid_t *__egid, __gid_t *__sgid)
 704      __THROW;
 705
 706 /* Set the real user ID, effective user ID, and saved-set user ID,
 707    of the calling process to RUID, EUID, and SUID, respectively.  */
 708 extern int setresuid (__uid_t __ruid, __uid_t __euid, __uid_t __suid)
 709      __THROW;
 710
 711 /* Set the real group ID, effective group ID, and saved-set group ID,
 712    of the calling process to RGID, EGID, and SGID, respectively.  */
 713 extern int setresgid (__gid_t __rgid, __gid_t __egid, __gid_t __sgid)
 714      __THROW;
 715 #endif
 716
 717
 718 /* Clone the calling process, creating an exact copy.
 719    Return -1 for errors, 0 to the new process,
 720    and the process ID of the new process to the old process.  */
 721 extern __pid_t fork (void) __THROW;
 722
 723 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 724 /* Clone the calling process, but without copying the whole address space.
 725    The calling process is suspended until the new process exits or is
 726    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 727    and the process ID of the new process to the old process.  */
 728 extern __pid_t vfork (void) __THROW;
 729 #endif /* Use BSD. */
 730
 731
 732 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 733    The returned storage is good only until the next call to this function.  */
 734 extern char *ttyname (int __fd) __THROW;
 735
 736 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 737    open on in BUF.  Return 0 on success, otherwise an error number.  */
 738 extern int ttyname_r (int __fd, char *__buf, size_t __buflen)
 739      __THROW __nonnull ((2)) __wur;
 740
 741 /* Return 1 if FD is a valid descriptor associated
 742    with a terminal, zero if not.  */
 743 extern int isatty (int __fd) __THROW;
 744
 745 #if defined __USE_BSD \
 746     || (defined __USE_XOPEN_EXTENDED && !defined __USE_UNIX98)
 747 /* Return the index into the active-logins file (utmp) for
 748    the controlling terminal.  */
 749 extern int ttyslot (void) __THROW;
 750 #endif
 751
 752
 753 /* Make a link to FROM named TO.  */
 754 extern int link (__const char *__from, __const char *__to)
 755      __THROW __nonnull ((1, 2)) __wur;
 756
 757 #ifdef __USE_ATFILE
 758 /* Like link but relative paths in TO and FROM are interpreted relative
 759    to FROMFD and TOFD respectively.  */
 760 extern int linkat (int __fromfd, __const char *__from, int __tofd,
 761                    __const char *__to, int __flags)
 762      __THROW __nonnull ((2, 4)) __wur;
 763 #endif
 764
 765 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 766 /* Make a symbolic link to FROM named TO.  */
 767 extern int symlink (__const char *__from, __const char *__to)
 768      __THROW __nonnull ((1, 2)) __wur;
 769
 770 /* Read the contents of the symbolic link PATH into no more than
 771    LEN bytes of BUF.  The contents are not null-terminated.
 772    Returns the number of characters read, or -1 for errors.  */
 773 extern ssize_t readlink (__const char *__restrict __path,
 774                          char *__restrict __buf, size_t __len)
 775      __THROW __nonnull ((1, 2)) __wur;
 776 #endif /* Use BSD.  */
 777
 778 #ifdef __USE_ATFILE
 779 /* Like symlink but a relative path in TO is interpreted relative to TOFD.  */
 780 extern int symlinkat (__const char *__from, int __tofd,
 781                       __const char *__to) __THROW __nonnull ((1, 3)) __wur;
 782
 783 /* Like readlink but a relative PATH is interpreted relative to FD.  */
 784 extern ssize_t readlinkat (int __fd, __const char *__restrict __path,
 785                            char *__restrict __buf, size_t __len)
 786      __THROW __nonnull ((2, 3)) __wur;
 787 #endif
 788
 789 /* Remove the link NAME.  */
 790 extern int unlink (__const char *__name) __THROW __nonnull ((1));
 791
 792 #ifdef __USE_ATFILE
 793 /* Remove the link NAME relative to FD.  */
 794 extern int unlinkat (int __fd, __const char *__name, int __flag)
 795      __THROW __nonnull ((2));
 796 #endif
 797
 798 /* Remove the directory PATH.  */
 799 extern int rmdir (__const char *__path) __THROW __nonnull ((1));
 800
 801
 802 /* Return the foreground process group ID of FD.  */
 803 extern __pid_t tcgetpgrp (int __fd) __THROW;
 804
 805 /* Set the foreground process group ID of FD set PGRP_ID.  */
 806 extern int tcsetpgrp (int __fd, __pid_t __pgrp_id) __THROW;
 807
 808
 809 /* Return the login name of the user.
