stdlib/stdlib.h

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96 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 S Standard: 4.10 GENERAL UTILITIES  <stdlib.h>
  21  */
  22
  23 #ifndef _STDLIB_H
  24
  25 #define _STDLIB_H       1
  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_GNU
  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 /* Convert a string to a floating-point number.  */
  83 extern double strtod __P ((__const char *__nptr, char **__endptr));
  84
  85 #ifdef  __USE_GNU
  86 /* Likewise for `float' and `long double' sizes of floating-point numbers.  */
  87 extern float strtof __P ((__const char *__nptr, char **__endptr));
  88 extern __long_double_t strtold __P ((__const char *__nptr, char **__endptr));
  89 #endif
  90
  91 /* Convert a string to a long integer.  */
  92 extern long int strtol __P ((__const char *__nptr, char **__endptr,
  93                              int __base));
  94 /* Convert a string to an unsigned long integer.  */
  95 extern unsigned long int strtoul __P ((__const char *__nptr,
  96                                        char **__endptr, int __base));
  97
  98 #if defined (__GNUC__) && defined (__USE_BSD)
  99 /* Convert a string to a quadword integer.  */
 100 extern long long int strtoq __P ((__const char *__nptr, char **__endptr,
 101                                   int __base));
 102 /* Convert a string to an unsigned quadword integer.  */
 103 extern unsigned long long int strtouq __P ((__const char *__nptr,
 104                                             char **__endptr, int __base));
 105 #endif /* GCC and use BSD.  */
 106
 107 #if defined (__GNUC__) && defined (__USE_MISC)
 108 /* Convert a string to a quadword integer.  */
 109 extern long long int strtoll __P ((__const char *__nptr, char **__endptr,
 110                                    int __base));
 111 /* Convert a string to an unsigned quadword integer.  */
 112 extern unsigned long long int strtoull __P ((__const char *__nptr,
 113                                              char **__endptr, int __base));
 114 #endif /* GCC and use MISC.  */
 115
 116
 117
 118 /* The internal entry points for `strtoX' take an extra flag argument
 119    saying whether or not to parse locale-dependent number grouping.  */
 120
 121 extern double __strtod_internal __P ((__const char *__nptr,
 122                                       char **__endptr, int __group));
 123 extern float __strtof_internal __P ((__const char *__nptr, char **__endptr,
 124                                      int __group));
 125 extern __long_double_t __strtold_internal __P ((__const char *__nptr,
 126                                                 char **__endptr, int __group));
 127 extern long int __strtol_internal __P ((__const char *__nptr, char **__endptr,
 128                                         int __base, int __group));
 129 extern unsigned long int __strtoul_internal __P ((__const char *__nptr,
 130                                                   char **__endptr, int __base,
 131                                                   int __group));
 132 #ifdef __GNUC__
 133 extern long long int __strtoq_internal __P ((__const char *__nptr,
 134                                              char **__endptr, int __base,
 135                                              int __group));
 136 extern unsigned long long int __strtouq_internal __P ((__const char *__nptr,
 137                                                        char **__endptr,
 138                                                        int __base,
 139                                                        int __group));
 140 #endif /* GCC */
 141
 142 #if defined (__OPTIMIZE__) && __GNUC__ >= 2
 143 /* Define inline functions which call the internal entry points.  */
 144
 145 extern __inline double strtod (__const char *__nptr, char **__endptr)
 146 { return __strtod_internal (__nptr, __endptr, 0); }
 147 extern __inline long int strtol (__const char *__nptr,
