Strings: CString Exception Cleanup
In previous versions of MFC, it was important that you clean up CString objects after use. With MFC version 3.0 and later, explicit cleanup is no longer necessary.
Under the C++ exception handling mechanism that MFC now uses, you do not have to worry about cleanup after an exception. For a description of how C++ "unwinds" the stack after an exception is caught, see the try, catch, and throw statements. Even if you use the MFC TRY/CATCH macros instead of the C++ keywords try and catch, MFC uses the C++ exception mechanism underneath, so you still do not need to clean up explicitly.