https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44317
Kaz Kylheku <kkylheku at gmail dot com> changed:
What |Removed |Added
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CC| |kkylheku at gmail dot com
--- Comment #12 from Kaz Kylheku <kkylheku at gmail dot com> ---
(In reply to Harald van Dijk from comment #9)
> The comma should not be eaten, as the invocation of FAIL() is valid in
> standard C++. The rules of concatenation of empty pp-token sequences are
> well-defined: the empty sequences are replaced by placemarker preprocessor
> tokens, and concatenating any non-placeholder token with a placemarker
> preprocessor token produces the former, see [cpp.concat].
And thus, more directly to the point, here is the fix:
cpp -std=gnu++0x test.cpp
The behavior does not reproduce then; the comma eating works.
If you want GNU extensions, request the GNU dialect which most closely
corresponds to the ISO dialect you want.
The issue here is that ## __VA_ARGS__ is a conforming extension in C,
and so it can work even when an ISO dialect is selected.
The documentation does not mention that ## __VA_ARGS__ might be
valid in some dialects of C++ and so has to be enabled as a nonconforming
extension.
Also this is an opton. The following workaround also works for me,
on gcc 10.x on Debian 11:
#define ASSERT( cnd, ... ) SomeClass() __VA_OPT__(,) __VA_ARGS__
#define FAIL( ... ) SomeClass() __VA_OPT__(,) __VA_ARGS__
This works with "cpp" with no options, with "-std=gnu++0x",
and with "-std=c++0x".
This may be a better workaround for someone who doesn't want to broadly
switch to the GNU dialect. __VA_OPT__ didn't exist when this bug was opened.
