newlib/libc/search/qsort_r.c

   1 /*
   2 FUNCTION
   3 <<qsort_r>>---sort an array
   4
   5 INDEX
   6         qsort_r
   7
   8 SYNOPSIS
   9         #define _BSD_SOURCE
  10         #include <stdlib.h>
  11         void qsort_r(void *<[base]>, size_t <[nmemb]>, size_t <[size]>,
  12                      void *<[thunk]>,
  13                      int (*<[compar]>)(void*, const void *, const void *));
  14
  15         #define _GNU_SOURCE
  16         #include <stdlib.h>
  17         void qsort_r(void *<[base]>, size_t <[nmemb]>, size_t <[size]>,
  18                      int (*<[compar]>)(const void *, const void *, void *),
  19                      void *<[thunk]>);
  20
  21 DESCRIPTION
  22 <<qsort_r>> sorts an array (beginning at <[base]>) of <[nmemb]> objects.
  23 <[size]> describes the size of each element of the array.
  24
  25 You must supply a pointer to a comparison function, using the argument
  26 shown as <[compar]>.  (This permits sorting objects of unknown
  27 properties.)  There are two forms of this function, in each the
  28 comparison function is defined to accept three arguments, but in a
  29 different order.  Two are pointers to an element of the array starting at
  30 <[base]>, and another being an arbitrary pointer <[thunk]>.  The
  31 result of <<(*<[compar]>)>> must be negative if the first argument is
  32 less than the second, zero if the two arguments match, and positive if
  33 the first argument is greater than the second (where ``less than'' and
  34 ``greater than'' refer to whatever arbitrary ordering is appropriate).
  35
  36 The array is sorted in place; that is, when <<qsort_r>> returns, the
  37 array elements beginning at <[base]> have been reordered.
  38
  39 RETURNS
  40 <<qsort_r>> does not return a result.
  41
  42 PORTABILITY
  43 <<qsort_r>>, in various forms, appears in both BSD and glibc.
  44 */
  45
  46 #define _GNU_SOURCE
  47 #define I_AM_GNU_QSORT_R
  48 #include "qsort.c"