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doc(runtime-c-api) Improve the README.md.

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This patch updates the `README.md` by adding badges, a Usage Section,
and a License Section. The Testing Section is slightly revamped.
This commit is contained in:
Ivan Enderlin
2019-03-06 14:11:12 +01:00
parent 28bb264266
commit f5ce1e8b60
1 changed files with 128 additions and 6 deletions
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lib/runtime-c-api/README.md
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<p align="center">
<a href="https://wasmer.io" target="_blank" rel="noopener noreferrer">
<img width="400" src="https://raw.githubusercontent.com/wasmerio/wasmer/master/logo.png" alt="Wasmer logo">
</a>
</p>
<p align="center">
<a href="https://circleci.com/gh/wasmerio/wasmer/">
<img src="https://img.shields.io/circleci/project/github/wasmerio/wasmer/master.svg" alt="Build Status">
</a>
<a href="https://github.com/wasmerio/wasmer/blob/master/LICENSE">
<img src="https://img.shields.io/github/license/wasmerio/wasmer.svg" alt="License">
</a>
<a href="https://spectrum.chat/wasmer">
<img src="https://withspectrum.github.io/badge/badge.svg" alt="Join the Wasmer Community">
</a>
<a href="https://crates.io/crates/wasm-bindgen">
<img src="https://img.shields.io/crates/d/wasmer-runtime-c-api.svg" alt="Number of downloads from crates.io">
</a>
<a href="https://docs.rs/wasm-bindgen">
<img src="https://docs.rs/wasmer-runtime-c-api/badge.svg" alt="Read our API documentation">
</a>
</p>
# Wasmer Runtime C API
## Generating header files
Run `make capi` from wasmer project root directory
Wasmer is a standalone JIT WebAssembly runtime, aiming to be fully
compatible with Emscripten, Rust and Go. [Learn
more](https://github.com/wasmerio/wasmer).
## Running tests
The tests can be run via `cargo test`, E.g. `cargo test -p wasmer-runtime-c-api -- --nocapture`
This crate exposes a C and a C++ API for the Wasmer runtime.
*Running manually*
`cmake . && make && make test` from the `lib/runtime-c-api/tests` directory
# Usage
The C and C++ header files can be found in the source tree of this
crate, respectively [`wasmer.h`][wasmer_h] and
[`wasmer.hh`][wasmer_hh]. They are automatically generated, and always
up-to-date in this repository.
Here is a simple example to use the C API:
```c
#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 argumen #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:
```sh
$ cargo test -- --nocapture
```
To run tests manually, enter the `lib/runtime-c-api/tests` directory
and run the following commands:
```sh
$ cmake .
$ make
$ make test
```
# License
Wasmer is primarily distributed under the terms of the [MIT
license][mit-license] ([LICENSE][license]).
[wasmer_h]: ./wasmer.h
[wasmer_hh]: ./wasmer.hh
[mit-license]: http://opensource.org/licenses/MIT
[license]: https://github.com/wasmerio/wasmer/blob/master/LICENSE