stdlib/stdlib.h

   1 /* Copyright (C) 1991,92,93,94,95,96,97,98 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 /*
  20  *      ISO C Standard: 4.10 GENERAL UTILITIES  <stdlib.h>
  21  */
  22
  23 #ifndef _STDLIB_H
  24 #define _STDLIB_H       1
  25
  26 #include <features.h>
  27
  28 /* Get size_t, wchar_t and NULL from <stddef.h>.  */
  29 #define __need_size_t
  30 #define __need_wchar_t
  31 #define __need_NULL
  32 #include <stddef.h>
  33
  34 __BEGIN_DECLS
  35
  36 /* Returned by `div'.  */
  37 typedef struct
  38   {
  39     int quot;                   /* Quotient.  */
  40     int rem;                    /* Remainder.  */
  41   } div_t;
  42
  43 /* Returned by `ldiv'.  */
  44 typedef struct
  45   {
  46     long int quot;              /* Quotient.  */
  47     long int rem;               /* Remainder.  */
  48   } ldiv_t;
  49
  50 #ifdef __USE_ISOC9X
  51 /* Returned by `lldiv'.  */
  52 typedef struct
  53   {
  54     long long int quot;         /* Quotient.  */
  55     long long int rem;          /* Remainder.  */
  56   } lldiv_t;
  57 #endif
  58
  59
  60 /* The largest number rand will return (same as INT_MAX).  */
  61 #define RAND_MAX        2147483647
  62
  63
  64 /* We define these the same for all machines.
  65    Changes from this to the outside world should be done in `_exit'.  */
  66 #define EXIT_FAILURE    1       /* Failing exit status.  */
  67 #define EXIT_SUCCESS    0       /* Successful exit status.  */
  68
  69
  70 /* Maximum length of a multibyte character in the current locale.  */
  71 #define MB_CUR_MAX      (__ctype_get_mb_cur_max ())
  72 extern int __ctype_get_mb_cur_max __P ((void));
  73
  74
  75 /* Convert a string to a floating-point number.  */
  76 extern double atof __P ((__const char *__nptr));
  77 /* Convert a string to an integer.  */
  78 extern int atoi __P ((__const char *__nptr));
  79 /* Convert a string to a long integer.  */
  80 extern long int atol __P ((__const char *__nptr));
  81
  82 #if defined __USE_ISOC9X || (defined __GNUC__ && defined __USE_MISC)
  83 /* These functions will part of the standard C library in ISO C 9X.  */
  84 extern long long int atoll __P ((__const char *__nptr));
  85 #endif
  86
  87 /* Convert a string to a floating-point number.  */
  88 extern double strtod __P ((__const char *__restrict __nptr,
  89                            char **__restrict __endptr));
  90
  91 #ifdef  __USE_ISOC9X
  92 /* Likewise for `float' and `long double' sizes of floating-point numbers.  */
  93 extern float strtof __P ((__const char *__restrict __nptr,
  94                           char **__restrict __endptr));
  95
  96 extern __long_double_t strtold __P ((__const char *__restrict __nptr,
  97                                      char **__restrict __endptr));
  98 #endif
  99
 100 /* Convert a string to a long integer.  */
 101 extern long int strtol __P ((__const char *__restrict __nptr,
 102                              char **__restrict __endptr, int __base));
 103 /* Convert a string to an unsigned long integer.  */
 104 extern unsigned long int strtoul __P ((__const char *__restrict __nptr,
 105                                        char **__restrict __endptr,
 106                                        int __base));
 107
 108 #if defined __GNUC__ && defined __USE_BSD
 109 /* Convert a string to a quadword integer.  */
 110 extern long long int strtoq __P ((__const char *__restrict __nptr,
 111                                   char **__restrict __endptr, int __base));
 112 /* Convert a string to an unsigned quadword integer.  */
 113 extern unsigned long long int strtouq __P ((__const char *__restrict __nptr,
 114                                             char **__restrict __endptr,
 115                                             int __base));
 116 #endif /* GCC and use BSD.  */
 117
 118 #if defined __USE_ISOC9X || (defined __GNUC__ && defined __USE_MISC)
 119 /* These functions will part of the standard C library in ISO C 9X.  */
 120
 121 /* Convert a string to a quadword integer.  */
 122 extern long long int strtoll __P ((__const char *__restrict __nptr,
 123                                    char **__restrict __endptr, int __base));
 124 /* Convert a string to an unsigned quadword integer.  */
 125 extern unsigned long long int strtoull __P ((__const char *__restrict __nptr,
 126                                              char **__restrict __endptr,
 127                                              int __base));
 128 #endif /* ISO C 9X or GCC and use MISC.  */
 129
 130
 131 #ifdef __USE_GNU
 132 /* The concept of one static locale per category is not very well
 133    thought out.  Many applications will need to process its data using
 134    information from several different locales.  Another application is
 135    the implementation of the internationalization handling in the
 136    upcoming ISO C++ standard library.  To support this another set of
 137    the functions using locale data exist which have an additional
 138    argument.