 148                                  char **__endptr, int __base)
 149 { return __strtol_internal (__nptr, __endptr, __base, 0); }
 150 extern __inline unsigned long int strtoul (__const char *__nptr,
 151                                            char **__endptr, int __base)
 152 { return __strtoul_internal (__nptr, __endptr, __base, 0); }
 153
 154 #ifdef __USE_GNU
 155 extern __inline float strtof (__const char *__nptr, char **__endptr)
 156 { return __strtof_internal (__nptr, __endptr, 0); }
 157 extern __inline __long_double_t strtold (__const char *__nptr, char **__endptr)
 158 { return __strtold_internal (__nptr, __endptr, 0); }
 159 #endif
 160
 161 #ifdef __USE_BSD
 162 extern __inline long long int strtoq (__const char *__nptr, char **__endptr,
 163                                       int __base)
 164 { return __strtoq_internal (__nptr, __endptr, __base, 0); }
 165 extern __inline unsigned long long int strtouq (__const char *__nptr,
 166                                                 char **__endptr, int __base)
 167 { return __strtouq_internal (__nptr, __endptr, __base, 0); }
 168 #endif
 169
 170 #ifdef __USE_MISC
 171 extern __inline long long int strtoll (__const char *__nptr, char **__endptr,
 172                                        int __base)
 173 { return __strtoq_internal (__nptr, __endptr, __base, 0); }
 174 extern __inline unsigned long long int strtoull (__const char *__nptr,
 175                                                  char **__endptr, int __base)
 176 { return __strtouq_internal (__nptr, __endptr, __base, 0); }
 177 #endif
 178
 179 extern __inline double atof (__const char *__nptr)
 180 { return strtod (__nptr, (char **) NULL); }
 181 extern __inline int atoi (__const char *__nptr)
 182 { return (int) strtol (__nptr, (char **) NULL, 10); }
 183 extern __inline long int atol (__const char *__nptr)
 184 { return strtol (__nptr, (char **) NULL, 10); }
 185 #endif /* Optimizing GCC >=2.  */
 186
 187
 188 #if defined(__USE_SVID) || defined(__USE_XOPEN_EXTENDED)
 189 /* Convert N to base 64 using the digits "./0-9A-Za-z", least-significant
 190    digit first.  Returns a pointer to static storage overwritten by the
 191    next call.  */
 192 extern char *l64a __P ((long int __n));
 193
 194 /* Read a number from a string S in base 64 as above.  */
 195 extern long int a64l __P ((__const char *__s));
 196
 197
 198 #include <sys/types.h>  /* we need int32_t... */
 199
 200 /* These are the functions that actually do things.  The `random', `srandom',
 201    `initstate' and `setstate' functions are those from BSD Unices.
 202    The `rand' and `srand' functions are required by the ANSI standard.
 203    We provide both interfaces to the same random number generator.  */
 204 /* Return a random long integer between 0 and RAND_MAX inclusive.  */
 205 extern int32_t __random __P ((void));
 206 extern int32_t random __P ((void));
 207
 208 /* Seed the random number generator with the given number.  */
 209 extern void __srandom __P ((unsigned int __seed));
 210 extern void srandom __P ((unsigned int __seed));
 211
 212 /* Initialize the random number generator to use state buffer STATEBUF,
 213    of length STATELEN, and seed it with SEED.  Optimal lengths are 8, 16,
 214    32, 64, 128 and 256, the bigger the better; values less than 8 will
 215    cause an error and values greater than 256 will be rounded down.  */
 216 extern __ptr_t __initstate __P ((unsigned int __seed, __ptr_t __statebuf,
 217                                  size_t __statelen));
 218 extern __ptr_t initstate __P ((unsigned int __seed, __ptr_t __statebuf,
 219                                size_t __statelen));
 220
 221 /* Switch the random number generator to state buffer STATEBUF,
 222    which should have been previously initialized by `initstate'.  */
 223 extern __ptr_t __setstate __P ((__ptr_t __statebuf));
 224 extern __ptr_t setstate __P ((__ptr_t __statebuf));
 225
 226
 227 #ifdef __USE_REENTRANT
 228 /* Reentrant versions of the `random' family of functions.
