[Bug c/108476] Please turn -Wreturn-type on by default for C
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108476
Xi Ruoyao changed:
What|Removed |Added
CC||xry111 at gcc dot gnu.org
--- Comment #5 from Xi Ruoyao ---
(In reply to Florian Weimer from comment #4)
> For GCC 14, we have -Wreturn-mismatch turned on by default, as an error.
> This diagnoses cases of extra or missing expressions in return statements.
> Together with the other warnings-as-errors changes, this seems to cover the
> request in the description.
It only catches
int f() { return; }
not a plain
int f() {}
AFAIK the standard (even the latest C23) still disallows us from simply
rejecting the latter.
[Bug c/108476] Please turn -Wreturn-type on by default for C
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108476 Florian Weimer changed: What|Removed |Added CC||fw at gcc dot gnu.org --- Comment #4 from Florian Weimer --- For GCC 14, we have -Wreturn-mismatch turned on by default, as an error. This diagnoses cases of extra or missing expressions in return statements. Together with the other warnings-as-errors changes, this seems to cover the request in the description.
[Bug c/108476] Please turn -Wreturn-type on by default for C
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108476 --- Comment #3 from Alex Henrie --- (In reply to Andrew Pinski from comment #1) > Note the warning should really be split into two different options. One for > the return type of the declaration and one for the missing return in > non-void case. That would be nice, I agree. I'd just like to note that since the warning should occur by default in both situations, this feature request does not depend on splitting the warning in two. (In reply to Jakub Jelinek from comment #2) > The reason it is enabled by default for C++ is that the 2 languages differ > significantly in this regard. Falling through the end of a non-void > function in C++ is undefined behavior, in C it is not, in C it is only UB if > the caller actually uses the uninitialized return value (which is much > harder to warn about). Yes, I did read the note about that in the documentation (although I didn't quote that part in comment #0). You're right that it's slightly less bad in C because not specifying the return value is immediately undefined behavior in C++, whereas in C it only becomes undefined behavior once the return value is used. However, few people know about that subtle difference between C and C++ (which leads to a false sense of security when the warning does not appear in C), and not specifying the return value will almost certainly lead to undefined behavior in C even though technically there are situations where it does not. > And in C it is enabled in -Wall, which you should use anyway if you care > about warnings. I do use -Wall whenever I can. Unfortunately, not everyone does (particularly novices or people stuck with awful embedded-toolchain IDEs that don't make it easy to change compiler settings), so I'd like the default to be both less confusing and more protective against likely undefined behavior.
[Bug c/108476] Please turn -Wreturn-type on by default for C
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108476 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org --- Comment #2 from Jakub Jelinek --- The reason it is enabled by default for C++ is that the 2 languages differ significantly in this regard. Falling through the end of a non-void function in C++ is undefined behavior, in C it is not, in C it is only UB if the caller actually uses the uninitialized return value (which is much harder to warn about). And in C it is enabled in -Wall, which you should use anyway if you care about warnings.
[Bug c/108476] Please turn -Wreturn-type on by default for C
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108476 Richard Biener changed: What|Removed |Added Keywords||diagnostic Severity|normal |enhancement
[Bug c/108476] Please turn -Wreturn-type on by default for C
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108476 Andrew Pinski changed: What|Removed |Added See Also||https://gcc.gnu.org/bugzill ||a/show_bug.cgi?id=53232 --- Comment #1 from Andrew Pinski --- Note the warning should really be split into two different options. One for the return type of the declaration and one for the missing return in non-void case.
