posix/unistd.h

   1 /* Copyright (C) 1991-2002,2003,2004,2005 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 #endif
 264
 265
 266 /* Values for the WHENCE argument to lseek.  */
 267 #ifndef _STDIO_H                /* <stdio.h> has the same definitions.  */
 268 # define SEEK_SET       0       /* Seek from beginning of file.  */
 269 # define SEEK_CUR       1       /* Seek from current position.  */
 270 # define SEEK_END       2       /* Seek from end of file.  */
 271 #endif
 272
 273 #if defined __USE_BSD && !defined L_SET
 274 /* Old BSD names for the same constants; just for compatibility.  */
 275 # define L_SET          SEEK_SET
 276 # define L_INCR         SEEK_CUR
 277 # define L_XTND         SEEK_END
 278 #endif
 279
 280
 281 /* Move FD's file position to OFFSET bytes from the
 282    beginning of the file (if WHENCE is SEEK_SET),
 283    the current position (if WHENCE is SEEK_CUR),
 284    or the end of the file (if WHENCE is SEEK_END).
 285    Return the new file position.  */
 286 #ifndef __USE_FILE_OFFSET64
 287 extern __off_t lseek (int __fd, __off_t __offset, int __whence) __THROW;
 288 #else
 289 # ifdef __REDIRECT_NTH
 290 extern __off64_t __REDIRECT_NTH (lseek,
 291                                  (int __fd, __off64_t __offset, int __whence),
 292                                  lseek64);
 293 # else
 294 #  define lseek lseek64
 295 # endif
 296 #endif
 297 #ifdef __USE_LARGEFILE64
 298 extern __off64_t lseek64 (int __fd, __off64_t __offset, int __whence)
 299      __THROW;
 300 #endif
 301
 302 /* Close the file descriptor FD.
 303
 304    This function is a cancellation point and therefore not marked with
 305    __THROW.  */
 306 extern int close (int __fd);
 307
 308 /* Read NBYTES into BUF from FD.  Return the
 309    number read, -1 for errors or 0 for EOF.
 310
 311    This function is a cancellation point and therefore not marked with
 312    __THROW.  */
 313 extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur;
 314
 315 /* Write N bytes of BUF to FD.  Return the number written, or -1.
 316
 317    This function is a cancellation point and therefore not marked with
 318    __THROW.  */
 319 extern ssize_t write (int __fd, __const void *__buf, size_t __n) __wur;
 320
 321 #ifdef __USE_UNIX98
 322 # ifndef __USE_FILE_OFFSET64
 323 /* Read NBYTES into BUF from FD at the given position OFFSET without
 324    changing the file pointer.  Return the number read, -1 for errors
 325    or 0 for EOF.
 326
 327    This function is a cancellation point and therefore not marked with
 328    __THROW.  */
 329 extern ssize_t pread (int __fd, void *__buf, size_t __nbytes,
 330                       __off_t __offset) __wur;
 331
 332 /* Write N bytes of BUF to FD at the given position OFFSET without
 333    changing the file pointer.  Return the number written, or -1.
 334
 335    This function is a cancellation point and therefore not marked with
 336    __THROW.  */
 337 extern ssize_t pwrite (int __fd, __const void *__buf, size_t __n,
 338                        __off_t __offset) __wur;
 339 # else
 340 #  ifdef __REDIRECT
 341 extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes,
 342                                    __off64_t __offset),
 343                            pread64) __wur;
 344 extern ssize_t __REDIRECT (pwrite, (int __fd, __const void *__buf,
 345                                     size_t __nbytes, __off64_t __offset),
 346                            pwrite64) __wur;
 347 #  else
 348 #   define pread pread64
 349 #   define pwrite pwrite64
 350 #  endif
 351 # endif
 352
 353 # ifdef __USE_LARGEFILE64
 354 /* Read NBYTES into BUF from FD at the given position OFFSET without
 355    changing the file pointer.  Return the number read, -1 for errors
 356    or 0 for EOF.  */
 357 extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes,
 358                         __off64_t __offset) __wur;
 359 /* Write N bytes of BUF to FD at the given position OFFSET without
 360    changing the file pointer.  Return the number written, or -1.  */
 361 extern ssize_t pwrite64 (int __fd, __const void *__buf, size_t __n,
 362                          __off64_t __offset) __wur;
 363 # endif
 364 #endif
 365
 366 /* Create a one-way communication channel (pipe).
 367    If successful, two file descriptors are stored in PIPEDES;
 368    bytes written on PIPEDES[1] can be read from PIPEDES[0].
