Won't -Wreturn suffice? Rich. > On Thu, 3 Apr 2003, Fred Ma wrote: > > > Hello, > > > > I just spent a great number of hours chasing down a > > bug that showed itself on g++ on cygwin, but not on > > g++ on solaris2.5.8. What did it turn out to be? > > > > I had a class member function that returned an > > object, according to the prototype. Also according > > to the function definition. But, the function body > > didn't actually contain a return statement. Like > > SomeFunc() below: > > > > SomeClass{ > > // ... > > ReturnType SomeFunc( SomeArgs); > > Void AnotherFunc(void); > > // ... > > } > > > > ReturnType SomeClass::SomeFunc(SomeArgs){ > > // Do stuff, > > // No return statement > > } > > > > void SomeClass::AnotherFunc(void){ > > // Do stuff... > > > > // Call SomeFunc(): > > SomeFunc(SomeArgs); > > } > > > > This caused corruption that resulted in memory > > access violations, even though SomeFunc's > > returned object isn't [EMAIL PROTECTED] point where it > > is invoked. The memory violations didn't happen > > at the point where SomeFunc() was invoked, > > either, but in a later step in the code. > > > > The frustrating thing is that the compiler didn't > > [EMAIL PROTECTED] about the discrepancy between > > the lack of a return statement, even though the > > function needed one. I personally find this kind > > of thing quite common when I reorganize my > > code e.g. moving functionality in and out of class > > member functions; that is, the finger details like > > return types and argument lists change so that > > it's easy to miss. > > > > Shouldn't compilers be smart enough to > > not create code that corrupts when it is pretty > > straighforward to realize that (1) there is an > > obvious discrepancy, for which a warning can > > easily be issued, or (2) realize that the return > > type really isnt' being used and compile it in a > > way that doesn't create memory corruption? > > > > Fred > > > > P.S. Since this happens only on cygwin, it > > might specific to any customizations to g++ > > for cygwin. All in all, cygwin's gcc is a much > > better indication of whether my code is buggy, > > because the solaris executables generally > > seem to run fine even when there are cringe- > > inducing bugs, which I only find because they > > crash on cygwin. > > Use "g++ -Wall". > Igor > -- > http://cs.nyu.edu/~pechtcha/ > |\ _,,,---,,_ [EMAIL PROTECTED] > ZZZzz /,`.-'`' -. ;-;;,_ [EMAIL PROTECTED] > |,4- ) )-,_. ,\ ( `'-' Igor Pechtchanski > '---''(_/--' `-'\_) fL a.k.a JaguaR-R-R-r-r-r-.-.-. Meow! > > Knowledge is an unending adventure at the edge of uncertainty. > -- Leto II > > > -- > Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple > Bug reporting: http://cygwin.com/bugs.html > Documentation: http://cygwin.com/docs.html > FAQ: http://cygwin.com/faq/ >
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