 229    These functions all use the following data structure to contain
 230    state, rather than global state variables.  */
 231
 232 struct random_data
 233   {
 234     int32_t *fptr;              /* Front pointer.  */
 235     int32_t *rptr;              /* Rear pointer.  */
 236     int32_t *state;             /* Array of state values.  */
 237     int rand_type;              /* Type of random number generator.  */
 238     int rand_deg;               /* Degree of random number generator.  */
 239     int rand_sep;               /* Distance between front and rear.  */
 240     int32_t *end_ptr;           /* Pointer behind state table.  */
 241   };
 242
 243 extern int __random_r __P ((struct random_data *__buf, int32_t *__result));
 244 extern int random_r __P ((struct random_data *__buf, int32_t *__result));
 245
 246 extern int __srandom_r __P ((unsigned int __seed, struct random_data *__buf));
 247 extern int srandom_r __P ((unsigned int __seed, struct random_data *__buf));
 248
 249 extern int __initstate_r __P ((unsigned int __seed, __ptr_t __statebuf,
 250                                size_t __statelen, struct random_data *__buf));
 251 extern int initstate_r __P ((unsigned int __seed, __ptr_t __statebuf,
 252                              size_t __statelen, struct random_data *__buf));
 253
 254 extern int __setstate_r __P ((__ptr_t __statebuf, struct random_data *__buf));
 255 extern int setstate_r __P ((__ptr_t __statebuf, struct random_data *__buf));
 256 #endif  /* Use reentrant.  */
 257 #endif  /* Use BSD.  */
 258
 259
 260 /* Return a random integer between 0 and RAND_MAX inclusive.  */
 261 extern int rand __P ((void));
 262 /* Seed the random number generator with the given number.  */
 263 extern void srand __P ((unsigned int __seed));
 264
 265 #ifdef __USE_REENTRANT
 266 /* Reentrant interface according to POSIX.1.  */
 267 extern int __rand_r __P ((unsigned int *__seed));
 268 extern int rand_r __P ((unsigned int *__seed));
 269 #endif
 270
 271
 272 #if defined(__USE_SVID) || defined(__USE_XOPEN)
 273 /* System V style 48-bit random number generator functions.  */
 274
 275 /* Return non-negative, double-precision floating-point value in [0.0,1.0).  */
 276 extern double drand48 __P ((void));
 277 extern double erand48 __P ((unsigned short int __xsubi[3]));
 278
 279 /* Return non-negative, long integer in [0,2^31).  */
 280 extern long lrand48 __P ((void));
 281 extern long nrand48 __P ((unsigned short int __xsubi[3]));
 282
 283 /* Return signed, long integers in [-2^31,2^31).  */
 284 extern long mrand48 __P ((void));
 285 extern long jrand48 __P ((unsigned short int __xsubi[3]));
 286
 287 /* Seed random number generator.  */
 288 extern void srand48 __P ((long __seedval));
 289 extern unsigned short int *seed48 __P ((unsigned short int __seed16v[3]));
 290 extern void lcong48 __P ((unsigned short int __param[7]));
 291
 292 /* Data structure for communication with thread safe versions.  */
 293 struct drand48_data
 294   {
 295     unsigned short int X[3];    /* Current state.  */
 296     unsigned short int a[3];    /* Factor in congruential formula.  */
 297     unsigned short int c;       /* Additive const. in congruential formula.  */
 298     unsigned short int old_X[3]; /* Old state.  */
 299     int init;                   /* Flag for initializing.  */
 300   };
 301
 302 #ifdef __USE_REENTRANT
 303 /* Return non-negative, double-precision floating-point value in [0.0,1.0).  */
 304 extern int drand48_r __P ((struct drand48_data *__buffer, double *__result));
 305 extern int erand48_r __P ((unsigned short int __xsubi[3],
 306                            struct drand48_data *__buffer, double *__result));
 307
 308 /* Return non-negative, long integer in [0,2^31).  */
 309 extern int lrand48_r __P ((struct drand48_data *__buffer, long *__result));
 310 extern int nrand48_r __P ((unsigned short int __xsubi[3],
 311                            struct drand48_data *__buffer, long *__result));
 312
 313 /* Return signed, long integers in [-2^31,2^31).  */
 314 extern int mrand48_r __P ((struct drand48_data *__buffer, long *__result));
 315 extern int jrand48_r __P ((unsigned short int __xsubi[3],
