Future releases of GCC are planning to remove[0] default support for
some old features that were removed from C99 but GCC still accepts.
We can test for these changes by using the following -Werror=
directives
-Werror=implicit-int
-Werror=implicit-function-declaration
-Werror=int-conversion
-Werror=strict-prototypes
-Werror=old-style-definition
Doing so revealed an issue with the auto/ tests in that the test
programs always define main as
int main()
rather than
int main(void)
which results in a bunch of errors like
build/autotest.c:3:23: error: function declaration isn't a prototype [-Werror=strict-prototypes]
3 | int main() {
| ^~~~
build/autotest.c: In function 'main':
build/autotest.c:3:23: error: old-style function definition [-Werror=old-style-definition]
The fix was easy, it only required fixing the main prototype with
find -type f -exec sed -i 's/int main() {/int main(void) {/g' {} \;
Regardless of these upcoming GCC changes, this is probably a good thing
to do anyway for correctness.
[0]: https://fedoraproject.org/wiki/Changes/PortingToModernC
Link: <https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/CJXKTLXJUPZ4F2C2VQOTNMEA5JAUPMBD/>
Link: <https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/6SGHPHPAXKCVJ6PUZ57WVDQ5TDBVIRMF/>
Reviewed-by: Alejandro Colomar <alx@nginx.com>
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>