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Annoying. >>> > + */ >>> > +union pipe_index { >>> > + unsigned long head_tail; >>> > + struct { >>> > + pipe_index_t head; >>> > + pipe_index_t tail; >>> > + }; >>> > +}; >>> > + >>> >>> -fms-extensions ? Willy wanted to add that for use in mm/ some years ago >>> [*], and it has come up a few other times as well. >>> >>> [*] https://lore.kernel.org/lkml/20180419152817.GD25406@bombadil.infradead.org/ >> >> Oh, I was unaware of that extension, and yes, it would have been >> lovely here, avoiding that duplicate union declaration. >> >> But it does require clang support - I see that clang has a >> '-fms-extensions' as well, so it's presumably there. > > Yes, it seems they do have it, but for mysterious reasons saying > -fms-extensions is not quite enough to convince clang that one does > intend to use that MS extension, one also has to say > -Wno-microsoft-anon-tag, or it complains > > warning: anonymous unions are a Microsoft extension [-Wmicrosoft-anon-tag] > > Also, the warning text is somewhat misleading; anon unions itself have > certainly been a gcc extension since forever, and nowadays a C11 thing, > and clang has a separate -Wpedantic warning for that when using > -std=c99: > > warning: anonymous unions are a C11 extension [-Wc11-extensions] > > The -W flag name actually suggests an improvement to the warning > "_tagged_ anonymous unions are a Microsoft extension", but I really > wonder why -fms-extensions isn't sufficient to silence that in the first > place. Also, the warning seems to be on by default; it's not some > -Wextra or -Wpedantic thing. > > cc += Nick Gah, sorry, I wasn't aware that address didn't work anymore. So Cc -= everything but the lists and Cc += Nick for real this time, hopefully. Rasmus