 139
 140    Attention: all these functions are *not* standardized in any form.
 141    This is a proof-of-concept implementation.  */
 142
 143 /* Structure for reentrant locale using functions.  This is an
 144    (almost) opaque type for the user level programs.  */
 145 # include <xlocale.h>
 146
 147 /* Special versions of the functions above which take the locale to
 148    use as an additional parameter.  */
 149 extern long int __strtol_l __P ((__const char *__restrict __nptr,
 150                                  char **__restrict __endptr, int __base,
 151                                  __locale_t __loc));
 152
 153 extern unsigned long int __strtoul_l __P ((__const char *__restrict __nptr,
 154                                            char **__restrict __endptr,
 155                                            int __base, __locale_t __loc));
 156
 157 extern long long int __strtoll_l __P ((__const char *__restrict __nptr,
 158                                        char **__restrict __endptr, int __base,
 159                                        __locale_t __loc));
 160
 161 extern unsigned long long int __strtoull_l __P ((__const char *__restrict
 162                                                  __nptr,
 163                                                  char **__restrict __endptr,
 164                                                  int __base,
 165                                                  __locale_t __loc));
 166
 167 extern double __strtod_l __P ((__const char *__restrict __nptr,
 168                                char **__restrict __endptr, __locale_t __loc));
 169
 170 extern float __strtof_l __P ((__const char *__restrict __nptr,
 171                               char **__restrict __endptr, __locale_t __loc));
 172
 173 extern __long_double_t __strtold_l __P ((__const char *__restrict __nptr,
 174                                          char **__restrict __endptr,
 175                                          __locale_t __loc));
 176 #endif /* GNU */
 177
 178
 179 /* The internal entry points for `strtoX' take an extra flag argument
 180    saying whether or not to parse locale-dependent number grouping.  */
 181
 182 extern double __strtod_internal __P ((__const char *__restrict __nptr,
 183                                       char **__restrict __endptr,
 184                                       int __group));
 185 extern float __strtof_internal __P ((__const char *__restrict __nptr,
 186                                      char **__restrict __endptr, int __group));
 187 extern __long_double_t __strtold_internal __P ((__const char *
 188                                                 __restrict __nptr,
 189                                                 char **__restrict __endptr,
 190                                                 int __group));
 191 #ifndef __strtol_internal_defined
 192 extern long int __strtol_internal __P ((__const char *__restrict __nptr,
 193                                         char **__restrict __endptr,
 194                                         int __base, int __group));
 195 # define __strtol_internal_defined      1
 196 #endif
 197 #ifndef __strtoul_internal_defined
 198 extern unsigned long int __strtoul_internal __P ((__const char *
 199                                                   __restrict __nptr,
 200                                                   char **__restrict __endptr,
 201                                                   int __base, int __group));
 202 # define __strtoul_internal_defined     1
 203 #endif
 204 #if defined __GNUC__ || defined __USE_ISOC9X
 205 # ifndef __strtoll_internal_defined
 206 extern long long int __strtoll_internal __P ((__const char *__restrict __nptr,
 207                                               char **__restrict __endptr,
 208                                               int __base, int __group));
 209 #  define __strtoll_internal_defined    1
 210 # endif
 211 # ifndef __strtoull_internal_defined
