Module wasmer_c_api::error

Utilities to read errors.

Only one error can be registered at a time. Error are registered by Rust only, and are usually read by C or C++.

Reading an error from C or C++ happens in 2 steps: Getting the error’s length with wasmer_last_error_length, and then reading the actual error with wasmer_last_error_message.

Example

int main() {
    // Create an invalid WebAssembly module from a WAT definition,
    // it will generate an error!
    wasm_byte_vec_t wat;
    wasmer_byte_vec_new_from_string(&wat, "(foobar)");
    wasm_byte_vec_t wasm;
    wat2wasm(&wat, &wasm);

    int error_length = wasmer_last_error_length();

    // There is an error!
    assert(error_length > 0);

    char *error_message = malloc(error_length);
    wasmer_last_error_message(error_message, error_length);
    printf("Error message: %s\n", error_message);

    // Side note: The error has now been cleared on the Rust side!
    assert(wasmer_last_error_length() == 0);

    // Free everything.
    free(error_message);
    wasm_byte_vec_delete(&wasm);
    wasm_byte_vec_delete(&wat);

    return 0;
}

Functions

• update_last_error
  Rust function to register a new error.
• wasmer_last_error_length
  Gets the length in bytes of the last error if any, zero otherwise. This includes th NUL terminator byte.
• wasmer_last_error_message^⚠
  Gets the last error message if any into the provided buffer buffer up to the given length.