Use the FreeLibrary32W function in 16-bit code to free a 32-bit thunk DLL that it had previously loaded with the LoadLibraryEx32W function.
BOOL FAR PASCAL FreeLibrary32W(
DWORD hInst // handle to loaded library module
);
The system does not do any cleanup of 32-bit thunk DLLs when the 16-bit application exits. The 16-bit application or DLL must free the 32-bit thunk DLL when it is finished using it.
Windows 95 and Windows 98: This function releases the Win16Mutex. If this function is called from a 16-bit DLL, it can be reentered as soon as the 32-bit DLL entry-point function is called. This happens when another 32-bit process thunks to the 16-bit DLL or when another 16-bit DLL calls this 16-bit DLL. However, if this function is called in a 16-bit application and the 32-bit DLL entry-point function does not yield, the function is not reentered.