 212 extern unsigned long long int __strtoull_internal __P ((__const char *
 213                                                         __restrict __nptr,
 214                                                         char **
 215                                                         __restrict __endptr,
 216                                                         int __base,
 217                                                         int __group));
 218 #  define __strtoull_internal_defined   1
 219 # endif
 220 #endif /* GCC */
 221
 222 #if defined __OPTIMIZE__ && !defined __OPTIMIZE_SIZE__ \
 223     && defined __USE_EXTERN_INLINES
 224 /* Define inline functions which call the internal entry points.  */
 225
 226 extern __inline double
 227 strtod (__const char *__restrict __nptr, char **__restrict __endptr)
 228 {
 229   return __strtod_internal (__nptr, __endptr, 0);
 230 }
 231 extern __inline long int
 232 strtol (__const char *__restrict __nptr, char **__restrict __endptr,
 233         int __base)
 234 {
 235   return __strtol_internal (__nptr, __endptr, __base, 0);
 236 }
 237 extern __inline unsigned long int
 238 strtoul (__const char *__restrict __nptr, char **__restrict __endptr,
 239          int __base)
 240 {
 241   return __strtoul_internal (__nptr, __endptr, __base, 0);
 242 }
 243
 244 # ifdef __USE_ISOC9X
 245 extern __inline float
 246 strtof (__const char *__restrict __nptr, char **__restrict __endptr)
 247 {
 248   return __strtof_internal (__nptr, __endptr, 0);
 249 }
 250 extern __inline __long_double_t
 251 strtold (__const char *__restrict __nptr, char **__restrict __endptr)
 252 {
 253   return __strtold_internal (__nptr, __endptr, 0);
 254 }
 255 # endif
 256
 257 # ifdef __USE_BSD
 258 extern __inline long long int
 259 strtoq (__const char *__restrict __nptr, char **__restrict __endptr,
 260         int __base)
 261 {
 262   return __strtoll_internal (__nptr, __endptr, __base, 0);
 263 }
 264 extern __inline unsigned long long int
 265 strtouq (__const char *__restrict __nptr, char **__restrict __endptr,
 266          int __base)
 267 {
 268   return __strtoull_internal (__nptr, __endptr, __base, 0);
 269 }
 270 # endif
 271
 272 # if defined __USE_MISC || defined __USE_ISOC9X
 273 extern __inline long long int
 274 strtoll (__const char *__restrict __nptr, char **__restrict __endptr,
 275          int __base)
 276 {
 277   return __strtoll_internal (__nptr, __endptr, __base, 0);
 278 }
 279 extern __inline unsigned long long int
 280 strtoull (__const char * __restrict __nptr, char **__restrict __endptr,
 281           int __base)
 282 {
 283   return __strtoull_internal (__nptr, __endptr, __base, 0);
 284 }
 285 # endif
 286
 287 extern __inline double
 288 atof (__const char *__nptr)
 289 {
 290   return strtod (__nptr, (char **) NULL);
 291 }
 292 extern __inline int
 293 atoi (__const char *__nptr)
 294 {
 295   return (int) strtol (__nptr, (char **) NULL, 10);
 296 }
 297 extern __inline long int
 298 atol (__const char *__nptr)
 299 {
 300   return strtol (__nptr, (char **) NULL, 10);
 301 }
 302
 303 # if defined __USE_MISC || defined __USE_ISOC9X
 304 extern __inline long long int
 305 atoll (__const char *__nptr)
 306 {
 307   return strtoll (__nptr, (char **) NULL, 10);
 308 }
 309 # endif
 310 #endif /* Optimizing and Inlining.  */
 311
 312
 313 #if defined __USE_SVID || defined __USE_XOPEN_EXTENDED
 314 /* Convert N to base 64 using the digits "./0-9A-Za-z", least-significant
 315    digit first.  Returns a pointer to static storage overwritten by the
 316    next call.  */
 317 extern char *l64a __P ((long int __n));
 318
 319 /* Read a number from a string S in base 64 as above.  */
 320 extern long int a64l __P ((__const char *__s));
 321
 322
 323 # include <sys/types.h> /* we need int32_t... */
 324
 325 /* These are the functions that actually do things.  The `random', `srandom',
 326    `initstate' and `setstate' functions are those from BSD Unices.
