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
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
//! This is an example of working with multi-value modules and dealing with
//! multi-value functions.
//!
//! Note that the `Func::wrap*` interfaces cannot be used to return multiple
//! values just yet, so we need to use the more dynamic `Func::new` and
//! `Func::call` methods.
// You can execute this example with `cargo run --example multi`
use anyhow::Result;
fn main() -> Result<()> {
use wasmtime::*;
println!("Initializing...");
let engine = Engine::default();
let mut store = Store::new(&engine, ());
// Compile.
println!("Compiling module...");
let module = Module::from_file(&engine, "examples/multi.wat")?;
// Create a host function which takes multiple parameters and returns
// multiple results.
println!("Creating callback...");
let callback_func = Func::wrap(&mut store, |a: i32, b: i64| -> (i64, i32) {
(b + 1, a + 1)
});
// Instantiate.
println!("Instantiating module...");
let instance = Instance::new(&mut store, &module, &[callback_func.into()])?;
// Extract exports.
println!("Extracting export...");
let g = instance.get_typed_func::<(i32, i64), (i64, i32)>(&mut store, "g")?;
// Call `$g`.
println!("Calling export \"g\"...");
let (a, b) = g.call(&mut store, (1, 3))?;
println!("Printing result...");
println!("> {a} {b}");
assert_eq!(a, 4);
assert_eq!(b, 2);
// Call `$round_trip_many`.
println!("Calling export \"round_trip_many\"...");
let round_trip_many = instance
.get_typed_func::<
(i64, i64, i64, i64, i64, i64, i64, i64, i64, i64),
(i64, i64, i64, i64, i64, i64, i64, i64, i64, i64),
>
(&mut store, "round_trip_many")?;
let results = round_trip_many.call(&mut store, (0, 1, 2, 3, 4, 5, 6, 7, 8, 9))?;
println!("Printing result...");
println!("> {results:?}");
assert_eq!(results, (0, 1, 2, 3, 4, 5, 6, 7, 8, 9));
Ok(())
}
|