 369    Returns 0 if successful, -1 if not.  */
 370 extern int pipe (int __pipedes[2]) __THROW __wur;
 371
 372 /* Schedule an alarm.  In SECONDS seconds, the process will get a SIGALRM.
 373    If SECONDS is zero, any currently scheduled alarm will be cancelled.
 374    The function returns the number of seconds remaining until the last
 375    alarm scheduled would have signaled, or zero if there wasn't one.
 376    There is no return value to indicate an error, but you can set `errno'
 377    to 0 and check its value after calling `alarm', and this might tell you.
 378    The signal may come late due to processor scheduling.  */
 379 extern unsigned int alarm (unsigned int __seconds) __THROW;
 380
 381 /* Make the process sleep for SECONDS seconds, or until a signal arrives
 382    and is not ignored.  The function returns the number of seconds less
 383    than SECONDS which it actually slept (thus zero if it slept the full time).
 384    If a signal handler does a `longjmp' or modifies the handling of the
 385    SIGALRM signal while inside `sleep' call, the handling of the SIGALRM
 386    signal afterwards is undefined.  There is no return value to indicate
 387    error, but if `sleep' returns SECONDS, it probably didn't work.
 388
 389    This function is a cancellation point and therefore not marked with
 390    __THROW.  */
 391 extern unsigned int sleep (unsigned int __seconds);
 392
 393 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 394 /* Set an alarm to go off (generating a SIGALRM signal) in VALUE
 395    microseconds.  If INTERVAL is nonzero, when the alarm goes off, the
 396    timer is reset to go off every INTERVAL microseconds thereafter.
 397    Returns the number of microseconds remaining before the alarm.  */
 398 extern __useconds_t ualarm (__useconds_t __value, __useconds_t __interval)
 399      __THROW;
 400
 401 /* Sleep USECONDS microseconds, or until a signal arrives that is not blocked
 402    or ignored.
 403
 404    This function is a cancellation point and therefore not marked with
 405    __THROW.  */
 406 extern int usleep (__useconds_t __useconds);
 407 #endif
 408
 409
 410 /* Suspend the process until a signal arrives.
 411    This always returns -1 and sets `errno' to EINTR.
 412
 413    This function is a cancellation point and therefore not marked with
 414    __THROW.  */
 415 extern int pause (void);
 416
 417
 418 /* Change the owner and group of FILE.  */
 419 extern int chown (__const char *__file, __uid_t __owner, __gid_t __group)
 420      __THROW __nonnull ((1)) __wur;
 421
 422 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 423 /* Change the owner and group of the file that FD is open on.  */
 424 extern int fchown (int __fd, __uid_t __owner, __gid_t __group) __THROW __wur;
 425
 426
 427 /* Change owner and group of FILE, if it is a symbolic
 428    link the ownership of the symbolic link is changed.  */
 429 extern int lchown (__const char *__file, __uid_t __owner, __gid_t __group)
 430      __THROW __nonnull ((1)) __wur;
 431
 432 #endif /* Use BSD || X/Open Unix.  */
 433
 434 #ifdef __USE_GNU
 435 /* Change the owner and group of FILE relative to the directory FD is open
 436    on.  */
 437 extern int fchownat (int __fd, __const char *__file, __uid_t __owner,
 438                      __gid_t __group, int __flag)
 439      __THROW __nonnull ((2)) __wur;
 440 #endif /* Use GNU.  */
 441
 442 /* Change the process's working directory to PATH.  */
 443 extern int chdir (__const char *__path) __THROW __nonnull ((1)) __wur;
 444
 445 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 446 /* Change the process's working directory to the one FD is open on.  */
 447 extern int fchdir (int __fd) __THROW __wur;
 448 #endif
 449
 450 /* Get the pathname of the current working directory,
 451    and put it in SIZE bytes of BUF.  Returns NULL if the
 452    directory couldn't be determined or SIZE was too small.
 453    If successful, returns BUF.  In GNU, if BUF is NULL,
 454    an array is allocated with `malloc'; the array is SIZE
 455    bytes long, unless SIZE == 0, in which case it is as
 456    big as necessary.  */
 457 extern char *getcwd (char *__buf, size_t __size) __THROW __wur;
 458
 459 #ifdef  __USE_GNU
 460 /* Return a malloc'd string containing the current directory name.
 461    If the environment variable `PWD' is set, and its value is correct,
 462    that value is used.  */
 463 extern char *get_current_dir_name (void) __THROW;
 464 #endif
 465
 466 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 467 /* Put the absolute pathname of the current working directory in BUF.