 327    The `rand' and `srand' functions are required by the ANSI standard.
 328    We provide both interfaces to the same random number generator.  */
 329 /* Return a random long integer between 0 and RAND_MAX inclusive.  */
 330 extern int32_t random __P ((void));
 331
 332 /* Seed the random number generator with the given number.  */
 333 extern void srandom __P ((unsigned int __seed));
 334
 335 /* Initialize the random number generator to use state buffer STATEBUF,
 336    of length STATELEN, and seed it with SEED.  Optimal lengths are 8, 16,
 337    32, 64, 128 and 256, the bigger the better; values less than 8 will
 338    cause an error and values greater than 256 will be rounded down.  */
 339 extern __ptr_t initstate __P ((unsigned int __seed, __ptr_t __statebuf,
 340                                size_t __statelen));
 341
 342 /* Switch the random number generator to state buffer STATEBUF,
 343    which should have been previously initialized by `initstate'.  */
 344 extern __ptr_t setstate __P ((__ptr_t __statebuf));
 345
 346
 347 # ifdef __USE_MISC
 348 /* Reentrant versions of the `random' family of functions.
 349    These functions all use the following data structure to contain
 350    state, rather than global state variables.  */
 351
 352 struct random_data
 353   {
 354     int32_t *fptr;              /* Front pointer.  */
 355     int32_t *rptr;              /* Rear pointer.  */
 356     int32_t *state;             /* Array of state values.  */
 357     int rand_type;              /* Type of random number generator.  */
 358     int rand_deg;               /* Degree of random number generator.  */
 359     int rand_sep;               /* Distance between front and rear.  */
 360     int32_t *end_ptr;           /* Pointer behind state table.  */
 361   };
 362
 363 extern int random_r __P ((struct random_data *__buf, int32_t *__result));
 364
 365 extern int srandom_r __P ((unsigned int __seed, struct random_data *__buf));
 366
 367 extern int initstate_r __P ((unsigned int __seed, __ptr_t __statebuf,
 368                              size_t __statelen, struct random_data *__buf));
 369
 370 extern int setstate_r __P ((__ptr_t __statebuf, struct random_data *__buf));
 371 # endif /* Use misc.  */
 372 #endif  /* Use SVID || extended X/Open.  */
 373
 374
 375 /* Return a random integer between 0 and RAND_MAX inclusive.  */
 376 extern int rand __P ((void));
 377 /* Seed the random number generator with the given number.  */
 378 extern void srand __P ((unsigned int __seed));
 379
 380 #ifdef __USE_POSIX
 381 /* Reentrant interface according to POSIX.1.  */
 382 extern int rand_r __P ((unsigned int *__seed));
 383 #endif
 384
 385
 386 #if defined __USE_SVID || defined __USE_XOPEN
 387 /* System V style 48-bit random number generator functions.  */
 388
 389 /* Return non-negative, double-precision floating-point value in [0.0,1.0).  */
 390 extern double drand48 __P ((void));
 391 extern double erand48 __P ((unsigned short int __xsubi[3]));
 392
 393 /* Return non-negative, long integer in [0,2^31).  */
 394 extern long int lrand48 __P ((void));
 395 extern long int nrand48 __P ((unsigned short int __xsubi[3]));
 396
 397 /* Return signed, long integers in [-2^31,2^31).  */
 398 extern long int mrand48 __P ((void));
 399 extern long int jrand48 __P ((unsigned short int __xsubi[3]));
 400
 401 /* Seed random number generator.  */
