Expand description

Types and traits for interfacing between the host and the wasm runtime.


  • pub use wasmtime;
  • pub use anyhow;



  • A wrapper which merges two sets of host functions, and allows the second set to override the host functions from the first set.
  • Type to represent a pointer in wasm at the host.
  • The Signature of a function


  • Typed value that can be returned from a function.
  • Values supported by Substrate on the boundary between host/Wasm.
  • Value types supported by Substrate on the boundary between host/Wasm.


  • Something that provides a function implementation on the host for a wasm function.
  • Context used by Function to interact with the allocator and the memory of the wasm instance.
  • A trait used to statically register host callbacks with the WASM executor, so that they call be called from within the runtime with minimal overhead.
  • Something that provides implementations for host functions.
  • Something that can be converted into a wasm compatible Value.
  • A trait that requires RefUnwindSafe when feature = std.
  • Something that can be wrapped in a wasm Pointer.
  • Something that can may be created from a wasm Value.
  • A trait for types directly usable at the WASM FFI boundary without any conversion at all.

Type Aliases§

  • Result type used by traits in this crate.
  • The word size used in wasm. Normally known as usize in Rust.