How to pass int return type function in ON_COMMAND of BEGIN_MESSAGE_MAP

[Beginner_MFC]

When member function whose return type is int is placed inside the ON_COMMAND of BEGIN_MESSAGE_MAP, It shows error of invalid type conversion. Suggest whats the alternative for that or how can i pass int return function .

// MyFrame.h

afx_msg int func();

//MyFrame.cpp

BEGIN_MESSAGE_MAP (MyFrame, CFrameWnd)
ON_COMMAND (ID1,func)
END_MESSAGE_MAP()