(en.cppreference.com) qsort, qsort_s - cppreference.com

ROAM_REFS: https://en.cppreference.com/w/c/algorithm/qsort

• qsort, qsort_s

Defined in header

<stdlib.h>

void qsort( void* ptr, [[http://en.cppreference.com/w/c/types/size_t][size_t]] count, [[http://en.cppreference.com/w/c/types/size_t][size_t]] size,
            int (*comp)(const void*, const void*) );
errno_t qsort_s( void* ptr, rsize_t count, rsize_t size,
                 int (*comp)(const void*, const void*, void*),
                 void* context );

1. Sorts the given array pointed to by

   ptr

   in ascending order. The array contains

   count

   elements of

   size

   bytes. Function pointed to by

   comp

   is used for object comparison.

2. Same as (1), except that the additional context parameter context is passed to comp and that the following errors are detected at runtime and call the currently installed constraint handler function:

   • count

     or

     size

     is greater than RSIZE_MAX

   • ptr

     or

     comp

     is a null pointer (unless

     count

     is zero)

   As with all bounds-checked functions,

   qsort_s

   is only guaranteed to be available if

   __STDC_LIB_EXT1__

   is defined by the implementation and if the user defines

   __STDC_WANT_LIB_EXT1__

   to the integer constant 1 before including

   <stdlib.h>

   .

If comp indicates two elements as equivalent, their order in the resulting sorted array is unspecified.

* Parameters

ptr - pointer to the array to sort count - number of elements in the array size - size of each element in the array in bytes comp - comparison function which returns ​a negative integer value if the first argument is less than the second, a positive integer value if the first argument is greater than the second and zero if the arguments are equivalent. The signature of the comparison function should be equivalent to the following:

The function must not modify the objects passed to it and must return consistent results when called for the same objects, regardless of their positions in the array. context - additional information (e.g., collating sequence), passed to

comp

as the third argument

* Return value

1. (none)
2. zero on success, non-zero if a runtime constraints violation was detected