[ovs-dev] [PATCH] INSTALL: Describe how to use a separate build directory.

YAMAMOTO Takashi yamamoto at valinux.co.jp
Wed May 14 19:13:55 UTC 2014

> On Tue, May 13, 2014 at 10:36:30AM +0900, YAMAMOTO Takashi wrote:
>> > On Sat, May 10, 2014 at 08:17:16AM -0700, Ben Pfaff wrote:
>> >> On Sat, May 10, 2014 at 02:17:26PM +0900, YAMAMOTO Takashi wrote:
>> >> > btw, --enable-Werror CC=clang doesn't work.
>> >> > (clang complains about -g for linking)
>> >> > is it only for me?  a workaround is LDFLAGS=-Qunused-argument.
>> > 
>> > Thinking about it a bit further, I am a little surprised that we are
>> > passing -Werror as part of flags for linking.  I think that we only add
>> > -Werror to CFLAGS, so it should not appear when linking.  Are we doing
>> > something wrong there?
>> my undestanding is:
>> - AC_PROG_CC considers clang as gcc and sets CFLAGS=-g -O2.
>> - --enable-Werror ends up to add -Werror to CFLAGS.
>>   (thus CFLAGS=-g -O2 -Werror)
>> - automake generates the following for linking on my environment.
>>     LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
>>             $(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
>>             $(AM_LDFLAGS) $(LDFLAGS) -o $@
>> - clang complains "clang: error: argument unused during compilation: '-g'"
> OK.  I see you're right.  So every project that uses Autoconf and
> Automake generates such a warning (or error, with -Werror), with every
> link step, on your system when building with clang?  I do not see one

while i haven't tried other autoconf/automake using programs,
google'ing told me that it isn't so rare symptom.

> here.  I wonder what is different about your clang and mine.

no idea.

kuma% clang --version
clang version 3.4 (tags/RELEASE_34/final)
Target: x86_64--netbsd
Thread model: posix
kuma% clang -'###' -g a.o
clang version 3.4 (tags/RELEASE_34/final)
Target: x86_64--netbsd
Thread model: posix
clang: warning: argument unused during compilation: '-g'
 "/usr/bin/ld" "--eh-frame-hdr" "-dynamic-linker" "/libexec/ld.elf_so" "-o" "a.out" "/usr/lib/crt0.o" "/usr/lib/crti.o" "/usr/lib/crtbegin.o" "a.o" "-lc" "/usr/lib/crtend.o" "/usr/lib/crtn.o"


More information about the dev mailing list