 402 extern void srand48 __P ((long int __seedval));
 403 extern unsigned short int *seed48 __P ((unsigned short int __seed16v[3]));
 404 extern void lcong48 __P ((unsigned short int __param[7]));
 405
 406 /* Data structure for communication with thread safe versions.  */
 407 struct drand48_data
 408   {
 409     unsigned short int x[3];    /* Current state.  */
 410     unsigned short int a[3];    /* Factor in congruential formula.  */
 411     unsigned short int c;       /* Additive const. in congruential formula.  */
 412     unsigned short int old_x[3]; /* Old state.  */
 413     int init;                   /* Flag for initializing.  */
 414   };
 415
 416 # ifdef __USE_MISC
 417 /* Return non-negative, double-precision floating-point value in [0.0,1.0).  */
 418 extern int drand48_r __P ((struct drand48_data *__buffer, double *__result));
 419 extern int erand48_r __P ((unsigned short int __xsubi[3],
 420                            struct drand48_data *__buffer, double *__result));
 421
 422 /* Return non-negative, long integer in [0,2^31).  */
 423 extern int lrand48_r __P ((struct drand48_data *__buffer, long int *__result));
 424 extern int nrand48_r __P ((unsigned short int __xsubi[3],
 425                            struct drand48_data *__buffer, long int *__result));
 426
 427 /* Return signed, long integers in [-2^31,2^31).  */
 428 extern int mrand48_r __P ((struct drand48_data *__buffer, long int *__result));
 429 extern int jrand48_r __P ((unsigned short int __xsubi[3],
 430                            struct drand48_data *__buffer, long int *__result));
 431
 432 /* Seed random number generator.  */
 433 extern int srand48_r __P ((long int __seedval, struct drand48_data *__buffer));
 434
 435 extern int seed48_r __P ((unsigned short int __seed16v[3],
 436                           struct drand48_data *__buffer));
 437
 438 extern int lcong48_r __P ((unsigned short int __param[7],
 439                            struct drand48_data *__buffer));
 440 # endif /* Use misc.  */
 441 #endif  /* Use SVID or X/Open.  */
 442
 443
 444 /* Allocate SIZE bytes of memory.  */
 445 extern __ptr_t malloc __P ((size_t __size));
 446 /* Re-allocate the previously allocated block
 447    in __ptr_t, making the new block SIZE bytes long.  */
 448 extern __ptr_t realloc __P ((__ptr_t __ptr, size_t __size));
 449 /* Allocate NMEMB elements of SIZE bytes each, all initialized to 0.  */
 450 extern __ptr_t calloc __P ((size_t __nmemb, size_t __size));
 451 /* Free a block allocated by `malloc', `realloc' or `calloc'.  */
 452 extern void free __P ((__ptr_t __ptr));
 453
 454 #ifdef  __USE_MISC
 455 /* Free a block.  An alias for `free'.  (Sun Unices).  */
 456 extern void cfree __P ((__ptr_t __ptr));
 457 #endif /* Use misc.  */
 458
 459 #if defined __USE_GNU || defined __USE_BSD || defined __USE_MISC
 460 # include <alloca.h>
 461 #endif /* Use GNU, BSD, or misc.  */
 462
 463 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 464 /* Allocate SIZE bytes on a page boundary.  The storage cannot be freed.  */
 465 extern __ptr_t valloc __P ((size_t __size));
 466 #endif
 467
 468
 469 /* Abort execution and generate a core-dump.  */
 470 extern void abort __P ((void)) __attribute__ ((__noreturn__));
 471
 472
 473 /* Register a function to be called when `exit' is called.  */
 474 extern int atexit __P ((void (*__func) (void)));
 475
 476 #ifdef  __USE_MISC
 477 /* Register a function to be called with the status
