In the wiki an int compare(int * , int * ) function [1] is used, which is odd if the elements are not pointers (when P is defined). Shouldn't it be changed to int compare(int, int) when P is defined? I wonder if it impacts at all the benchmarks.
The compare nomenclature is a one size fits all, given larger structs require a pointer to prevent large amount of copies. Think of qsorts compare, which uses two void* arguments.
[1] https://github.com/glouw/ctl/blob/49b90312f9473057fd2ed77941...