 468    If successful, return BUF.  If not, put an error message in
 469    BUF and return NULL.  BUF should be at least PATH_MAX bytes long.  */
 470 extern char *getwd (char *__buf)
 471      __THROW __nonnull ((1)) __attribute_deprecated__ __wur;
 472 #endif
 473
 474
 475 /* Duplicate FD, returning a new file descriptor on the same file.  */
 476 extern int dup (int __fd) __THROW __wur;
 477
 478 /* Duplicate FD to FD2, closing FD2 and making it open on the same file.  */
 479 extern int dup2 (int __fd, int __fd2) __THROW;
 480
 481 /* NULL-terminated array of "NAME=VALUE" environment variables.  */
 482 extern char **__environ;
 483 #ifdef __USE_GNU
 484 extern char **environ;
 485 #endif
 486
 487
 488 /* Replace the current process, executing PATH with arguments ARGV and
 489    environment ENVP.  ARGV and ENVP are terminated by NULL pointers.  */
 490 extern int execve (__const char *__path, char *__const __argv[],
 491                    char *__const __envp[]) __THROW __nonnull ((1));
 492
 493 #ifdef __USE_GNU
 494 /* Execute the file FD refers to, overlaying the running program image.
 495    ARGV and ENVP are passed to the new program, as for `execve'.  */
 496 extern int fexecve (int __fd, char *__const __argv[], char *__const __envp[])
 497      __THROW;
 498 #endif
 499
 500
 501 /* Execute PATH with arguments ARGV and environment from `environ'.  */
 502 extern int execv (__const char *__path, char *__const __argv[])
 503      __THROW __nonnull ((1));
 504
 505 /* Execute PATH with all arguments after PATH until a NULL pointer,
 506    and the argument after that for environment.  */
 507 extern int execle (__const char *__path, __const char *__arg, ...)
 508      __THROW __nonnull ((1));
 509
 510 /* Execute PATH with all arguments after PATH until
 511    a NULL pointer and environment from `environ'.  */
 512 extern int execl (__const char *__path, __const char *__arg, ...)
 513      __THROW __nonnull ((1));
 514
 515 /* Execute FILE, searching in the `PATH' environment variable if it contains
 516    no slashes, with arguments ARGV and environment from `environ'.  */
 517 extern int execvp (__const char *__file, char *__const __argv[])
 518      __THROW __nonnull ((1));
 519
 520 /* Execute FILE, searching in the `PATH' environment variable if
 521    it contains no slashes, with all arguments after FILE until a
 522    NULL pointer and environment from `environ'.  */
 523 extern int execlp (__const char *__file, __const char *__arg, ...)
 524      __THROW __nonnull ((1));
 525
 526
 527 #if defined __USE_MISC || defined __USE_XOPEN
 528 /* Add INC to priority of the current process.  */
 529 extern int nice (int __inc) __THROW __wur;
 530 #endif
 531
 532
 533 /* Terminate program execution with the low-order 8 bits of STATUS.  */
 534 extern void _exit (int __status) __attribute__ ((__noreturn__));
 535
 536
 537 /* Get the `_PC_*' symbols for the NAME argument to `pathconf' and `fpathconf';
 538    the `_SC_*' symbols for the NAME argument to `sysconf';
 539    and the `_CS_*' symbols for the NAME argument to `confstr'.  */
 540 #include <bits/confname.h>
 541
 542 /* Get file-specific configuration information about PATH.  */
 543 extern long int pathconf (__const char *__path, int __name)
 544      __THROW __nonnull ((1));
 545
 546 /* Get file-specific configuration about descriptor FD.  */
 547 extern long int fpathconf (int __fd, int __name) __THROW;
 548
 549 /* Get the value of the system variable NAME.  */
 550 extern long int sysconf (int __name) __THROW __attribute__ ((__const__));
 551
 552 #ifdef  __USE_POSIX2
 553 /* Get the value of the string-valued system variable NAME.  */
 554 extern size_t confstr (int __name, char *__buf, size_t __len) __THROW;
 555 #endif
 556
 557
 558 /* Get the process ID of the calling process.  */
 559 extern __pid_t getpid (void) __THROW;
 560
 561 /* Get the process ID of the calling process's parent.  */
 562 extern __pid_t getppid (void) __THROW;
 563
 564 /* Get the process group ID of the calling process.
