Re: try...catch vs TRY...CATCH
On Tue, 11 Jul 2006 16:23:01 +0200, Ulrich Eckhardt
<eckhardt@satorlaser.com> wrote:
In idiomatic C++, you throw exceptions by value, which is why they must be
copy-constructible. Therefore, again in idiomatic C++, you never throw
pointers no new'ed exceptions that you then have to delete.
Other than that, the TRY/CATCH/etc macros from MFC are (in newer versions of
the environment) implemented in terms of the C++ try/catch mechanisms. So,
everything you can do with TRY/CATCH/etc can be done with try/catch. This
doesn't mean you should, as it only causes confusion to the next person
reading it.
I don't think this causes any confusion at all:
catch (CException* p)
{
...
p->Delete(); // or throw;
}
In fact, it will save you some time if you ever find yourself in a
heterogeneous exception environment, because you won't have to rewrite all
the macros. FWIW, ISTR reading documentation that states that the keywords
should be considered preferred to the macros.
The only real problem with using try/catch and MFC exceptions is with
catch(...). If it's possible for catch(...) to catch an MFC exception, it
must rethrow, or you run the risk of a memory leak, since you can't call
Delete(). But note that the exceptions thrown by functions like
AfxThrowMemoryException() have static storage duration, so Delete() amounts
to a no-op for them. This is why you must call Delete() instead of using
the delete operator.
Finally, the heterogeneous exception environment mentioned above introduces
some new problems into MFC programs, which I talk about here:
http://members.cox.net/doug_web/eh.htm#Q6
--
Doug Harrison
Visual C++ MVP