 316                            struct drand48_data *__buffer, long *__result));
 317
 318 /* Seed random number generator.  */
 319 extern int srand48_r __P ((long __seedval, struct drand48_data *__buffer));
 320 extern int seed48_r __P ((unsigned short int __seed16v[3],
 321                           struct drand48_data *__buffer));
 322 extern int lcong48_r __P ((unsigned short int __param[7],
 323                            struct drand48_data *__buffer));
 324 #endif  /* Use reentrant.  */
 325
 326 /* Internal function to compute next state of the generator.  */
 327 extern int __drand48_iterate __P ((unsigned short int __xsubi[3],
 328                                    struct drand48_data *__buffer));
 329 #endif  /* Use SVID or X/Open.  */
 330
 331
 332 /* Allocate SIZE bytes of memory.  */
 333 extern __ptr_t malloc __P ((size_t __size));
 334 /* Re-allocate the previously allocated block
 335    in __ptr_t, making the new block SIZE bytes long.  */
 336 extern __ptr_t realloc __P ((__ptr_t __ptr, size_t __size));
 337 /* Allocate NMEMB elements of SIZE bytes each, all initialized to 0.  */
 338 extern __ptr_t calloc __P ((size_t __nmemb, size_t __size));
 339 /* Free a block allocated by `malloc', `realloc' or `calloc'.  */
 340 extern void free __P ((__ptr_t __ptr));
 341
 342 #ifdef  __USE_MISC
 343 /* Free a block.  An alias for `free'.  (Sun Unices).  */
 344 extern void cfree __P ((__ptr_t __ptr));
 345 #endif /* Use misc.  */
 346
 347 #if defined(__USE_GNU) || defined(__USE_BSD) || defined(__USE_MISC)
 348 #include <alloca.h>
 349 #endif /* Use GNU, BSD, or misc.  */
 350
 351 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 352 /* Allocate SIZE bytes on a page boundary.  The storage cannot be freed.  */
 353 extern __ptr_t valloc __P ((size_t __size));
 354 #endif
 355
 356
 357 /* Abort execution and generate a core-dump.  */
 358 extern void abort __P ((void)) __attribute__ ((__noreturn__));
 359
 360
 361 /* Register a function to be called when `exit' is called.  */
 362 extern int atexit __P ((void (*__func) (void)));
 363
 364 #ifdef  __USE_MISC
 365 /* Register a function to be called with the status
 366    given to `exit' and the given argument.  */
 367 extern int __on_exit __P ((void (*__func) (int __status, __ptr_t __arg),
 368                            __ptr_t __arg));
 369 extern int on_exit __P ((void (*__func) (int __status, __ptr_t __arg),
 370                          __ptr_t __arg));
 371 #endif
 372
 373 /* Call all functions registered with `atexit' and `on_exit',
 374    in the reverse of the order in which they were registered
 375    perform stdio cleanup, and terminate program execution with STATUS.  */
 376 extern void exit __P ((int __status)) __attribute__ ((__noreturn__));
 377
 378
 379 /* Return the value of envariable NAME, or NULL if it doesn't exist.  */
 380 extern char *getenv __P ((__const char *__name));
 381
 382 /* This function is similar to the above but returns NULL if the
 383    programs is running with SUID or SGID enabled.  */
 384 extern char *__secure_getenv __P ((__const char *__name));
 385
 386 #if defined(__USE_SVID) || defined(__USE_XOPEN)
 387 /* The SVID says this is in <stdio.h>, but this seems a better place.   */
 388 /* Put STRING, which is of the form "NAME=VALUE", in the environment.
 389    If there is no `=', remove NAME from the environment.  */
 390 extern int putenv __P ((__const char *__string));
 391 #endif
 392
 393 #ifdef  __USE_BSD
 394 /* Set NAME to VALUE in the environment.
 395    If REPLACE is nonzero, overwrite an existing value.  */
 396 extern int setenv __P ((__const char *__name, __const char *__value,
 397                         int __replace));
 398
 399 /* Remove the variable NAME from the environment.  */
 400 extern void unsetenv __P ((__const char *__name));
 401 #endif
 402
 403 #ifdef  __USE_MISC
 404 /* The `clearenv' was planned to be added to POSIX.1 but probably
 405    never made it.  Nevertheless the POSIX.9 standard (POSIX bindings
 406    for Fortran 77) requires this function.  */
 407 extern int clearenv __P ((void));
 408 #endif
 409
 410
 411 #if defined(__USE_MISC) || defined(__USE_XOPEN_EXTENDED)
 412 /* Generate a unique temporary file name from TEMPLATE.