 565    This function is different on old BSD. */
 566 #ifndef __FAVOR_BSD
 567 extern __pid_t getpgrp (void) __THROW;
 568 #else
 569 # ifdef __REDIRECT_NTH
 570 extern __pid_t __REDIRECT_NTH (getpgrp, (__pid_t __pid), __getpgid);
 571 # else
 572 #  define getpgrp __getpgid
 573 # endif
 574 #endif
 575
 576 /* Get the process group ID of process PID.  */
 577 extern __pid_t __getpgid (__pid_t __pid) __THROW;
 578 #ifdef __USE_XOPEN_EXTENDED
 579 extern __pid_t getpgid (__pid_t __pid) __THROW;
 580 #endif
 581
 582
 583 /* Set the process group ID of the process matching PID to PGID.
 584    If PID is zero, the current process's process group ID is set.
 585    If PGID is zero, the process ID of the process is used.  */
 586 extern int setpgid (__pid_t __pid, __pid_t __pgid) __THROW;
 587
 588 #if defined __USE_SVID || defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 589 /* Both System V and BSD have `setpgrp' functions, but with different
 590    calling conventions.  The BSD function is the same as POSIX.1 `setpgid'
 591    (above).  The System V function takes no arguments and puts the calling
 592    process in its on group like `setpgid (0, 0)'.
 593
 594    New programs should always use `setpgid' instead.
 595
 596    The default in GNU is to provide the System V function.  The BSD
 597    function is available under -D_BSD_SOURCE.  */
 598
 599 # ifndef __FAVOR_BSD
 600
 601 /* Set the process group ID of the calling process to its own PID.
 602    This is exactly the same as `setpgid (0, 0)'.  */
 603 extern int setpgrp (void) __THROW;
 604
 605 # else
 606
 607 /* Another name for `setpgid' (above).  */
 608 #  ifdef __REDIRECT_NTH
 609 extern int __REDIRECT_NTH (setpgrp, (__pid_t __pid, __pid_t __pgrp), setpgid);
 610 #  else
 611 #   define setpgrp setpgid
 612 #  endif
 613
 614 # endif /* Favor BSD.  */
 615 #endif  /* Use SVID or BSD.  */
 616
 617 /* Create a new session with the calling process as its leader.
 618    The process group IDs of the session and the calling process
 619    are set to the process ID of the calling process, which is returned.  */
 620 extern __pid_t setsid (void) __THROW;
 621
 622 #ifdef __USE_XOPEN_EXTENDED
 623 /* Return the session ID of the given process.  */
 624 extern __pid_t getsid (__pid_t __pid) __THROW;
 625 #endif
 626
 627 /* Get the real user ID of the calling process.  */
 628 extern __uid_t getuid (void) __THROW;
 629
 630 /* Get the effective user ID of the calling process.  */
 631 extern __uid_t geteuid (void) __THROW;
 632
 633 /* Get the real group ID of the calling process.  */
 634 extern __gid_t getgid (void) __THROW;
 635
 636 /* Get the effective group ID of the calling process.  */
 637 extern __gid_t getegid (void) __THROW;
 638
 639 /* If SIZE is zero, return the number of supplementary groups
 640    the calling process is in.  Otherwise, fill in the group IDs
 641    of its supplementary groups in LIST and return the number written.  */
 642 extern int getgroups (int __size, __gid_t __list[]) __THROW __wur;
 643
 644 #ifdef  __USE_GNU
 645 /* Return nonzero iff the calling process is in group GID.  */
 646 extern int group_member (__gid_t __gid) __THROW;
 647 #endif
 648
 649 /* Set the user ID of the calling process to UID.
 650    If the calling process is the super-user, set the real
 651    and effective user IDs, and the saved set-user-ID to UID;
 652    if not, the effective user ID is set to UID.  */
 653 extern int setuid (__uid_t __uid) __THROW;
 654
 655 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 656 /* Set the real user ID of the calling process to RUID,
 657    and the effective user ID of the calling process to EUID.  */
 658 extern int setreuid (__uid_t __ruid, __uid_t __euid) __THROW;
 659 #endif
 660
 661 #if defined __USE_BSD || defined __USE_XOPEN2K
 662 /* Set the effective user ID of the calling process to UID.  */
 663 extern int seteuid (__uid_t __uid) __THROW;
 664 #endif /* Use BSD.  */
 665
 666 /* Set the group ID of the calling process to GID.
