On 09/06/2012 12:07 AM, Jim Meyering wrote: > Eric Blake wrote: > >> I compiled on FreeBSD 8.2 (gcc 4.2.1), and when I updated to the latest >> gnulib, I started to see the following in config.log when running >> ./configure CFLAGS=-g: >>
> When you configure with one set of warning options and later > build with another, as with your "make CFLAGS=-g", you're > short-circuiting the build tests. When I do that, I > simply turn off -Werror and ignore the warnings: > > make CFLAGS=-g WERROR_CFLAGS= But note that I did: ./configure CFLAGS=-g at the outset. Yes, I'm aware that _if_ you override CFLAGS at make time, you may have to also disable warnings at that time as well. But here, I'm talking about the case where I configured optimization to be off without needing to override CFLAGS at make time; that is, in a situation where we CAN run a configure test to see whether the warning will even be effective. > > Of course, you could simply rerun configure with CFLAGS=-g, Which is what I did... > and it would test each -W option individually... except that each -W option individually succeeds. -Wuninitialized only warns, not errors out, on this particular gcc 4.2.1 build. You _have_ to test the combination of '-Wuninitialized -Werror' but no -O, in order to hit the failure. But I'm not sure how best to modify manywarnings.m4 to do that testing. Then again, we've already special-cased -Wno-missing-field-initializer to work around gcc infelicities, so I guess I could enhance the module by adding another test along those lines. -- Eric Blake ebl...@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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