Emscripten is a WebAssembly toolchain and compiler backend that transforms C and C++ source code into WebAssembly bytecode. It serves as a framework for porting native applications and libraries to web browsers and server runtimes by translating LLVM intermediate representation into optimized WebAssembly modules.
The system specializes in porting native graphical standards, such as OpenGL and SDL2, by mapping native graphics API calls to browser-compatible WebGL commands. This allows complex visual applications and native desktop software to be deployed as portable web formats.
The toolchain includes a compatible C standard library, a virtual file system that emulates POSIX-compliant I/O operations, and a dynamic linker simulation. It also generates JavaScript glue code to manage memory allocation and function calls between the WebAssembly module and the browser environment.