 667    If the calling process is the super-user, set the real
 668    and effective group IDs, and the saved set-group-ID to GID;
 669    if not, the effective group ID is set to GID.  */
 670 extern int setgid (__gid_t __gid) __THROW;
 671
 672 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 673 /* Set the real group ID of the calling process to RGID,
 674    and the effective group ID of the calling process to EGID.  */
 675 extern int setregid (__gid_t __rgid, __gid_t __egid) __THROW;
 676 #endif
 677
 678 #if defined __USE_BSD || defined __USE_XOPEN2K
 679 /* Set the effective group ID of the calling process to GID.  */
 680 extern int setegid (__gid_t __gid) __THROW;
 681 #endif /* Use BSD.  */
 682
 683 #ifdef __USE_GNU
 684 /* Fetch the effective user ID, real user ID, and saved-set user ID,
 685    of the calling process.  */
 686 extern int getresuid (__uid_t *__euid, __uid_t *__ruid, __uid_t *__suid)
 687      __THROW;
 688
 689 /* Fetch the effective group ID, real group ID, and saved-set group ID,
 690    of the calling process.  */
 691 extern int getresgid (__gid_t *__egid, __gid_t *__rgid, __gid_t *__sgid)
 692      __THROW;
 693
 694 /* Set the effective user ID, real user ID, and saved-set user ID,
 695    of the calling process to EUID, RUID, and SUID, respectively.  */
 696 extern int setresuid (__uid_t __euid, __uid_t __ruid, __uid_t __suid)
 697      __THROW;
 698
 699 /* Set the effective group ID, real group ID, and saved-set group ID,
 700    of the calling process to EGID, RGID, and SGID, respectively.  */
 701 extern int setresgid (__gid_t __egid, __gid_t __rgid, __gid_t __sgid)
 702      __THROW;
 703 #endif
 704
 705
 706 /* Clone the calling process, creating an exact copy.
 707    Return -1 for errors, 0 to the new process,
 708    and the process ID of the new process to the old process.  */
 709 extern __pid_t fork (void) __THROW;
 710
 711 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 712 /* Clone the calling process, but without copying the whole address space.
 713    The calling process is suspended until the new process exits or is
 714    replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
 715    and the process ID of the new process to the old process.  */
 716 extern __pid_t vfork (void) __THROW;
 717 #endif /* Use BSD. */
 718
 719
 720 /* Return the pathname of the terminal FD is open on, or NULL on errors.
 721    The returned storage is good only until the next call to this function.  */
 722 extern char *ttyname (int __fd) __THROW;
 723
 724 /* Store at most BUFLEN characters of the pathname of the terminal FD is
 725    open on in BUF.  Return 0 on success, otherwise an error number.  */
 726 extern int ttyname_r (int __fd, char *__buf, size_t __buflen)
 727      __THROW __nonnull ((2)) __wur;
 728
 729 /* Return 1 if FD is a valid descriptor associated
 730    with a terminal, zero if not.  */
 731 extern int isatty (int __fd) __THROW;
 732
 733 #if defined __USE_BSD \
 734     || (defined __USE_XOPEN_EXTENDED && !defined __USE_UNIX98)
 735 /* Return the index into the active-logins file (utmp) for
 736    the controlling terminal.  */
 737 extern int ttyslot (void) __THROW;
 738 #endif
 739
 740
 741 /* Make a link to FROM named TO.  */
 742 extern int link (__const char *__from, __const char *__to)
 743      __THROW __nonnull ((1, 2)) __wur;
 744
 745 #ifdef __USE_GNU
 746 /* Like link but relative paths in TO and FROM are interpreted relative
 747    to FROMFD and TOFD respectively.  */
 748 extern int linkat (int __fromfd, __const char *__from, int __tofd,
 749                    __const char *__to) __THROW __nonnull ((2, 4)) __wur;
 750 #endif
 751
 752 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 753 /* Make a symbolic link to FROM named TO.  */
 754 extern int symlink (__const char *__from, __const char *__to)
 755      __THROW __nonnull ((1, 2)) __wur;
