# [−] [src] Struct wasmi::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 wasm module,
- by the host environment and passed to a wasm module as an import. See more in `Externals`.

## Methods

### `impl FuncInstance` [src]

#### `pub fn alloc_host(signature: Signature, host_func_index: usize) -> FuncRef` [src]

Allocate a function instance for a host function.

When this function instance will be called by the wasm 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` [src]

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>` [src]

Invoke this function.

# Errors

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

#### `pub fn invoke_with_stack<E: Externals>(
func: &FuncRef,
args: &[RuntimeValue],
externals: &mut E,
stack_recycler: &mut StackRecycler
) -> Result<Option<RuntimeValue>, Trap>` [src]

Invoke this function using recycled stacks.

# Errors

Same as `invoke`.

#### `pub fn invoke_resumable<'args>(
func: &FuncRef,
args: impl Into<Cow<'args, [RuntimeValue]>>
) -> Result<FuncInvocation<'args>, Trap>` [src]

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` [src]

#### `fn fmt(&self, f: &mut Formatter) -> Result` [src]

Formats the value using the given formatter. Read more

## Auto Trait Implementations

### `impl !Send for FuncInstance`

### `impl !Sync for FuncInstance`

### `impl Unpin for FuncInstance`

### `impl !UnwindSafe for FuncInstance`

### `impl !RefUnwindSafe for FuncInstance`

## Blanket Implementations

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `fn into(self) -> U` [src]

Performs the conversion.

### `impl<T> From<T> for T` [src]

#### `fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `fn borrow(&self) -> &T` [src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `fn borrow_mut(&mut self) -> &mut T` [src]

Mutably borrows from an owned value. Read more

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

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