Initialization problems occur when the application calls the Win32 API before Winelib has been initialized. How can this happen?
Winelib is initialized by the application's main before it calls the regular WinMain. But, in C++, the constructors of static class variables are called before the main (by the module's initializer). So if such a constructor makes calls to the Win32 API, Winelib will not be initialized at the time of the call and you may get a crash. This problem is much more frequent in C++ because of these class constructors but could also, at least in theory, happen in C if you were to specify an initializer making calls to Winelib. But of course, now that you are aware of this problem you won't do it :-).
Further compounding the problem is the fact that Linux's (GNU's?) current dynamic library loader does not call the module initializers in their dependency order. So even if Winelib were to have its own initializer there would be no garantee that it would be called before the initializer of the library containing this static variable. Finally even if the variable is in a library that your application links with, that library's initializer may be called before Winelib has been initialized. One such library is the MFC.
The current workaround is to move all the application's code in a library and to use a small Winelib application to dynamically load this library. Tus the initialization sequence becomes:
the wrapper application starts.
its empty initializer is run.
its main is run. Its first task is to initialize Winelib.
it then loads the application's main library, plus all its dependent libraries.
which triggers the execution of all these libraries initializers in some unknown order. But all is fine because Winelib has already been initialized anyway.
finally the main function calls the WinMain of the application's library.
This may sound complex but Winemaker makes it simple. Just specify --wrap or --mfc on the command line and it will adapt its makefiles to build the wrapper and the application library.