Synopsis

void qsort(void *buf,
           size_t num,
           size_t size,
           int (*compare)(const void *, const void *));

qsort sorts the array *base using the compare algorithm. The array should have num elements of size bytes. The compare function should return a negative value if the first parameter is less than second parameter, zero if the parameters are equal and a positive value if the first parameter is greater than the second parameter.