emscripte to Javascript question


Compiling a C program with Emscripten and using the resulting file in vanilla JavaScript involves several steps. Here’s a straightforward process:

1. Install Emscripten
First, you need to install Emscripten. Follow these steps:

Download and Install Emscripten:
Go to the Emscripten official site and follow the installation instructions.
Ensure you have Python and Git installed as prerequisites.
2. Write Your C Program
Create a simple C program, for example, hello.c:

c
Αντιγραφή κώδικα
#include <stdio.h>

int main() {
    printf("Hello, Emscripten!\n");
    return 0;
}
3. Compile the C Program
Use Emscripten’s emcc command to compile your C program into WebAssembly (or JavaScript). Open your terminal and run:

bash
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emcc hello.c -o hello.js
This command does the following:

Compiles hello.c.
Outputs hello.js and hello.wasm (if generating WebAssembly).
4. Use the Generated Files in HTML
You can now use the generated JavaScript and WebAssembly files in an HTML file. Create an index.html file:

html
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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Emscripten Example</title>
    <script src="hello.js"></script>
</head>
<body>
    <h1>Emscripten Example</h1>
    <script>
        // Wait for the module to be ready
        Module.onRuntimeInitialized = function() {
            // Call the main function from C
            Module._main();
        };
    </script>
</body>
</html>
5. Serve Your Files
Emscripten-generated files often need to be served from a web server due to WebAssembly restrictions. You can use a simple server for testing:

bash
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# If you have Python installed
python -m http.server
Navigate to http://localhost:8000 in your browser to view your page.

6. Check Output
Open the browser's console to see the output from your C program. You should see "Hello, Emscripten!" printed.

Summary
Install Emscripten.
Write your C code.
Compile using emcc.
Create an HTML file to load the generated JavaScript.
Serve the files and check the output in the browser console.
This is a basic example to get you started. Emscripten supports many additional features, including more complex C libraries and APIs, so you can explore those as you become more comfortable!