http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57166
Bug #: 57166
Summary: Manual no longer documents -Wmissing-noreturn alias
for -Wsuggest-attribute=noreturn
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: j...@joshtriplett.org
Older versions of GCC had an option -Wmissing-noreturn, which acts like
-Wsuggest-attribute=noreturn does now. Current versions of GCC seem to accept
that option as an alias for -Wsuggest-attribute=noreturn, to the point where
the warnings generated by -Wmissing-noreturn get attributed to
-Wsuggest-attribute=noreturn:
error: function might be candidate for attribute 'noreturn'
[-Werror=suggest-attribute=noreturn]
However, if the compiler command line has -Wmissing-noreturn on it,
-Wno-suggest-attribute=noreturn will not turn it back off; only
-Wno-missing-noreturn will do that. The same applies in reverse. Test case:
$ cat test.c
void f(void)
{
while (1)
;
}
int main(void)
{
f();
return 0;
}
$ gcc -Wall -Wsuggest-attribute=noreturn -Wno-suggest-attribute=noreturn test.c
-o /dev/null
$ gcc -Wall -Wmissing-noreturn -Wno-suggest-attribute=noreturn test.c -o
/dev/null
test.c: In function ‘f’:
test.c:1:6: warning: function might be candidate for attribute ‘noreturn’
[-Wsuggest-attribute=noreturn]
$ gcc -Wall -Wmissing-noreturn -Wno-missing-noreturn test.c -o /dev/null
$ gcc -Wall -Wsuggest-attribute=noreturn -Wno-missing-noreturn test.c -o
/dev/null
test.c: In function ‘f’:
test.c:1:6: warning: function might be candidate for attribute ‘noreturn’
[-Wsuggest-attribute=noreturn]
The GCC manual should continue to document the alias -Wmissing-noreturn as long
as it continues to work (just as it currently documents
-Wmissing-format-attribute in addition to -Wsuggest-attribute=format).
In addition, I'd suggest that the -Wno-* forms of either option should cancel
out the other, since otherwise looking at the warning attribution supplied by
GCC and adding the corresponding -Wno-* for that option will not turn off the
warning.
