lib/astrxfrm.h

   1 /* Locale dependent string transformation for comparison.
   2    Copyright (C) 2010-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify it
   5    under the terms of the GNU Lesser General Public License as published
   6    by the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program 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 License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #ifndef ASTRXFRM_H
  18 #define ASTRXFRM_H
  19
  20 #include <stddef.h>
  21
  22 #ifdef __cplusplus
  23 extern "C" {
  24 #endif
  25
  26
  27 /* Variant of strxfrm() with a calling convention that reduces the number
  28    of strxfrm calls.  */
  29
  30 /* Transform the string starting at S to a string, in such a way that
  31    comparing S1 and S2 with strcoll() is equivalent to comparing astrxfrm(S1)
  32    and astrxfrm(S2) with strcmp().
  33    The result of this function depends on the LC_COLLATE category of the
  34    current locale.
  35    If successful: If resultbuf is not NULL and the result fits into *lengthp
  36    bytes, it is put in resultbuf, and resultbuf is returned.  Otherwise, a
  37    freshly allocated string is returned.  In both cases, *lengthp is set to the
  38    length of the returned string.
  39    Upon failure, return NULL, with errno set.  */
  40 extern char * astrxfrm (const char *s,
  41                         char *restrict resultbuf, size_t *lengthp);
  42
  43
  44 #ifdef __cplusplus
  45 }
  46 #endif
  47
  48 #endif /* ASTRXFRM_H */