On Tue, May 24 2022, Junio C Hamano wrote: > Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes: > >> It doesn't mean that GCC has additionally proved that we'll later used >> it in a way that will have a meaningful impact on the behavior of our >> program, or even that it's tried to do that. See an excerpt from the GCC >> code (a comment) in [1]. > > But that means the warning just as irrelevant as "you stored 438 to > this integer variable". Sure, there may be cases where that integer > variable should not exceed 400 and if the compiler can tell us that, > that would be a valuable help to developers. But "you stored an > address of an object that can go out of scope in another object > whose lifetime lasts beyond the scope" alone is not, without "and > the caller that passed the latter object later dereferences that > address here". We certainly shouldn't -Werror on such a warning > and bend our code because of it. I think it says something that 1) we had exactly one of these in our codebase 2) as we've discussed the pointer isn't actually *needed* outside the scope of the function, it's just left-over. Now, if it were used, e.g. let's say we had some code that took the struct and inspected its members we'd likely have a segfault here, or worse it would "work", but only on the platforms we'd test at first. Which isn't the case with a leftover "int finished" holding a 438. The point of this warning, like so many others, is to ask "hey, do you really need to be running around with this particular pair of scissors?".
