about c++ exceptions. func() throw()

c++ exception throw
user34537 picture user34537 · Mar 2, 2009 · Viewed 9.8k times · Source

i am reading this page http://www.cplusplus.com/doc/tutorial/exceptions.html it says if i write function() throw(); no exceptions can be thrown in that function. I tried in msvc 2005 writing throw(), throw(int), throw() and nothing at all. each had the exact same results. Nothing. I threw int, char*, another type and it was all caught the same way. It looks like throw doesnt affect it at all. What does function() throw() actually do?

Answer

Nemanja Trifunovic picture Nemanja Trifunovic · Mar 2, 2009

See this article for details on C++ exception specifications and Microsoft's implementation:

Microsoft Visual C++ 7.1 ignores exception specifications unless they are empty. Empty exception specifications are equivalent to __declspec(nothrow), and they can help the compiler to reduce code size.

[...] If it sees an empty exception specification, it will assume you know what you are doing and optimize away the mechanics for dealing with exceptions. If your function throws anyway - well, shame on you. Use this feature only if you are 100% positive your function does not throw and never will.

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