 756
 757 /* Read the contents of the symbolic link PATH into no more than
 758    LEN bytes of BUF.  The contents are not null-terminated.
 759    Returns the number of characters read, or -1 for errors.  */
 760 extern int readlink (__const char *__restrict __path, char *__restrict __buf,
 761                      size_t __len) __THROW __nonnull ((1, 2)) __wur;
 762 #endif /* Use BSD.  */
 763
 764 #ifdef __USE_GNU
 765 /* Like symlink but a relative path in TO is interpreted relative to TOFD.  */
 766 extern int symlinkat (__const char *__from, int __tofd,
 767                       __const char *__to) __THROW __nonnull ((1, 3)) __wur;
 768
 769 /* Like readlink but a relative PATH is interpreted relative to FD.  */
 770 extern int readlinkat (int __fd, __const char *__restrict __path,
 771                        char *__restrict __buf, size_t __len)
 772      __THROW __nonnull ((2, 3)) __wur;
 773 #endif
 774
 775 /* Remove the link NAME.  */
 776 extern int unlink (__const char *__name) __THROW __nonnull ((1));
 777
 778 #ifdef __USE_GNU
 779 /* Remove the link NAME relative to FD.  */
 780 extern int unlinkat (int __fd, __const char *__name, int __flag)
 781      __THROW __nonnull ((2));
 782 #endif
 783
 784 /* Remove the directory PATH.  */
 785 extern int rmdir (__const char *__path) __THROW __nonnull ((1));
 786
 787
 788 /* Return the foreground process group ID of FD.  */
 789 extern __pid_t tcgetpgrp (int __fd) __THROW;
 790
 791 /* Set the foreground process group ID of FD set PGRP_ID.  */
 792 extern int tcsetpgrp (int __fd, __pid_t __pgrp_id) __THROW;
 793
 794
 795 /* Return the login name of the user.
 796
 797    This function is a possible cancellation points and therefore not
 798    marked with __THROW.  */
 799 extern char *getlogin (void);
 800 #if defined __USE_REENTRANT || defined __USE_UNIX98
 801 /* Return at most NAME_LEN characters of the login name of the user in NAME.
 802    If it cannot be determined or some other error occurred, return the error
 803    code.  Otherwise return 0.
 804
 805    This function is a possible cancellation points and therefore not
 806    marked with __THROW.  */
 807 extern int getlogin_r (char *__name, size_t __name_len) __nonnull ((1));
 808 #endif
 809
 810 #ifdef  __USE_BSD
 811 /* Set the login name returned by `getlogin'.  */
 812 extern int setlogin (__const char *__name) __THROW __nonnull ((1));
 813 #endif
 814
 815
 816 #ifdef  __USE_POSIX2
 817 /* Get definitions and prototypes for functions to process the
 818    arguments in ARGV (ARGC of them, minus the program name) for
 819    options given in OPTS.  */
 820 # define __need_getopt
 821 # include <getopt.h>
 822 #endif
 823
 824
 825 #if defined __USE_BSD || defined __USE_UNIX98
 826 /* Put the name of the current host in no more than LEN bytes of NAME.
 827    The result is null-terminated if LEN is large enough for the full
 828    name and the terminator.  */
 829 extern int gethostname (char *__name, size_t __len) __THROW __nonnull ((1));
 830 #endif
 831
 832
 833 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_UNIX98)
 834 /* Set the name of the current host to NAME, which is LEN bytes long.
 835    This call is restricted to the super-user.  */
 836 extern int sethostname (__const char *__name, size_t __len)
 837      __THROW __nonnull ((1)) __wur;
 838
 839 /* Set the current machine's Internet number to ID.
 840    This call is restricted to the super-user.  */
 841 extern int sethostid (long int __id) __THROW __wur;
 842
 843
 844 /* Get and set the NIS (aka YP) domain name, if any.
 845    Called just like `gethostname' and `sethostname'.
 846    The NIS domain name is usually the empty string when not using NIS.  */
 847 extern int getdomainname (char *__name, size_t __len)
 848      __THROW __nonnull ((1)) __wur;
 849 extern int setdomainname (__const char *__name, size_t __len)
 850      __THROW __nonnull ((1)) __wur;
 851
 852
 853 /* Revoke access permissions to all processes currently communicating
 854    with the control terminal, and then send a SIGHUP signal to the process
 855    group of the control terminal.  */
 856 extern int vhangup (void) __THROW;
 857
 858 /* Revoke the access of all descriptors currently open on FILE.  */
 859 extern int revoke (__const char *__file) __THROW __nonnull ((1)) __wur;
 860
 861
 862 /* Enable statistical profiling, writing samples of the PC into at most
 863    SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
 864    is enabled, the system examines the user PC and increments
 865    SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536].  If SCALE is zero,
 866    disable profiling.  Returns zero on success, -1 on error.  */
 867 extern int profil (unsigned short int *__sample_buffer, size_t __size,
 868                    size_t __offset, unsigned int __scale)
 869      __THROW __nonnull ((1));
 870
 871
 872 /* Turn accounting on if NAME is an existing file.  The system will then write
 873    a record for each process as it terminates, to this file.  If NAME is NULL,
 874    turn accounting off.  This call is restricted to the super-user.  */
 875 extern int acct (__const char *__name) __THROW;
 876
 877
 878 /* Successive calls return the shells listed in `/etc/shells'.  */
 879 extern char *getusershell (void) __THROW;
 880 extern void endusershell (void) __THROW; /* Discard cached info.  */
 881 extern void setusershell (void) __THROW; /* Rewind and re-read the file.  */
 882
 883
 884 /* Put the program in the background, and dissociate from the controlling
 885    terminal.  If NOCHDIR is zero, do `chdir ("/")'.  If NOCLOSE is zero,
 886    redirects stdin, stdout, and stderr to /dev/null.  */
 887 extern int daemon (int __nochdir, int __noclose) __THROW __wur;
 888 #endif /* Use BSD || X/Open.  */
 889
 890
 891 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
 892 /* Make PATH be the root directory (the starting point for absolute paths).