 810
 811    This function is a possible cancellation points and therefore not
 812    marked with __THROW.  */
 813 extern char *getlogin (void);
 814 #if defined __USE_REENTRANT || defined __USE_POSIX199506
 815 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 816    If it cannot be determined or some other error occurred, return the error
 817    code.  Otherwise return 0.
 818
 819    This function is a possible cancellation points and therefore not
 820    marked with __THROW.  */
 821 extern int getlogin_r (char *__name, size_t __name_len) __nonnull ((1));
 822 #endif
 823
 824 #ifdef  __USE_BSD
 825 /* Set the login name returned by `getlogin'.  */
 826 extern int setlogin (__const char *__name) __THROW __nonnull ((1));
 827 #endif
 828
 829
 830 #ifdef  __USE_POSIX2
 831 /* Get definitions and prototypes for functions to process the
 832    arguments in ARGV (ARGC of them, minus the program name) for
 833    options given in OPTS.  */
 834 # define __need_getopt
 835 # include <getopt.h>
 836 #endif
 837
 838
 839 #if defined __USE_BSD || defined __USE_UNIX98
 840 /* Put the name of the current host in no more than LEN bytes of NAME.
 841    The result is null-terminated if LEN is large enough for the full
 842    name and the terminator.  */
 843 extern int gethostname (char *__name, size_t __len) __THROW __nonnull ((1));
 844 #endif
 845
 846
 847 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_UNIX98)
 848 /* Set the name of the current host to NAME, which is LEN bytes long.
 849    This call is restricted to the super-user.  */
 850 extern int sethostname (__const char *__name, size_t __len)
 851      __THROW __nonnull ((1)) __wur;
 852
 853 /* Set the current machine's Internet number to ID.
 854    This call is restricted to the super-user.  */
 855 extern int sethostid (long int __id) __THROW __wur;
 856
 857
 858 /* Get and set the NIS (aka YP) domain name, if any.
 859    Called just like `gethostname' and `sethostname'.
 860    The NIS domain name is usually the empty string when not using NIS.  */
 861 extern int getdomainname (char *__name, size_t __len)
 862      __THROW __nonnull ((1)) __wur;
 863 extern int setdomainname (__const char *__name, size_t __len)
 864      __THROW __nonnull ((1)) __wur;
 865
 866
 867 /* Revoke access permissions to all processes currently communicating
 868    with the control terminal, and then send a SIGHUP signal to the process
 869    group of the control terminal.  */
 870 extern int vhangup (void) __THROW;
 871
 872 /* Revoke the access of all descriptors currently open on FILE.  */
 873 extern int revoke (__const char *__file) __THROW __nonnull ((1)) __wur;
 874
 875
 876 /* Enable statistical profiling, writing samples of the PC into at most
 877    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 878    is enabled, the system examines the user PC and increments
 879    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 880    disable profiling.  Returns zero on success, -1 on error.  */
 881 extern int profil (unsigned short int *__sample_buffer, size_t __size,
 882                    size_t __offset, unsigned int __scale)
 883      __THROW __nonnull ((1));
 884
 885
 886 /* Turn accounting on if NAME is an existing file.  The system will then write
 887    a record for each process as it terminates, to this file.  If NAME is NULL,
 888    turn accounting off.  This call is restricted to the super-user.  */
 889 extern int acct (__const char *__name) __THROW;
 890
 891
 892 /* Successive calls return the shells listed in `/etc/shells'.  */
 893 extern char *getusershell (void) __THROW;
 894 extern void endusershell (void) __THROW; /* Discard cached info.  */
 895 extern void setusershell (void) __THROW; /* Rewind and re-read the file.  */
 896
 897
 898 /* Put the program in the background, and dissociate from the controlling
 899    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 900    redirects stdin, stdout, and stderr to /dev/null.  */
 901 extern int daemon (int __nochdir, int __noclose) __THROW __wur;
 902 #endif /* Use BSD || X/Open.  */
 903
 904
 905 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
 906 /* Make PATH be the root directory (the starting point for absolute paths).
