`_free` is not defined runtime error

[jeswr]

Upgrading from emsdk 3.1.36 to 3.1.37 we have observed that we now get a _free is undefined error at runtime in particular environments, in particular trying to execute this line of code when no .data file is provided and instead we are generating a dl image in advance that gets loaded (for example see this sample project).

I suspect the removal of the global _free function for these environments occurred in this commit.

Is this an intentional breaking change? If so is there an easy fix on our end?

cc @rla @JanWielemaker

[sbc100]

I agree that the likely candidate is #18905.

If you want to use _malloc or _free outside of emscripten then you need to explicitly export them by adding them to EXPORTED_FUNCTIONS. e.g. -sEXPORTED_FUNCTIONS=_malloc,_free. This has been the case for a while now but I think perhaps the old reverse deps system was hiding the issue.

[jeswr]

Thanks for the info and quick response! Adding those to the list of exported functions indeed solved our issue.