 478    given to `exit' and the given argument.  */
 479 extern int __on_exit __P ((void (*__func) (int __status, __ptr_t __arg),
 480                            __ptr_t __arg));
 481 extern int on_exit __P ((void (*__func) (int __status, __ptr_t __arg),
 482                          __ptr_t __arg));
 483 #endif
 484
 485 /* Call all functions registered with `atexit' and `on_exit',
 486    in the reverse of the order in which they were registered
 487    perform stdio cleanup, and terminate program execution with STATUS.  */
 488 extern void exit __P ((int __status)) __attribute__ ((__noreturn__));
 489
 490
 491 /* Return the value of envariable NAME, or NULL if it doesn't exist.  */
 492 extern char *getenv __P ((__const char *__name));
 493
 494 /* This function is similar to the above but returns NULL if the
 495    programs is running with SUID or SGID enabled.  */
 496 extern char *__secure_getenv __P ((__const char *__name));
 497
 498 #if defined __USE_SVID || defined __USE_XOPEN
 499 /* The SVID says this is in <stdio.h>, but this seems a better place.   */
 500 /* Put STRING, which is of the form "NAME=VALUE", in the environment.
 501    If there is no `=', remove NAME from the environment.  */
 502 extern int putenv __P ((__const char *__string));
 503 #endif
 504
 505 #ifdef  __USE_BSD
 506 /* Set NAME to VALUE in the environment.
 507    If REPLACE is nonzero, overwrite an existing value.  */
 508 extern int setenv __P ((__const char *__name, __const char *__value,
 509                         int __replace));
 510
 511 /* Remove the variable NAME from the environment.  */
 512 extern void unsetenv __P ((__const char *__name));
 513 #endif
 514
 515 #ifdef  __USE_MISC
 516 /* The `clearenv' was planned to be added to POSIX.1 but probably
 517    never made it.  Nevertheless the POSIX.9 standard (POSIX bindings
 518    for Fortran 77) requires this function.  */
 519 extern int clearenv __P ((void));
 520 #endif
 521
 522
 523 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
 524 /* Generate a unique temporary file name from TEMPLATE.
 525    The last six characters of TEMPLATE must be "XXXXXX";
 526    they are replaced with a string that makes the file name unique.
 527    Returns TEMPLATE, or a null pointer if it cannot get a unique file name.  */
 528 extern char *mktemp __P ((char *__template));
 529
 530 /* Generate a unique temporary file name from TEMPLATE.
 531    The last six characters of TEMPLATE must be "XXXXXX";
 532    they are replaced with a string that makes the filename unique.
 533    Returns a file descriptor open on the file for reading and writing,
 534    or -1 if it cannot create a uniquely-named file.  */
 535 extern int mkstemp __P ((char *__template));
 536 #endif
 537
 538
 539 /* Execute the given line as a shell command.  */
 540 extern int system __P ((__const char *__command));
 541
 542
 543 #ifdef  __USE_GNU
 544 /* Return a malloc'd string containing the canonical absolute name of the
 545    named file.  The last file name component need not exist, and may be a
 546    symlink to a nonexistent file.  */
 547 extern char *canonicalize_file_name __P ((__const char *__name));
 548 #endif
 549
 550 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 551 /* Return the canonical absolute name of file NAME.  The last file name
 552    component need not exist, and may be a symlink to a nonexistent file.