 907    This call is restricted to the super-user.  */
 908 extern int chroot (__const char *__path) __THROW __nonnull ((1)) __wur;
 909
 910 /* Prompt with PROMPT and read a string from the terminal without echoing.
 911    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 912 extern char *getpass (__const char *__prompt) __nonnull ((1));
 913 #endif /* Use BSD || X/Open.  */
 914
 915
 916 #if defined __USE_BSD || defined __USE_XOPEN
 917 /* Make all changes done to FD actually appear on disk.
 918
 919    This function is a cancellation point and therefore not marked with
 920    __THROW.  */
 921 extern int fsync (int __fd);
 922 #endif /* Use BSD || X/Open.  */
 923
 924
 925 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 926
 927 /* Return identifier for the current host.  */
 928 extern long int gethostid (void);
 929
 930 /* Make all changes done to all files actually appear on disk.  */
 931 extern void sync (void) __THROW;
 932
 933
 934 /* Return the number of bytes in a page.  This is the system's page size,
 935    which is not necessarily the same as the hardware page size.  */
 936 extern int getpagesize (void)  __THROW __attribute__ ((__const__));
 937
 938
 939 /* Return the maximum number of file descriptors
 940    the current process could possibly have.  */
 941 extern int getdtablesize (void) __THROW;
 942
 943
 944 /* Truncate FILE to LENGTH bytes.  */
 945 # ifndef __USE_FILE_OFFSET64
 946 extern int truncate (__const char *__file, __off_t __length)
 947      __THROW __nonnull ((1)) __wur;
 948 # else
 949 #  ifdef __REDIRECT_NTH
 950 extern int __REDIRECT_NTH (truncate,
 951                            (__const char *__file, __off64_t __length),
 952                            truncate64) __nonnull ((1)) __wur;
 953 #  else
 954 #   define truncate truncate64
 955 #  endif
 956 # endif
 957 # ifdef __USE_LARGEFILE64
 958 extern int truncate64 (__const char *__file, __off64_t __length)
 959      __THROW __nonnull ((1)) __wur;
 960 # endif
 961
 962 #endif /* Use BSD || X/Open Unix.  */
 963
 964 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 965
 966 /* Truncate the file FD is open on to LENGTH bytes.  */
 967 # ifndef __USE_FILE_OFFSET64
 968 extern int ftruncate (int __fd, __off_t __length) __THROW __wur;
 969 # else
 970 #  ifdef __REDIRECT_NTH
 971 extern int __REDIRECT_NTH (ftruncate, (int __fd, __off64_t __length),
 972                            ftruncate64) __wur;
 973 #  else
 974 #   define ftruncate ftruncate64
 975 #  endif
 976 # endif
 977 # ifdef __USE_LARGEFILE64
 978 extern int ftruncate64 (int __fd, __off64_t __length) __THROW __wur;
 979 # endif
 980
 981 #endif /* Use BSD || X/Open Unix || POSIX 2003.  */
 982
 983
 984 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 985
 986 /* Set the end of accessible data space (aka "the break") to ADDR.
 987    Returns zero on success and -1 for errors (with errno set).  */
 988 extern int brk (void *__addr) __THROW __wur;
 989
 990 /* Increase or decrease the end of accessible data space by DELTA bytes.
