Local use of WebAssembly

We compile a C++ source in wasm in order to locally run the target code.

1) Install Emscriptem

This program is simply downloaded from github and installed as explained in the article First WebAssembly program.

2) Write a small demonstration program in C ++

We will use the same example given in the installation tutorial.

Example:

#include <stdio.h>
    
int main() {
  puts("Hello, World!");
}

Save the program under the name hello.cpp

3) Compile to wasm

To generate the environment after opening the console:

./emsdk 

To generate the code:

emcc hello.cpp -o hello.wasm

This produces the following file:

hello.wasm

The hello.wasm file is a binary program. To view the content you can use wasm dump or wasm2asm or wasm-dis which is included in Emscriptem.

Local execution

To make the wasm code work locally, you can use Wasmer which is included in Emscriptem or installed separately.

wasmer hello.wasm

Which displays “Hello, World!”.