Handling "Exception: wasi proc exit"

[nchamzn]

Hi,

After this change, is an embedder expected to check the exception matches "Exception: wasi proc exit" as iwasm now does to validate if there was an error? How stable can we expect that string to be?

Thanks.

[wenyongh]

Hi, "wasi proc exit" is a normal behavior and the exception will be cleared by runtime before wasi app main function returns.

wasm-micro-runtime/core/iwasm/common/wasm_application.c

Lines 132 to 137 in 8b37048

	WASMModuleInstance *inst = (WASMModuleInstance *)module_inst;
	if (!ret && strstr(inst->cur_exception, wasi_proc_exit_exception)) {
	inst->cur_exception[0] = 0;
	ret = true;
	}
	return ret;

Please use wasm_runtime_get_exception to check whether there was exception thrown.

[nchamzn]

Hi, sorry - I meant as an embedder so not using iwasm. I think at the moment if we call a wasm function then we are required to check for an exception and then ignore it if it matches "Exception: wasi proc exit"?

[wenyongh]

Hi, yes, the "wasi proc exit" is only thrown when the wasm app is a wasi module, and it is cleared by runtime if the function to call is "_start" function and developer uses wasm_application_execute_main to call it. If developer calls other functions or calls "_start" function without using wasm_application_execute_main, normally he should ignore the "wasi proc exit" by himself.