Function qsort 

pub fn qsort<T, E, F>(data: &mut [T], cmp: &mut F) -> Result<(), E>
where
    F: FnMut(&T, &T) -> Result<Ordering, E>,

pg_qsort: a quicksort with the median of three or of nine, a partition in three parts and an insertion sort for fewer than 7 items. It is not stable. The sort stops at the first error of cmp.

Errors

The first error of cmp.