wasmer/lib/runtime-c-api
2019-09-24 13:36:31 -07:00
..
src fix cargo check fail build 2019-09-24 09:08:55 +02:00
tests %lld -> %ld fixes cargo test compile error 2019-09-18 23:25:35 +02:00
build.rs feat(runtime-c-api) Build: Copy the C header files from OUT_DIR to CARGO_MANIFEST_DIR. 2019-03-06 10:58:40 +01:00
Cargo.toml Remove patch version in deps when not necessary 2019-09-20 16:11:09 -07:00
README.md lmproved READMEs to use Azure Pipelines badges and better lgo 2019-09-24 13:36:31 -07:00
wasmer.h chore(runtime-c-api) Update C & C++ headers. 2019-09-05 15:09:21 +02:00
wasmer.hh chore(runtime-c-api) Update C & C++ headers. 2019-09-05 15:09:21 +02:00

Wasmer logo

Build Status License Join the Wasmer Community Number of downloads from crates.io Read our API documentation

Wasmer Runtime C API

Wasmer is a standalone JIT WebAssembly runtime, aiming to be fully compatible with Emscripten, Rust and Go. Learn more.

This crate exposes a C and a C++ API for the Wasmer runtime.

Usage

The C and C++ header files can be found in the source tree of this crate, respectively wasmer.h and wasmer.hh. They are automatically generated, and always up-to-date in this repository.

Here is a simple example to use the C API:

#include <stdio.h>
#include "../wasmer.h"
#include <assert.h>
#include <stdint.h>

int main()
{
    // Read the Wasm file bytes.
    FILE *file = fopen("sum.wasm", "r");
    fseek(file, 0, SEEK_END);
    long len = ftell(file);
    uint8_t *bytes = malloc(len);
    fseek(file, 0, SEEK_SET);
    fread(bytes, 1, len, file);
    fclose(file);

    // Prepare the imports.
    wasmer_import_t imports[] = {};

    // Instantiate!
    wasmer_instance_t *instance = NULL;
    wasmer_result_t instantiation_result = wasmer_instantiate(&instance, bytes, len, imports, 0);

    assert(instantiation_result == WASMER_OK);

    // Let's call a function.
    // Start by preparing the arguments.

    // Value of argument #1 is `7i32`.
    wasmer_value_t argument_one;
    argument_one.tag = WASM_I32;
    argument_one.value.I32 = 7;

    // Value of argument #2 is `8i32`.
    wasmer_value_t argument_two;
    argument_two.tag = WASM_I32;
    argument_two.value.I32 = 8;

    // Prepare the arguments.
    wasmer_value_t arguments[] = {argument_one, argument_two};

    // Prepare the return value.
    wasmer_value_t result_one;
    wasmer_value_t results[] = {result_one};

    // Call the `sum` function with the prepared arguments and the return value.
    wasmer_result_t call_result = wasmer_instance_call(instance, "sum", arguments, 2, results, 1);

    // Let's display the result.
    printf("Call result:  %d\n", call_result);
    printf("Result: %d\n", results[0].value.I32);

    // `sum(7, 8) == 15`.
    assert(results[0].value.I32 == 15);
    assert(call_result == WASMER_OK);

    wasmer_instance_destroy(instance);

    return 0;
}

Testing

The tests can be run via cargo test, such as:

$ cargo test -- --nocapture

To run tests manually, enter the lib/runtime-c-api/tests directory and run the following commands:

$ cmake .
$ make
$ make test

License

Wasmer is primarily distributed under the terms of the MIT license (LICENSE).