xref: /wasmtime-44.0.1/examples/linking.rs (revision 2b00a541)
1 //! Example of instantiating two modules which link to each other.
2 
3 // You can execute this example with `cargo run --example linking`
4 
5 use anyhow::Result;
6 use wasi_common::sync::WasiCtxBuilder;
7 use wasmtime::*;
8 
9 fn main() -> Result<()> {
10     let engine = Engine::default();
11 
12     // First set up our linker which is going to be linking modules together. We
13     // want our linker to have wasi available, so we set that up here as well.
14     let mut linker = Linker::new(&engine);
15     wasi_common::sync::add_to_linker(&mut linker, |s| s)?;
16 
17     // Load and compile our two modules
18     let linking1 = Module::from_file(&engine, "examples/linking1.wat")?;
19     let linking2 = Module::from_file(&engine, "examples/linking2.wat")?;
20 
21     // Configure WASI and insert it into a `Store`
22     let wasi = WasiCtxBuilder::new()
23         .inherit_stdio()
24         .inherit_args()?
25         .build();
26     let mut store = Store::new(&engine, wasi);
27 
28     // Instantiate our first module which only uses WASI, then register that
29     // instance with the linker since the next linking will use it.
30     let linking2 = linker.instantiate(&mut store, &linking2)?;
31     linker.instance(&mut store, "linking2", linking2)?;
32 
33     // And with that we can perform the final link and the execute the module.
34     let linking1 = linker.instantiate(&mut store, &linking1)?;
35     let run = linking1.get_typed_func::<(), ()>(&mut store, "run")?;
36     run.call(&mut store, ())?;
37     Ok(())
38 }
39