<div dir="ltr"><div dir="ltr"><div dir="ltr"><div>autoconf seems to set GCC = yes for clang. I believe clang supports Wunused-variable instead of Wunused-but-set-variable. We could use the former, which is also supported by gcc. For other unsupported options, we can work around with -Wno-unknown-warning-option or -Xclang-only=</div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Apr 2, 2019 at 8:02 AM Dan Williams <<a href="mailto:dcbw@redhat.com" target="_blank">dcbw@redhat.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Tue, 2019-04-02 at 15:34 +0200, Torsten Hilbrich wrote: > Hello, > > I tried to compile libmbim (1.16.0), libqmi (1.20.0) and ModemManager > (1.8.0) with clang and got strange results. > > I set the environment variables CC=clang and CXX=clang++ and ran the > autogen.sh, configure, and make steps. > > Then the configure noticed that clang was used and checked for the > supported warning options: > > CC='clang' > configure:3408: checking for gcc > configure:3435: result: clang > ... > configure:17644: checking whether gcc understands -Wno-unused-but- > set-variable > configure:17657: clang -c -Wall -std=gnu89 -g -O2 -Wmissing- > declarations -Wmissing-prototypes -Wdeclaration-after-statement > -Wstrict-prototypes -Wno-unused-parameter -Wno-sign-compare -Wno- > deprecated-declarations -Wno-unused-but-set-variable conftest.c >&5 > warning: unknown warning option '-Wno-unused-but-set-variable'; did > you mean '-Wno-unused-const-variable'? [-Wunknown-warning-option] > 1 warning generated. > configure:17657: $? = 0 > configure:17666: result: yes I think -Wno-unused-but-set-variable is actually a mistake and it should be "-Wunused-but-set-variable". But that causes build errors that we should fix. Does clang support -Wunused-but-set-variable? Also, does making this change in m4/compiler_warnings.m4 of ModemManager sources help? - CFLAGS="$CFLAGS $option" + CFLAGS="$CFLAGS $option -Werror" Dan > > However, when compiling the code I got the following error messages: > > make[4]: Entering directory > '/build/client/clang/freedesktop/modemmanager/work/modemmanager/libqc > dm/src' > CC libqcdm_la-com.lo > error: unknown warning option '-Wno-unused-but-set-variable'; did you > mean '-Wno-unused-const-variable'? > [-Werror,-Wunknown-warning-option] > Makefile:516: recipe for target 'libqcdm_la-com.lo' failed > make[4]: *** [libqcdm_la-com.lo] Error 1 > > I assume that checking in configure is done without -Werror, but > compilation at least in libqdcdm is done with -Werror. > > > It this a known problem? Are fixes welcome to support compilation > with clang? > > The same problem happened in libmbim and libqmi. > > With regards, > > Torsten Hilbrich > > > _______________________________________________ > ModemManager-devel mailing list > <a href="mailto:ModemManager-devel@lists.freedesktop.org" target="_blank">ModemManager-devel@lists.freedesktop.org</a> > <a href="https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel</a> _______________________________________________ ModemManager-devel mailing list <a href="mailto:ModemManager-devel@lists.freedesktop.org" target="_blank">ModemManager-devel@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel</a></blockquote></div></div></div></div>