https://github.com/evanw/emscripten-library-generator

A library generator for the emscripten compiler
https://github.com/evanw/emscripten-library-generator

Last synced: 2 months ago
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A library generator for the emscripten compiler

• Host: GitHub
• URL: https://github.com/evanw/emscripten-library-generator
• Owner: evanw
• License: mit
• Created: 2013-12-22T03:25:06.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2025-03-31T23:21:17.000Z (2 months ago)
• Last Synced: 2025-03-31T23:28:42.089Z (2 months ago)
• Language: JavaScript
• Size: 14.6 KB
• Stars: 39
• Watchers: 3
• Forks: 9
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# Emscripten Library Generator

This packages normal JavaScript libraries into emscripten's strange, undocumented library format which can be passed to the emscripten compiler with the `--js-library` flag. It can also be used to automatically populate the emscripten setting `EXPORTED_FUNCTIONS` using the `--unresolved` flag. It works by computing dependency and initialization information for global symbols and automatically prefixing all resolved global symbols with an underscore to match emscripten's output. Top-level statements other than variable or function declarations are not supported (put initialization into a JavaScript function that is called as the first statement inside main() in C++).

## Library Generation

Terminal commands:

    npm install -g emscripten-library-generator

    emscripten-library-generator input1.js input2.js ... > library.js

Example input:

    var handles = {};

    function Foo(data) {

      this.data = data;

    }

    function Foo_new(ptr, data) {

      handles[ptr] = new Foo(data);

    }

    function Foo_delete(ptr) {

      delete handles[ptr];

    }

Example output:

    mergeInto(LibraryManager.library, {

        handles: {},

        Foo: function (data) {

            this.data = data;

        },

        Foo_new__deps: [

            'handles',

            'Foo'

        ],

        Foo_new: function (ptr, data) {

            _handles[ptr] = new _Foo(data);

        },

        Foo_delete__deps: ['handles'],

        Foo_delete: function (ptr) {

            delete _handles[ptr];

        }

    });

Usage from C++:

    struct Foo;

    extern "C" {

      void Foo_new(Foo *foo, int data);

      void Foo_delete(Foo *foo);

    }

    

    struct Foo {

      Foo(int data) : _data(data) {

        Foo_new(this, data);

      }

      ~Foo() {

        Foo_delete(this);

      }

      

    private:

      int _data;

    };

## Unresolved Symbols

Finds all unresolved symbols that start with an underscore, which are assumed to be `extern "C"` functions in C++. If these symbol names are not specified, the emscripten compiler may omit those functions as dead code and JavaScript won't be able to access them.

Terminal commands (notice the `--unresolved` flag):

    npm install -g emscripten-library-generator

    emscripten-library-generator --unresolved input1.js input2.js ... > unresolved.json

Example input:

    var timeout = 0;

    function wait(value, delay) {

      if (timeout) {

        clearTimeout(timeout);

        _interrupted(value);

      }

      timeout = setTimeout(function() {

        _success(value);

        timeout = 0;

      }, delay);

    }

Example output:

    ["_interrupted","_success"]

Usage from C++:

    extern "C" {

      void wait(int value, int delay);

      void interrupted(int value) {

        printf("interrupted: %d\n", value);

      }

      void success(int value) {

        printf("success: %d\n", value);

      }

    }