Problem that WebAssembly addresses : make the browser as generic as a computer, i.e. execute most programs
Principles
- But: Make it possible to reuse components coded in C, C++, Rust, etc. directly in the browser
- How: Convert C/CPP/Rust into LLVM representation
- Theoretical workflow: compile/export c/cpp file in wasm format, serve wasm to client browser, interact with wasm module from javascript code
```
flowchart LR;
    subgraph web[webservice]
        direction TB
        jscode[service.js]--interacts-->wasm
    end
    code[opencv.cpp]--export-->wasm[opencv.wasm]
    web--served-->client
```
- WebAssembly is not a virtual machine, it is processed
2 formats: Wat (text file), Wasm (binary)
Explorer: https://mbebenita.github.io/WasmExplorer/
JS / WA Interactions:
- Fetch the file and read it (binary)
- Use of the WebAssembly module (native) initialize WA module
- Instantiate module
- Then, whenever functions defined in the WA are called, the WA runtime will execute and deliver results to the JS runtime through a share memory
Limitations:
- No DOM interactions but possible to interact with external functions
- Interoperability between JS and WA only through integers and floats –> glue code
- No garbage collector (memory management is important)
- WA Runtime dependent on the browser

Quetions

Is it possible to export anything from a C/CPP/etc. program ? What are the limitations ?

References