Struct wasmedge_sys::instance::global::Global

pub struct Global { /* private fields */ }

Defines a WebAssembly global variable, which stores a single value of the given type and a flag indicating whether it is mutable or not.

Implementations

impl Global

pub fn create(ty: &GlobalType, val: WasmValue) -> WasmEdgeResult<Self>

Creates a new Global instance to be associated with the given GlobalType and WasmValue.

The type of the given WasmValue must be matched with GlobalType; otherwise, it causes a failure. For example, WasmValue::I32(520) conflicts with a GlobalType with a value type defined as ValType::F32.

Errors

• If fail to create the Global instance, then WasmEdgeError::Global(GlobalError::Create)(crate::error::GlobalError) is returned.

pub fn ty(&self) -> WasmEdgeResult<GlobalType>

Returns the underlying wasm type of a Global instance.

Errors

If fail to get the type, then an error is returned.

pub fn get_value(&self) -> WasmValue

Returns the value of the Global instance.

pub fn set_value(&mut self, val: WasmValue) -> WasmEdgeResult<()>

Sets the value of the Global instance.

Notice that only the Global instance of Mutability::Var type can be set a new value. Setting a new value for a Global of Mutability::Const causes a failure.

Argument

• val - The new wasm value to be set.

Errors

If fail to set value, then an error is returned.

Example

use wasmedge_sys::{Global, GlobalType, WasmValue};
use wasmedge_types::{ValType, Mutability};

// create a GlobalType instance
let ty = GlobalType::create(ValType::F32, Mutability::Var).expect("fail to create a GlobalType");
// create a Global instance
let mut global = Global::create(&ty, WasmValue::from_f32(3.1415)).expect("fail to create a Global");

global.set_value(WasmValue::from_f32(314.15)).expect("fail to set a new value for a Global");
assert_eq!(global.get_value().to_f32(), 314.15);

pub fn as_ptr(&self) -> *const WasmEdge_GlobalInstanceContext

Available on crate feature ffi only.

Provides a raw pointer to the inner global context.

Trait Implementations

impl Clone for Global

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Global

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

Formats the value using the given formatter.

impl Drop for Global

fn drop(&mut self)

Executes the destructor for this type.