1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
// ignore-wasm32-bare no libc to test ffi with
#[link(name = "rust_test_helpers", kind = "static")]
extern {
fn rust_interesting_average(_: u64, ...) -> f64;
}
pub fn main() {
// Call without variadic arguments
unsafe {
assert!(rust_interesting_average(0).is_nan());
}
// Call with direct arguments
unsafe {
assert_eq!(rust_interesting_average(1, 10i64, 10.0f64) as i64, 20);
}
// Call with named arguments, variable number of them
let (x1, x2, x3, x4) = (10i64, 10.0f64, 20i64, 20.0f64);
unsafe {
assert_eq!(rust_interesting_average(2, x1, x2, x3, x4) as i64, 30);
}
// A function that takes a function pointer
unsafe fn call(fp: unsafe extern fn(u64, ...) -> f64) {
let (x1, x2, x3, x4) = (10i64, 10.0f64, 20i64, 20.0f64);
assert_eq!(fp(2, x1, x2, x3, x4) as i64, 30);
}
unsafe {
call(rust_interesting_average);
// Make a function pointer, pass indirectly
let x: unsafe extern fn(u64, ...) -> f64 = rust_interesting_average;
call(x);
}
}
|
