qsort

Sorts an array of objects in place. It implements the quick-sort algorithm.

Format

#include  <stdlib.h>

void qsort  (void *base, size_t nmemb, size_t
            size, int (*compar) (const void *,
            const void *));

Function Variants This function also has variants named _qsort32 and _qsort64 for use with 32-bit and 64-bit pointer sizes, respectively. See Section 1.8 for more information on using pointer-size-specific functions.

Arguments

base: A pointer to the first member of the array. The pointer should be of type pointer-to-element and cast to type pointer-to-character.
nmemb: The number of objects in the array.
size: The size of an object, in bytes.
compar: A pointer to the comparison function.

Description

Two arguments are passed to the comparison function pointed to by compar. The two arguments point to the objects being compared. Depending on whether the first argument is less than, equal to, or greater than the second argument, the comparison function returns an integer less then, equal to, or greater than 0.

The comparison function compar need not compare every byte, so arbitrary data might be contained in the objects in addition to the values being compared.

The order in the output of two objects that compare as equal is unpredictable.

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