 893    This call is restricted to the super-user.  */
 894 extern int chroot (__const char *__path) __THROW __nonnull ((1)) __wur;
 895
 896 /* Prompt with PROMPT and read a string from the terminal without echoing.
 897    Uses /dev/tty if possible; otherwise stderr and stdin.  */
 898 extern char *getpass (__const char *__prompt) __nonnull ((1));
 899 #endif /* Use BSD || X/Open.  */
 900
 901
 902 #if defined __USE_BSD || defined __USE_XOPEN
 903 /* Make all changes done to FD actually appear on disk.
 904
 905    This function is a cancellation point and therefore not marked with
 906    __THROW.  */
 907 extern int fsync (int __fd);
 908 #endif /* Use BSD || X/Open.  */
 909
 910
 911 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 912
 913 /* Return identifier for the current host.  */
 914 extern long int gethostid (void);
 915
 916 /* Make all changes done to all files actually appear on disk.  */
 917 extern void sync (void) __THROW;
 918
 919
 920 /* Return the number of bytes in a page.  This is the system's page size,
 921    which is not necessarily the same as the hardware page size.  */
 922 extern int getpagesize (void)  __THROW __attribute__ ((__const__));
 923
 924
 925 /* Return the maximum number of file descriptors
 926    the current process could possibly have.  */
 927 extern int getdtablesize (void) __THROW;
 928
 929
 930 /* Truncate FILE to LENGTH bytes.  */
 931 # ifndef __USE_FILE_OFFSET64
 932 extern int truncate (__const char *__file, __off_t __length)
 933      __THROW __nonnull ((1)) __wur;
 934 # else
 935 #  ifdef __REDIRECT_NTH
 936 extern int __REDIRECT_NTH (truncate,
 937                            (__const char *__file, __off64_t __length),
 938                            truncate64) __nonnull ((1)) __wur;
 939 #  else
 940 #   define truncate truncate64
 941 #  endif
 942 # endif
 943 # ifdef __USE_LARGEFILE64
 944 extern int truncate64 (__const char *__file, __off64_t __length)
 945      __THROW __nonnull ((1)) __wur;
 946 # endif
 947
 948 #endif /* Use BSD || X/Open Unix.  */
 949
 950 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K
 951
 952 /* Truncate the file FD is open on to LENGTH bytes.  */
 953 # ifndef __USE_FILE_OFFSET64
 954 extern int ftruncate (int __fd, __off_t __length) __THROW __wur;
 955 # else
 956 #  ifdef __REDIRECT_NTH
 957 extern int __REDIRECT_NTH (ftruncate, (int __fd, __off64_t __length),
 958                            ftruncate64) __wur;
 959 #  else
 960 #   define ftruncate ftruncate64
 961 #  endif
 962 # endif
 963 # ifdef __USE_LARGEFILE64
 964 extern int ftruncate64 (int __fd, __off64_t __length) __THROW __wur;
 965 # endif
 966
 967 #endif /* Use BSD || X/Open Unix || POSIX 2003.  */
 968
 969
 970 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 971
 972 /* Set the end of accessible data space (aka "the break") to ADDR.
 973    Returns zero on success and -1 for errors (with errno set).  */
 974 extern int brk (void *__addr) __THROW __wur;
 975
 976 /* Increase or decrease the end of accessible data space by DELTA bytes.
 977    If successful, returns the address the previous end of data space
 978    (i.e. the beginning of the new space, if DELTA > 0);
 979    returns (void *) -1 for errors (with errno set).  */
 980 extern void *sbrk (intptr_t __delta) __THROW;
 981 #endif
 982
 983
 984 #ifdef __USE_MISC
 985 /* Invoke `system call' number SYSNO, passing it the remaining arguments.
