gistfile1.txt

use libc::{c_void, size_t};

#[nolink]
extern mod libc_ {
    fn qsort(base: *libc::c_void, nmemb: size_t, size: size_t,
             compar: *u8); // extern fn(a: *c_void, b: *c_void) -> int
}

fn compare<T: cmp::Ord>(a: *c_void, b: *c_void) -> int unsafe {
    let (a_, b_) = (&*(a as *T), &*(b as *T));
    if *a_ < *b_ {
        -1
    } else if *a_ > *b_ {
        1
    } else {
        0
    }
}

extern fn compare_str(a: *c_void, b: *c_void) -> int {
    compare::<~str>(a, b)
}


fn qsort<T>(v: &[mut T]) {
    do vec::as_mut_buf(v) |base, nmemb| {
        libc_::qsort(
            base as *c_void,
            nmemb as size_t,
            sys::size_of::<T>() as size_t,
            compare_str);
    }
}


fn main() {
    let mut args = os::args();
    qsort(args);
    io::println(fmt!("%?", args));
}