Glibc

Moving toward a standarized qsort_r(3)

History of qsort_r(3)

First introduced in Research Unix V3 and eventually standardized as part of C Standard Library as of ANSI/ISO C89, qsort(3) provided an abstract interface where programmers can perform sort operation over an array of objects, by supplying a pointer to that array, the total number of the member objects, the size of individual member object, as well as a compare function. The compare function is expected to take two parameters, both pointers to a member object, and it shall return a negative number, 0, or a positive number, if the first object is considered smaller, equal, or greater respectively.