 553    If RESOLVED is null, the result is malloc'd; otherwise, if the canonical
 554    name is PATH_MAX chars or more, returns null with `errno' set to
 555    ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars, returns the
 556    name in RESOLVED.  */
 557 extern char *realpath __P ((__const char *__name, char *__resolved));
 558 #endif
 559
 560
 561 /* Shorthand for type of comparison functions.  */
 562 #ifndef __COMPAR_FN_T
 563 # define __COMPAR_FN_T
 564 typedef int (*__compar_fn_t) __PMT ((__const __ptr_t, __const __ptr_t));
 565
 566 # ifdef __USE_GNU
 567 typedef __compar_fn_t comparison_fn_t;
 568 # endif
 569 #endif
 570
 571 /* Do a binary search for KEY in BASE, which consists of NMEMB elements
 572    of SIZE bytes each, using COMPAR to perform the comparisons.  */
 573 extern __ptr_t bsearch __PMT ((__const __ptr_t __key, __const __ptr_t __base,
 574                                size_t __nmemb, size_t __size,
 575                                __compar_fn_t __compar));
 576
 577 /* Sort NMEMB elements of BASE, of SIZE bytes each,
 578    using COMPAR to perform the comparisons.  */
 579 extern void qsort __PMT ((__ptr_t __base, size_t __nmemb, size_t __size,
 580                           __compar_fn_t __compar));
 581
 582
 583 /* Return the absolute value of X.  */
 584 extern int abs __P ((int __x)) __attribute__ ((__const__));
 585 extern long int labs __P ((long int __x)) __attribute__ ((__const__));
 586 #ifdef __USE_ISOC9X
 587 extern long long int llabs __P ((long long int __x))
 588      __attribute__ ((__const__));
 589 #endif
 590
 591
 592 /* Return the `div_t', `ldiv_t' or `lldiv_t' representation
 593    of the value of NUMER over DENOM. */
 594 /* GCC may have built-ins for these someday.  */
 595 extern div_t div __P ((int __numer, int __denom)) __attribute__ ((__const__));
 596 extern ldiv_t ldiv __P ((long int __numer, long int __denom))
 597      __attribute__ ((__const__));
 598 #ifdef __USE_ISOC9X
 599 extern lldiv_t lldiv __P ((long long int __numer, long long int __denom))
 600      __attribute__ ((__const__));
 601 #endif
 602
 603
 604 #if defined __USE_SVID || defined __USE_XOPEN_EXTENDED
 605 /* Convert floating point numbers to strings.  The returned values are
 606    valid only until another call to the same function.  */
 607
 608 /* Convert VALUE to a string with NDIGIT digits and return a pointer to
 609    this.  Set *DECPT with the position of the decimal character and *SIGN
 610    with the sign of the number.  */
 611 extern char *ecvt __P ((double __value, int __ndigit, int *__decpt,
 612                         int *__sign));
 613
 614 /* Convert VALUE to a string rounded to NDIGIT decimal digits.  Set *DECPT
 615    with the position of the decimal character and *SIGN with the sign of
 616    the number.  */
 617 extern char *fcvt __P ((double __value, int __ndigit, int *__decpt,
 618                         int *__sign));
 619
 620 /* If possible convert VALUE to a string with NDIGIT significant digits.
