wasm-micro-runtime/doc/wasm_c_api.md

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# wasm-c-api introduction
wasm-c-api is an engine-agnostic API to embed a WASM engine.
In wasm-micro-runtime, it's provided by the header file `wasm_c_api.h`.
Its functionalities are overlapping with `wasm_export.h`, which is
a native API of wasm-micro-runtime. An embedder is supposed to pick
one of these APIs, rather than mixing both of them.
All samples come from the commit 340fd9528cc3b26d22fe30ee1628c8c3f2b8c53b
of [wasm-c-api](https://github.com/WebAssembly/wasm-c-api).
Developer can learn these _APIs_ from
[wasm.h](https://github.com/WebAssembly/wasm-c-api/blob/master/include/wasm.h).
And here are [examples](https://github.com/WebAssembly/wasm-c-api/tree/master/example) which
are helpful.
## FYI
- The thread model of _wasm_c_api_ is
- An `wasm_engine_t` instance may only be created once per process
- Every `wasm_store_t` and its objects may only be accessed in a single thread
- `wasm_engine_new`, `wasm_engine_new_with_config`, `wasm_engine_new_with_args`,
`wasm_engine_delete`should be called in a thread-safe environment. Such
behaviors are not recommended, and please make sure an appropriate calling
sequence if it has to be.
- call `wasm_engine_new` and `wasm_engine_delete` in different threads
- call `wasm_engine_new` or `wasm_engine_delete` multiple times in
different threads
## unspported list
Currently WAMR supports most of the APIs, the unsupported APIs are listed as below:
- References
```c
WASM_API_EXTERN own wasm_shared_##name##_t* wasm_##name##_share(const wasm_##name##_t*);
WASM_API_EXTERN own wasm_##name##_t* wasm_##name##_obtain(wasm_store_t*, const wasm_shared_##name##_t*);
```
- Several Module APIs
```c
WASM_API_EXTERN void wasm_module_serialize(const wasm_module_t*, own wasm_byte_vec_t* out);
WASM_API_EXTERN own wasm_module_t* wasm_module_deserialize(wasm_store_t*, const wasm_byte_vec_t*);
```
Currently growing a table or memory by wasm opcode is supported and it is not supported to grow them
by host-side function callings.
- Table Grow APIs
```c
WASM_API_EXTERN bool wasm_table_grow(wasm_table_t*, wasm_table_size_t delta, wasm_ref_t* init);
```
- Memory Grow APIs
```c
WASM_API_EXTERN bool wasm_memory_grow(wasm_memory_t*, wasm_memory_pages_t delta);
```