[Bug c/94389] __attribute__((warn_unused_result)) will warn if the result is discarded as an optimisation

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94389

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Compared to [[nodiscard]], warn_unused_result attempts to force users harder
not to ignore the return value.  So, it doesn't allow just (void) cast to shut
up the warning, and this foo () ? 0 : 0 or 0 * foo () is similar obfuscation to
ignore the result when whomever that added the warn_unused_result attribute
wanted users not to do that.
So, use [[nodiscard]] instead of you want less aggressive checking, or change
your code, like O_TEXT != 0 ? text_mode () ? O_TEXT : 0 : 0 where you wouldn't
even call the function if you want to ignore the return value.