usr/src/lib/libc/stdlib/qsort.3

.\" Copyright (c) 1990 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)qsort.3     6.3 (Berkeley) %G%
.\"
.TH QSORT 3  ""
.UC 4
.SH NAME
qsort \- quicker sort
.SH SYNOPSIS
.nf
.ft B
#include <stdlib.h>

void
qsort(void *base, size_t nmemb, size_t size,
int (*compar)(const void *, const void *));
.ft R
.fi
.SH DESCRIPTION
.I Qsort
is an implementation of C.A.R. Hoare's ``quicksort'' algorithm.
.PP
The
.I qsort
function sorts an array of
.I nmemb
objects, the initial member of which is pointed to by
.IR base .
The size of each object is specified by
.IR size .
.PP
The contents of the array are sorted in ascending order according to
a comparison function pointed to by
.IR compar ,
which is called with two arguments that point to the objects being
compared.
.PP
The comparison function must return an integer less than, equal to, or
greater than zero if the first argument is considered to be respectively
less than, equal to, or greater than the second.
.PP
If two members compare as equal, their order in the sorted array is
undefined.
.SH "SEE ALSO"
sort(1)
.SH STANDARDS
.B Qsort
conforms to ANSI X3.159-1989 (``ANSI C'').
.SH BUGS
The comparison routine may not itself call
.IR qsort (3).