 621    Otherwise use exponential representation.  The resulting string will
 622    be written to BUF.  */
 623 extern char *gcvt __P ((double __value, int __ndigit, char *__buf));
 624
 625 /* Long double versions of above functions.  */
 626 extern char *qecvt __P ((__long_double_t __value, int __ndigit, int *__decpt,
 627                          int *__sign));
 628 extern char *qfcvt __P ((__long_double_t __value, int __ndigit, int *__decpt,
 629                          int *__sign));
 630 extern char *qgcvt __P ((__long_double_t __value, int __ndigit, char *__buf));
 631
 632
 633 # ifdef __USE_MISC
 634 /* Reentrant version of the functions above which provide their own
 635    buffers.  */
 636 extern int ecvt_r __P ((double __value, int __ndigit, int *__decpt,
 637                         int *__sign, char *__buf, size_t __len));
 638 extern int fcvt_r __P ((double __value, int __ndigit, int *__decpt,
 639                         int *__sign, char *__buf, size_t __len));
 640
 641 extern int qecvt_r __P ((__long_double_t __value, int __ndigit, int *__decpt,
 642                          int *__sign, char *__buf, size_t __len));
 643 extern int qfcvt_r __P ((__long_double_t __value, int __ndigit, int *__decpt,
 644                          int *__sign, char *__buf, size_t __len));
 645 # endif /* misc */
 646 #endif  /* use MISC || use X/Open Unix */
 647
 648
 649 /* Return the length of the multibyte character
 650    in S, which is no longer than N.  */
 651 extern int mblen __P ((__const char *__s, size_t __n));
 652 /* Return the length of the given multibyte character,
 653    putting its `wchar_t' representation in *PWC.  */
 654 extern int mbtowc __P ((wchar_t *__restrict __pwc,
 655                         __const char *__restrict __s, size_t __n));
 656 /* Put the multibyte character represented
 657    by WCHAR in S, returning its length.  */
 658 extern int wctomb __P ((char *__s, wchar_t __wchar));
 659
 660
 661 /* Convert a multibyte string to a wide char string.  */
 662 extern size_t mbstowcs __P ((wchar_t *__restrict  __pwcs,
 663                              __const char *__restrict __s, size_t __n));
 664 /* Convert a wide char string to multibyte string.  */
 665 extern size_t wcstombs __P ((char *__restrict __s,
 666                              __const wchar_t *__restrict __pwcs, size_t __n));
 667
 668
 669 #ifdef __USE_SVID
 670 /* Determine whether the string value of RESPONSE matches the affirmation
 671    or negative response expression as specified by the LC_MESSAGES category
 672    in the program's current locale.  Returns 1 if affirmative, 0 if
 673    negative, and -1 if not matching.  */
 674 extern int rpmatch __P ((__const char *__response));
 675 #endif
 676
 677
 678 #ifdef __USE_XOPEN_EXTENDED
 679 /* Parse comma separated suboption from *OPTIONP and match against
 680    strings in TOKENS.  If found return index and set *VALUEP to
 681    optional value introduced by an equal sign.  If the suboption is
 682    not part of TOKENS return in *VALUEP beginning of unknown
 683    suboption.  On exit *OPTIONP is set to the beginning of the next
 684    token or at the terminating NUL character.  */
 685 extern int getsubopt __P ((char **__optionp, __const char *__const *__tokens,
 686                            char **__valuep));
 687 #endif
 688
 689
 690 #ifdef __USE_XOPEN
 691
 692 /* Setup DES tables according KEY.  */
 693 extern void setkey __P ((__const char *__key));
 694
 695 /* X/Open pseudo terminal handling.  */
 696
 697 /* The next four functions all take a master pseudo-tty fd and
 698    perform an operation on the associated slave:  */
 699
 700 /* Chown the slave to the calling user.  */
 701 extern int grantpt __P ((int __fd));
 702
 703 /* Release an internal lock so the slave can be opened.
 704    Call after grantpt().  */
 705 extern int unlockpt __P ((int __fd));
 706
 707 /* Return the pathname of the pseudo terminal slave assoicated with
 708    the master FD is open on, or NULL on errors.
 709    The returned storage is good until the next call to this function.  */
 710 extern char *ptsname __P ((int __fd));
 711 #endif
 712
 713 #ifdef __USE_GNU
 714 /* Store at most BUFLEN characters of the pathname of the slave pseudo
 715    terminal associated with the master FD is open on in BUF.
 716    Return 0 on success, otherwise an error number.  */
 717 extern int ptsname_r __P ((int __fd, char *__buf, size_t __buflen));
 718
 719 /* Open a master pseudo terminal and return its file descriptor.  */
 720 extern int getpt __P ((void));
 721 #endif
 722
 723 __END_DECLS
 724
 725 #endif /* stdlib.h  */