 986    This is completely system-dependent, and not often useful.
 987
 988    In Unix, `syscall' sets `errno' for all errors and most calls return -1
 989    for errors; in many systems you cannot pass arguments or get return
 990    values for all system calls (`pipe', `fork', and `getppid' typically
 991    among them).
 992
 993    In Mach, all system calls take normal arguments and always return an
 994    error code (zero for success).  */
 995 extern long int syscall (long int __sysno, ...) __THROW;
 996
 997 #endif  /* Use misc.  */
 998
 999
1000 #if (defined __USE_MISC || defined __USE_XOPEN_EXTENDED) && !defined F_LOCK
1001 /* NOTE: These declarations also appear in <fcntl.h>; be sure to keep both
1002    files consistent.  Some systems have them there and some here, and some
1003    software depends on the macros being defined without including both.  */
1004
1005 /* `lockf' is a simpler interface to the locking facilities of `fcntl'.
1006    LEN is always relative to the current file position.
1007    The CMD argument is one of the following.
1008
1009    This function is a cancellation point and therefore not marked with
1010    __THROW.  */
1011
1012 # define F_ULOCK 0      /* Unlock a previously locked region.  */
1013 # define F_LOCK  1      /* Lock a region for exclusive use.  */
1014 # define F_TLOCK 2      /* Test and lock a region for exclusive use.  */
1015 # define F_TEST  3      /* Test a region for other processes locks.  */
1016
1017 # ifndef __USE_FILE_OFFSET64
1018 extern int lockf (int __fd, int __cmd, __off_t __len) __wur;
1019 # else
1020 #  ifdef __REDIRECT
1021 extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len),
1022                        lockf64) __wur;
1023 #  else
1024 #   define lockf lockf64
1025 #  endif
1026 # endif
1027 # ifdef __USE_LARGEFILE64
1028 extern int lockf64 (int __fd, int __cmd, __off64_t __len) __wur;
1029 # endif
1030 #endif /* Use misc and F_LOCK not already defined.  */
1031
1032
1033 #ifdef __USE_GNU
1034
1035 /* Evaluate EXPRESSION, and repeat as long as it returns -1 with `errno'
1036    set to EINTR.  */
1037
1038 # define TEMP_FAILURE_RETRY(expression) \
1039   (__extension__                                                              \
1040     ({ long int __result;                                                     \
1041        do __result = (long int) (expression);                                 \
1042        while (__result == -1L && errno == EINTR);                             \
1043        __result; }))
1044 #endif
1045
1046 #if defined __USE_POSIX199309 || defined __USE_UNIX98
1047 /* Synchronize at least the data part of a file with the underlying
1048    media.  */
1049 extern int fdatasync (int __fildes) __THROW;
1050 #endif /* Use POSIX199309 */
1051
1052
1053 /* XPG4.2 specifies that prototypes for the encryption functions must
1054    be defined here.  */
1055 #ifdef  __USE_XOPEN
1056 /* Encrypt at most 8 characters from KEY using salt to perturb DES.  */
1057 extern char *crypt (__const char *__key, __const char *__salt)
1058      __THROW __nonnull ((1, 2));
1059
1060 /* Encrypt data in BLOCK in place if EDFLAG is zero; otherwise decrypt
1061    block in place.  */
1062 extern void encrypt (char *__block, int __edflag) __THROW __nonnull ((1));
1063
1064
1065 /* Swab pairs bytes in the first N bytes of the area pointed to by
1066    FROM and copy the result to TO.  The value of TO must not be in the
1067    range [FROM - N + 1, FROM - 1].  If N is odd the first byte in FROM
1068    is without partner.  */
1069 extern void swab (__const void *__restrict __from, void *__restrict __to,
1070                   ssize_t __n) __THROW __nonnull ((1, 2));
1071 #endif
1072
1073
1074 /* The Single Unix specification demands this prototype to be here.
1075    It is also found in <stdio.h>.  */
1076 #ifdef __USE_XOPEN
1077 /* Return the name of the controlling terminal.  */
1078 extern char *ctermid (char *__s) __THROW __nonnull ((1));
1079 #endif
1080
1081
1082 /* Define some macros helping to catch buffer overflows.  */
1083 #if __USE_FORTIFY_LEVEL > 0 && !defined __cplusplus
1084 # include <bits/unistd.h>
1085 #endif
1086
1087 __END_DECLS
1088
1089 #endif /* unistd.h  */