Re: [libvirt] [PATCH] build: work around gcc 6.0 warnings

On Wed, Feb 24, 2016 at 02:29:58PM -0700, Eric Blake wrote: > gcc 6.0 added an annoying warning: > > fdstream.c: In function 'virFDStreamWrite': > fdstream.c:390:29: error: logical 'or' of equal expressions [-Werror=logical-op] > if (errno == EAGAIN || errno == EWOULDBLOCK) { > ^~ > fdstream.c: In function 'virFDStreamRead': > fdstream.c:440:29: error: logical 'or' of equal expressions [-Werror=logical-op] > if (errno == EAGAIN || errno == EWOULDBLOCK) { > ^~ > > This makes it impossible to build out-of-the-box on rawhide, > and we aren't guaranteed that the gcc bug will be fixed in a > timely manner: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69602 > > So work around it by further complicating the logic to thwart the > compiler. Personally I don't like this approach. Why don't we take that 6 line reproducer from GCC BZ and create a m4 macro that will detect that bug in GCC and turn off the logical-op check? For me this solution is much cleaner than introducing some ugly workaround in our code just because GCC has a bug.