tag.h File Reference

Wasmtime APIs for WebAssembly exception tag types. More...

#include <stddef.h>
#include <wasm.h>

Go to the source code of this file.

Macros
#define	WASMTIME_EXTERNTYPE_TAG   4
	Value returned by wasm_externtype_kind for exception tags. More...

Typedefs
typedef struct wasmtime_tagtype_t	wasmtime_tagtype_t
	Opaque type representing a WebAssembly exception tag type. More...

Functions
WASM_API_EXTERN wasmtime_tagtype_t *	wasmtime_tagtype_new (wasm_engine_t *engine, const wasm_functype_t *functype)
	Creates a new tag type from the given function type. More...
WASM_API_EXTERN void	wasmtime_tagtype_delete (wasmtime_tagtype_t *)
	Deletes a wasmtime_tagtype_t.
WASM_API_EXTERN wasmtime_tagtype_t *	wasmtime_tagtype_copy (const wasmtime_tagtype_t *)
	Returns a copy of the given wasmtime_tagtype_t (caller owns the result).
WASM_API_EXTERN wasm_functype_t *	wasmtime_tagtype_functype (const wasmtime_tagtype_t *)
	Returns the function type describing this tag's exception payload. More...
WASM_API_EXTERN wasm_externtype_t *	wasmtime_tagtype_as_externtype (wasmtime_tagtype_t *)
	Converts a wasmtime_tagtype_t to a wasm_externtype_t (borrowed).
WASM_API_EXTERN const wasm_externtype_t *	wasmtime_tagtype_as_externtype_const (const wasmtime_tagtype_t *)
	Converts a const wasmtime_tagtype_t to a const wasm_externtype_t (borrowed).
WASM_API_EXTERN wasmtime_tagtype_t *	wasmtime_externtype_as_tagtype (wasm_externtype_t *)
	Converts a wasm_externtype_t to a wasmtime_tagtype_t, or NULL if not a tag.
WASM_API_EXTERN const wasmtime_tagtype_t *	wasmtime_externtype_as_tagtype_const (const wasm_externtype_t *)
	Converts a const wasm_externtype_t to a const wasmtime_tagtype_t, or NULL if not a tag.

Detailed Description

Wasmtime APIs for WebAssembly exception tag types.

This header defines the C API for wasmtime_tagtype_t, the type descriptor for WebAssembly exception tags (wasm exception-handling proposal). Because wasm.h is vendored from the upstream wasm-c-api repository and does not yet include tag-type support, the declarations live here instead.

Macro Definition Documentation

WASMTIME_EXTERNTYPE_TAG

#define WASMTIME_EXTERNTYPE_TAG   4

Value returned by wasm_externtype_kind for exception tags.

This constant extends the WASM_EXTERN_* range from wasm.h (0–3) with tag support. It is distinct from WASMTIME_EXTERN_SHAREDMEMORY (which is a discriminant for the runtime wasmtime_extern_t union in wasmtime/extern.h).

Typedef Documentation

wasmtime_tagtype_t

typedef struct wasmtime_tagtype_t wasmtime_tagtype_t

Opaque type representing a WebAssembly exception tag type.

A tag type is described by a function type whose parameters are the exception payload types and whose results are the tag's result types (currently always empty, but reserved for the stack-switching proposal).

Function Documentation

wasmtime_tagtype_functype()

WASM_API_EXTERN wasm_functype_t * wasmtime_tagtype_functype

(

const wasmtime_tagtype_t *

)

Returns the function type describing this tag's exception payload.

The caller owns the returned wasm_functype_t and must free it with wasm_functype_delete.

wasmtime_tagtype_new()

WASM_API_EXTERN wasmtime_tagtype_t * wasmtime_tagtype_new	(	wasm_engine_t *	engine,
		const wasm_functype_t *	functype
	)

Creates a new tag type from the given function type.

The function type describes the exception payload: its parameters are the tag's exception payload types and its results are the tag's result types. engine is used to resolve functype if it has not yet been interned.

Returns an owned wasmtime_tagtype_t that must be freed with wasmtime_tagtype_delete.