// PLAN-HTTPZ C2: an sx `callconv(.c)` function passes by name as a
// typed C function pointer — libc qsort drives an sx comparator.
#import "modules/std.sx";

clib :: #library "c";
qsort :: (base: [*]u8, nel: usize, width: usize, compar: (*void, *void) -> i32 callconv(.c)) extern clib;

cmp_i32 :: (a: *void, b: *void) -> i32 callconv(.c) {
    pa : *i32 = xx a;
    pb : *i32 = xx b;
    if pa.* < pb.* { return -1; }
    if pa.* > pb.* { return 1; }
    return 0;
}

main :: () -> i32 {
    arr : [5]i32 = .[ 4, 1, 5, 2, 3 ];
    qsort(xx @arr[0], 5, 4, cmp_i32);
    i := 0;
    while i < 5 {
        if arr[i] != cast(i32)(i + 1) { print("not sorted at {}\n", i); return 1; }
        i += 1;
    }
    print("qsort via sx comparator ok\n");
    return 0;
}