Representation of a WebAssembly externref value. More...

#include <wasmtime.hh>

Public Member Functions
	ExternRef (wasmtime_externref_t val)
	Creates a new `ExternRef` directly from its C-API representation.

template<typename T >
	ExternRef (Store::Context cx, T val)

ExternRef	clone (Store::Context cx)
	Creates a new `ExternRef` which is separately rooted from this one.

std::any &	data (Store::Context cx)
	Returns the underlying host data associated with this `ExternRef`.

void	unroot (Store::Context cx)

const wasmtime_externref_t *	raw () const

Detailed Description

Representation of a WebAssembly externref value.

This class represents an value that cannot be forged by WebAssembly itself. All ExternRef values are guaranteed to be created by the host and its embedding. It's suitable to place private data structures in here which WebAssembly will not have access to, only other host functions will have access to them.

Note that ExternRef values are rooted within a Store and must be manually unrooted via the unroot function. If this is not used then values will never be candidates for garbage collection.

Examples: externref.cc.

Constructor & Destructor Documentation

◆ ExternRef()

template<typename T >

wasmtime::ExternRef::ExternRef	(	Store::Context	cx,
		T	val
	)

inlineexplicit

Creates a new externref value from the provided argument.

Note that val should be safe to send across threads and should own any memory that it points to. Also note that ExternRef is similar to a std::shared_ptr in that there can be many references to the same value.

Member Function Documentation

◆ raw()

const wasmtime_externref_t * wasmtime::ExternRef::raw ( ) const

inline

Returns the raw underlying C API value.

This class still retains ownership of the pointer.

◆ unroot()

void wasmtime::ExternRef::unroot ( Store::Context cx )