How would you tell if you needed a module reference?

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That would be it. That happens when the linker doesn’t find the definition of something you’re using, in this case that would be because it was defined in another module that you don’t have listed as a dependency.

The module system is specific to Unreal but here is the gist of what’s wrong.

int square(int);

int main()
{
    int value = square(3);
}

If I compile this from the command line with MSVC

cl main.cpp

I get this error

unresolved external symbol "int __cdecl square(int)" (?square@@YAHH@Z) referenced in function _main

as it compiled just fine but when it came to linking the linker didn’t find the definition. This could just be because you forgot to define it or was defined somewhere else and you didn’t tell the linker about it. If I had a square.cpp that was separately compiled into a static library then that would be

cl main.cpp square.lib

So when you get that unresolved external symbol error it’s either, you forgot to define something or you’re missing a module dependency

(Note: you don’t have to define something you don’t use, though “you” here also means generated code from Unreal)

The documentation tells you what module something is part of except here as GameplayTasks is only actually needed on Windows. Maybe other platforms already have that as a dependency or maybe the Windows code uses a different code path that has that as a dependency, I’m not sure.

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