[C] Winapi Call Dynamically and easily

[bugficks]

youre mixing stuff up. that GetModuleHandle/LoadLibrary is from original post and thats C, functor in C w/ destructor?
my c++14 version keeps lib ref count constant, thats the sole purpose of the map (what you call 'cache')
also you want to keep lib loaded as dlls might have some init/deinit functions or keep some state between calls.

so if you want to fix version from original post use GetModuleHandleEx and call FreeLibrary later only if GetModuleHandleEx returned a valid handle.
for my c++ version just use thread_local on map like i ve already said before. this will also fix if a dll uses DLL_THREAD_ATTACH which a mutex does not.