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qsort(3C)		 Standard C Library Functions		     qsort(3C)

NAME
       qsort - quick sort

SYNOPSIS
       #include	<stdlib.h>

       void  qsort(void	 *base,	 size_t	nel, size_t width, int (*compar)(const
       void *, const void *));

DESCRIPTION
       The qsort() function is an implementation of the	quick-sort  algorithm.
       It sorts	a table	of data	in place. The contents of the table are	sorted
       in ascending order according to the  user-supplied comparison function.

       The  base argument points to the	element	at the base of the table.  The
       nel argument is the number of elements in the table.  The  width	 argu-
       ment  specifies the size	of each	element	in bytes.  The compar argument
       is the name of the comparison function, which is	called with two	 argu-
       ments that point	to the elements	being compared.

       The  function  must  return  an integer less than, equal	to, or greater
       than zero to indicate if	the first argument is to  be  considered  less
       than, equal to, or greater than the second argument.

       The  contents  of  the table are	sorted in ascending order according to
       the user	supplied comparison function.

USAGE
       The qsort() function  safely  allows  concurrent	 access	 by   multiple
       threads to disjoint data, such as overlapping subtrees or tables.

EXAMPLES
       Example 1: Program sorts.

       The following program sorts a simple array:

       #include	<stdlib.h>
       #include	<stdio.h>

       static int
       intcompare(const	void *p1, const	void *p2)
       {
	   int i = *((int *)p1);
	   int j = *((int *)p2);

	   if (i > j)
	       return (1);
	   if (i < j)
	       return (-1);
	   return (0);
       }

       int
       main()
       {
	   int i;
	   int a[10] = { 9, 8, 7, 6, 5,	4, 3, 2, 1, 0 };
	   size_t nelems = sizeof (a) /	sizeof (int);

	   qsort((void *)a, nelems, sizeof (int), intcompare);

	   for (i = 0; i < nelems; i++)	{
	       (void) printf("%d ", a[i]);
	   }

	   (void) printf("\n");
	   return (0);
       }

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       sort(1),	 bsearch(3C),  lsearch(3C),  string(3C),  attributes(5), stan-
       dards(5)

NOTES
       The comparison function need not	compare	every byte, so arbitrary  data
       may  be	contained in the elements in addition to the values being com-
       pared.

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

SunOS 5.10			  6 Dec	2004			     qsort(3C)

NAME | SYNOPSIS | DESCRIPTION | USAGE | EXAMPLES | ATTRIBUTES | SEE ALSO | NOTES

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