7a1b7cdf92
Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.
74 lines
2.2 KiB
Rust
74 lines
2.2 KiB
Rust
//! 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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#[cfg(not(feature = "old-x86-backend"))]
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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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// Note that this example is not supported in the off-by-default feature of the
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// old x86 compiler backend for Cranelift. Wasmtime's default configuration
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// supports this example, however.
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#[cfg(feature = "old-x86-backend")]
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fn main() -> Result<()> {
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Ok(())
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}
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