NAME

qsort() − quicker sort

SYNOPSIS

#include <stdlib.h>

void qsort(

void *base,
size_t nel,
size_t size,
int (*compar)(const void *, const void *)

);

DESCRIPTION

qsort() is an implementation of the quicker-sort algorithm.  It sorts a table of data in place. 

base Pointer to the element at the base of the table. 

nel Number of elements in the table. 

size Size of each element in the table. 

compar Name of the comparison function, which is called with two arguments that point to the elements being compared.  The function passed as compar must return an integer less than, equal to, or greater than zero, according to whether its first argument is to be considered less than, equal to, or greater than the second.  strcmp() uses this same return convention (see strcmp(3C)).

NOTES

The pointer to the base of the table should be of type pointer-to-element, and cast to type pointer-to-void. 

The comparison function need not compare every byte; thus, arbitrary data can be contained in the elements in addition to the values being compared. 

The order in the output of two items which compare as equal is unpredictable. 

SEE ALSO

sort(1), bsearch(3C), lsearch(3C), string(3C). 

WARNINGS

If size is zero, a divide-by-zero error might be generated. 

STANDARDS CONFORMANCE

qsort(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C

Hewlett-Packard Company  —  HP-UX Release 9.10: April 1995