 991    If successful, returns the address the previous end of data space
 992    (i.e. the beginning of the new space, if DELTA > 0);
 993    returns (void *) -1 for errors (with errno set).  */
 994 extern void *sbrk (intptr_t __delta) __THROW;
 995 #endif
 996
 997
 998 #ifdef __USE_MISC
 999 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
1000    This is completely system-dependent, and not often useful.
1001
1002    In Unix, `syscall' sets `errno' for all errors and most calls return -1
1003    for errors; in many systems you cannot pass arguments or get return
1004    values for all system calls (`pipe', `fork', and `getppid' typically
1005    among them).
1006
1007    In Mach, all system calls take normal arguments and always return an
1008    error code (zero for success).  */
1009 extern long int syscall (long int __sysno, ...) __THROW;
1010
1011 #endif  /* Use misc.  */
1012
1013
1014 #if (defined __USE_MISC || defined __USE_XOPEN_EXTENDED) && !defined F_LOCK
1015 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
1016    files consistent.  Some systems have them there and some here, and some
1017    software depends on the macros being defined without including both.  */
1018
1019 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
1020    LEN is always relative to the current file position.
1021    The CMD argument is one of the following.
1022
1023    This function is a cancellation point and therefore not marked with
1024    __THROW.  */
1025
1026 # define F_ULOCK 0      /* Unlock a previously locked region.  */
1027 # define F_LOCK  1      /* Lock a region for exclusive use.  */
1028 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
1029 # define F_TEST  3      /* Test a region for other processes locks.  */
1030
1031 # ifndef __USE_FILE_OFFSET64
1032 extern int lockf (int __fd, int __cmd, __off_t __len) __wur;
1033 # else
1034 #  ifdef __REDIRECT
1035 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len),
1036                        lockf64) __wur;
1037 #  else
1038 #   define lockf lockf64
1039 #  endif
1040 # endif
1041 # ifdef __USE_LARGEFILE64
1042 extern int lockf64 (int __fd, int __cmd, __off64_t __len) __wur;
1043 # endif
1044 #endif /* Use misc and F_LOCK not already defined.  */
1045
1046
1047 #ifdef __USE_GNU
1048
1049 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
1050    set to EINTR.  */
1051
1052 # define TEMP_FAILURE_RETRY(expression) \
1053   (__extension__                                                              \
1054     ({ long int __result;                                                     \
1055        do __result = (long int) (expression);                                 \
1056        while (__result == -1L && errno == EINTR);                             \
1057        __result; }))
1058 #endif
1059
1060 #if defined __USE_POSIX199309 || defined __USE_UNIX98
1061 /* Synchronize at least the data part of a file with the underlying
1062    media.  */
1063 extern int fdatasync (int __fildes) __THROW;
1064 #endif /* Use POSIX199309 */
1065
1066
1067 /* XPG4.2 specifies that prototypes for the encryption functions must
1068    be defined here.  */
1069 #ifdef  __USE_XOPEN
1070 /* Encrypt at most 8 characters from KEY using salt to perturb DES.  */
1071 extern char *crypt (__const char *__key, __const char *__salt)
1072      __THROW __nonnull ((1, 2));
1073
1074 /* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt
1075    block in place.  */
1076 extern void encrypt (char *__block, int __edflag) __THROW __nonnull ((1));
1077
1078
1079 /* Swab pairs bytes in the first N bytes of the area pointed to by
1080    FROM and copy the result to TO.  The value of TO must not be in the
1081    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
1082    is without partner.  */
1083 extern void swab (__const void *__restrict __from, void *__restrict __to,
1084                   ssize_t __n) __THROW __nonnull ((1, 2));
1085 #endif
1086
1087
1088 /* The Single Unix specification demands this prototype to be here.
1089    It is also found in <stdio.h>.  */
1090 #ifdef __USE_XOPEN
1091 /* Return the name of the controlling terminal.  */
1092 extern char *ctermid (char *__s) __THROW;
1093 #endif
1094
1095
1096 /* Define some macros helping to catch buffer overflows.  */
1097 #if __USE_FORTIFY_LEVEL > 0 && !defined __cplusplus
1098 # include <bits/unistd.h>
1099 #endif
1100
1101 __END_DECLS
1102
1103 #endif /* unistd.h  */