Struct xwasmi::FuncInstance

pub struct FuncInstance(_);

Runtime representation of a function.

Functions are the unit of organization of code in WebAssembly. Each function takes a sequence of values as parameters and either optionally return a value or trap. Functions can call other function including itself (i.e recursive calls are allowed) and imported functions (i.e functions defined in another module or by the host environment).

Functions can be defined either:

• by a xwasm module,
• by the host environment and passed to a xwasm module as an import. See more in Externals.

Methods

impl FuncInstance

pub fn alloc_host(signature: Signature, host_func_index: usize) -> FuncRef

Allocate a function instance for a host function.

When this function instance will be called by the xwasm code, the instance of Externals will be invoked by calling invoke_index with specified host_func_index here. This call will be made with the signature provided here.

pub fn signature(&self) -> &Signature

Returns signature of this function instance.

This function instance can only be called with matching signatures.

pub fn invoke<E: Externals>(
    func: &FuncRef,
    args: &[RuntimeValue],
    externals: &mut E
) -> Result<Option<RuntimeValue>, Trap>

Invoke this function.

Errors

Returns Err if args types is not match function signature or if Trap at execution time occured.

pub fn invoke_resumable<'args>(
    func: &FuncRef,
    args: &'args [RuntimeValue]
) -> Result<FuncInvocation<'args>, Trap>

Invoke the function, get a resumable handle. This handle can then be used to start_execution. If a Host trap happens, caller can use resume_execution to feed the expected return value back in, and then continue the execution.

This is an experimental API, and this functionality may not be available in other WebAssembly engines.

Errors

Returns Err if args types is not match function signature.

Trait Implementations

impl Debug for FuncInstance

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.