qsort(3) -- Linux man page
NAMEqsort - sorts an array
#include <stdlib.h> void qsort(void *base, size_t nmemb, size_t size, int(*compar)(const void *, const void *));
DESCRIPTIONThe qsort() function sorts an array with nmemb elements of size size. The base argument points to the start of the array.
The contents of the array are sorted in ascending order according to a comparison function pointed to by compar, which is called with two arguments that point to the objects being compared.
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. If two members compare as equal, their order in the sorted array is undefined.
RETURN VALUEThe qsort() function returns no value.
CONFORMING TOSVID 3, POSIX, BSD 4.3, ISO 9899
NOTELibrary routines suitable for use as the compar argument include strcmp, alphasort, and versionsort.
EXAMPLEFor an example of use, see the example on the bsearch(3) page.
SEE ALSOsort(1), alphasort(3), strcmp(3), versionsort(3)