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