 413    The last six characters of TEMPLATE must be "XXXXXX";
 414    they are replaced with a string that makes the file name unique.
 415    Returns TEMPLATE, or a null pointer if it cannot get a unique file name.  */
 416 extern char *mktemp __P ((char *__template));
 417
 418 /* Generate a unique temporary file name from TEMPLATE.
 419    The last six characters of TEMPLATE must be "XXXXXX";
 420    they are replaced with a string that makes the filename unique.
 421    Returns a file descriptor open on the file for reading and writing,
 422    or -1 if it cannot create a uniquely-named file.  */
 423 extern int mkstemp __P ((char *__template));
 424 #endif
 425
 426
 427 /* Execute the given line as a shell command.  */
 428 extern int system __P ((__const char *__command));
 429
 430
 431 #ifdef  __USE_GNU
 432 /* Return a malloc'd string containing the canonical absolute name of the
 433    named file.  The last file name component need not exist, and may be a
 434    symlink to a nonexistent file.  */
 435 extern char *canonicalize_file_name __P ((__const char *__name));
 436 #endif
 437
 438 #if defined(__USE_BSD) || defined(__USE_XOPEN_EXTENDED)
 439 /* Return the canonical absolute name of file NAME.  The last file name
 440    component need not exist, and may be a symlink to a nonexistent file.
 441    If RESOLVED is null, the result is malloc'd; otherwise, if the canonical
 442    name is PATH_MAX chars or more, returns null with `errno' set to
 443    ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars, returns the
 444    name in RESOLVED.  */
 445 extern char *realpath __P ((__const char *__name, char *__resolved));
 446 #endif
 447
 448
 449 /* Shorthand for type of comparison functions.  */
 450 #ifndef __COMPAR_FN_T
 451 #define __COMPAR_FN_T
 452 typedef int (*__compar_fn_t) __P ((__const __ptr_t, __const __ptr_t));
 453 #endif
 454
 455 #ifdef  __USE_GNU
 456 typedef __compar_fn_t comparison_fn_t;
 457 #endif
 458
 459 /* Do a binary search for KEY in BASE, which consists of NMEMB elements
 460    of SIZE bytes each, using COMPAR to perform the comparisons.  */
 461 extern __ptr_t bsearch __P ((__const __ptr_t __key, __const __ptr_t __base,
 462                              size_t __nmemb, size_t __size,
 463                              __compar_fn_t __compar));
 464
 465 /* Sort NMEMB elements of BASE, of SIZE bytes each,
 466    using COMPAR to perform the comparisons.  */
 467 extern void qsort __P ((__ptr_t __base, size_t __nmemb, size_t __size,
 468                         __compar_fn_t __compar));
 469
 470
 471 /* Return the absolute value of X.  */
 472 extern int abs __P ((int __x)) __attribute__ ((__const__));
 473 extern long int labs __P ((long int __x)) __attribute__ ((__const__));
 474 #ifdef __USE_GNU
 475 extern long long int llabs __P ((long long int __x)) __attribute__ ((__const__));
 476 #endif
 477
 478
 479 /* Return the `div_t', `ldiv_t' or `lldiv_t' representation
 480    of the value of NUMER over DENOM. */
 481 /* GCC may have built-ins for these someday.  */
 482 extern div_t div __P ((int __numer, int __denom)) __attribute__ ((__const__));
 483 extern ldiv_t ldiv __P ((long int __numer, long int __denom)) __attribute__ ((__const__));
 484 #ifdef __USE_GNU
 485 extern lldiv_t lldiv __P ((long long int __numer, long long int __denom)) __attribute__ ((__const__));
 486 #endif
 487
 488
 489 #if defined(__USE_SVID) || defined(__USE_XOPEN_EXTENDED)
 490 /* Convert floating point numbers to strings.  The returned values are
 491    valid only until another call to the same function.  */
 492
 493 /* Convert VALUE to a string with NDIGIT digits and return a pointer to
 494    this.  Set *DECPT with the position of the decimal character and *SIGN
 495    with the sign of the number.  */
 496 extern char *ecvt __P ((double __value, int __ndigit, int *__decpt,
 497                         int *__sign));
 498
 499 /* Convert VALUE to a string rounded to NDIGIT decimal digits.  Set *DECPT
 500    with the position of the decimal character and *SIGN with the sign of
 501    the number.  */
 502 extern char *fcvt __P ((double __value, int __ndigit, int *__decpt,
 503                         int *__sign));
 504
 505 /* If possible convert VALUE to a string with NDIGIT significant digits.
