Calling A Function Pointer With Emscripten

With Emscripten, is it possible to call a function pointer (thus, a number) from JavaScript? The signature of the function is variable, so I can't write a helper and be done. To il

Solution 1:

You can call a C function pointer from JS using Runtime.dynCall. See for example

https://github.com/kripken/emscripten/blob/ee17f05c0a45cad728ce0f215f2d2ffcdd75434b/src/library_browser.js#L715

The arguments are (type signature, pointer, array of arguments). For example, the type 'vi' means return void, receive one integer parameter. This corresponds to FUNCTION_TABLE_vi which you can see in the generated code.

Solution 2:

I would create a C function:

voidcall_feature_activator(int activator, float in_val) {
  ((void(*)(float))activator) (in_val);
}

You can then call the function on the JavaScript side to trigger your activator call and it will handle casting back to a function pointer and calling it.