Learn WebAssembly

Calling imported functions in C/C++

You need to define the JavaScript function you passed into importObj.env within the C/C++ code that utilizes it. The function signature must match what you passed in. The following example demonstrates this in greater detail. Here's the JavaScript code that interacts with the compiled C file (index.html):

// index.html <script> contentsconst env = {  _logAndMultiplyTwoNums: (num1, num2) => {    const result = num1 * num2;    console.log(result);    return result;  },};loadWasm('main.wasm', { env })  .then(({ instance }) => {    const result = instance.exports._callMultiply(5.5, 10);    console.log(result);    // 55 is logged to the console twice  });

This is the contents of main.c, which is compiled to main.wasm and used within ...