 506    Otherwise use exponential representation.  The resulting string will
 507    be written to BUF.  */
 508 extern char *gcvt __P ((double __value, int __ndigit, char *__buf));
 509
 510 /* Long double versions of above functions.  */
 511 extern char *qecvt __P ((__long_double_t __value, int __ndigit, int *__decpt,
 512                          int *__sign));
 513 extern char *qfcvt __P ((__long_double_t __value, int __ndigit, int *__decpt,
 514                          int *__sign));
 515 extern char *qgcvt __P ((__long_double_t __value, int __ndigit, char *__buf));
 516
 517
 518 #ifdef __USE_REENTRANT
 519 /* Reentrant version of the functions above which provide their own
 520    buffers.  */
 521 extern int ecvt_r __P ((double __value, int __ndigit, int *__decpt,
 522                         int *__sign, char *__buf, size_t __len));
 523 extern int fcvt_r __P ((double __value, int __ndigit, int *__decpt,
 524                         int *__sign, char *__buf, size_t __len));
 525
 526 extern int qecvt_r __P ((__long_double_t __value, int __ndigit, int *__decpt,
 527                          int *__sign, char *__buf, size_t __len));
 528 extern int qfcvt_r __P ((__long_double_t __value, int __ndigit, int *__decpt,
 529                          int *__sign, char *__buf, size_t __len));
 530 #endif  /* reentrant */
 531 #endif  /* use MISC || use X/Open Unix */
 532
 533
 534 /* Return the length of the multibyte character
 535    in S, which is no longer than N.  */
 536 extern int mblen __P ((__const char *__s, size_t __n));
 537 /* Return the length of the given multibyte character,
 538    putting its `wchar_t' representation in *PWC.  */
 539 extern int mbtowc __P ((wchar_t *__pwc, __const char *__s, size_t __n));
 540 /* Put the multibyte character represented
 541    by WCHAR in S, returning its length.  */
 542 extern int wctomb __P ((char *__s, wchar_t __wchar));
 543
 544 #if defined (__OPTIMIZE__) && __GNUC__ >= 2
 545 extern __inline int mblen (__const char *__s, size_t __n)
 546 { return mbtowc ((wchar_t *) NULL, __s, __n); }
 547 #endif /* Optimizing GCC >=2.  */
 548
 549
 550 /* Convert a multibyte string to a wide char string.  */
 551 extern size_t mbstowcs __P ((wchar_t *__pwcs, __const char *__s, size_t __n));
 552 /* Convert a wide char string to multibyte string.  */
 553 extern size_t wcstombs __P ((char *__s, __const wchar_t *__pwcs, size_t __n));
 554
 555
 556 #ifdef __USE_SVID
 557 /* Determine whether the string value of RESPONSE matches the affirmation
 558    or negative response expression as specified by the LC_MESSAGES category
 559    in the program's current locale.  Returns 1 if affirmative, 0 if
 560    negative, and -1 if not matching.  */
 561 extern int rpmatch __P ((__const char *__response));
 562 #endif
 563
 564
 565 #ifdef __USE_XOPEN_EXTENDED
 566 /* Parse comma separated suboption from *OPTIONP and match against
 567    strings in TOKENS.  If found return index and set *VALUEP to
 568    optional value introduced by an equal sign.  If the suboption is
 569    not part of TOKENS return in *VALUEP beginning of unknown
 570    suboption.  On exit *OPTIONP is set to the beginning of the next
 571    otken or at the terminating NUL character.  */
 572 extern int getsubopt __P ((char **__optionp, __const char *__const *__tokens,
 573                            char **__valuep));
 574 #endif
 575
 576
 577 #ifdef __USE_XOPEN
 578
 579 /* Setup DES tables according KEY.  */
 580 extern void setkey __P ((__const char *__key));
 581 #endif
 582
 583
 584 __END_DECLS
 585
 586 #endif /* stdlib.h  */