Is it possible to use function pointers with critcl?

Question

I'm starting to use critcl, and I encountered a situation where a library requires a pointer to a function.

This is a simpler situation:

I want to write a sorting function in C, using qsort somewhat like the example in https://www.geeksforgeeks.org/comparator-function-of-qsort-in-c/ I want to write the comparator in tcl, something like this:

proc comparator {p q} {
    if {($p % 2) && ($q % 2)} {
        return [expr {$p > $q} ]
    }
    if {!($p % 2 ) && !($p % 2)} {
        return [expr {$p < $q}]
    }
    if {!($p % 2)} {
        return 1
    }
    return -1
}

Can I use qsort with this comparator in some way using critcl, (or something else)?