Re: -Werror=unused-but-set-variable

[Emmanuel Fleury <fleury%labri.fr@localhost>]

On 08/11/2011 04:31 PM, Julio Merino wrote:
> 
> Well, if the default was false we wouldn't have found these problems ;-) 

Right, painful but right. :)

>   And I doubt that anyone will do --enable-developer at all if the 
> default is false.

Well, when the developers are in 'cleaning code' mode, this option will
definitely be helpful...

> That said, I know that -Werror is problematic for end users.  An 
> alternative would be to only enable -Werror on HEAD and disable it in 
> all formal releases.  I am now thinking that disabling -Werror should be 
> separate from the use of all the other -W* flags though: i.e. always 
> show messages but only treat them as errors if we are running from HEAD.

Agreed.

> Aha.  Actually, this should have worked on your side because the code
> is currently using -Wall first and later -Wno-unused-parameters to
> silence this part of -Wall.  Might this be a bug in gcc 4.6?

Hmmm, I'm doubtful about it... I didn't heard about somebody "cleaning"
the option parser recently... Though I'm not following gcc-dev very
carefully, I admit.

> Could you paste a single gcc execution line from the build log to see
> in what order the -W flags are being passed to the compiler?

Here (after a 'make maintainer-clean && rm -f configure && autoreconf
-is && ./configure --enable-developer && make):

/bin/sh ./libtool  --tag=CC   --mode=compile gcc -DHAVE_CONFIG_H -I.
"-DATF_ARCH=\"unknown\"" "-DATF_BUILD_CC=\"gcc\""
"-DATF_BUILD_CFLAGS=\"-g -O2  -Werror  -g -Wall -Wcast-qual -Wextra
-Wno-unused-parameter -Wpointer-arith -Wredundant-decls -Wreturn-type
-Wshadow -Wsign-compare -Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2
-Wmissing-prototypes -Wno-traditional\"" "-DATF_BUILD_CPP=\"gcc -E\""
"-DATF_BUILD_CPPFLAGS=\"\"" "-DATF_BUILD_CXX=\"g++\""
"-DATF_BUILD_CXXFLAGS=\"-g -O2  -Werror  -g -Wall -Wcast-qual -Wextra
-Wno-unused-parameter -Wpointer-arith -Wredundant-decls -Wreturn-type
-Wshadow -Wsign-compare -Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2
-Wabi -Wctor-dtor-privacy -Wno-deprecated -Wno-non-template-friend
-Wno-pmf-conversions -Wnon-virtual-dtor -Woverloaded-virtual -Wreorder
-Wsign-promo -Wsynth\"" "-DATF_CONFDIR=\"/usr/local/etc/atf\""
"-DATF_INCLUDEDIR=\"/usr/local/include\""
"-DATF_LIBDIR=\"/usr/local/lib\""
"-DATF_LIBEXECDIR=\"/usr/local/libexec\"" "-DATF_MACHINE=\"i686\""
"-DATF_M4=\"\"" "-DATF_PKGDATADIR=\"/usr/local/share/atf\""
"-DATF_SHELL=\"/bin/bash\"" "-DATF_WORKDIR=\"/tmp\"" -I./atf-c   -g -O2
 -Werror  -g -Wall -Wcast-qual -Wextra -Wno-unused-parameter
-Wpointer-arith -Wredundant-decls -Wreturn-type -Wshadow -Wsign-compare
-Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2 -Wmissing-prototypes
-Wno-traditional -MT atf-c/libatf_c_la-build.lo -MD -MP -MF
atf-c/.deps/libatf_c_la-build.Tpo -c -o atf-c/libatf_c_la-build.lo `test
-f 'atf-c/build.c' || echo './'`atf-c/build.c
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -DATF_ARCH=\"unknown\"
-DATF_BUILD_CC=\"gcc\" "-DATF_BUILD_CFLAGS=\"-g -O2  -Werror  -g -Wall
-Wcast-qual -Wextra -Wno-unused-parameter -Wpointer-arith
-Wredundant-decls -Wreturn-type -Wshadow -Wsign-compare -Wswitch
-Wwrite-strings -D_FORTIFY_SOURCE=2 -Wmissing-prototypes
-Wno-traditional\"" "-DATF_BUILD_CPP=\"gcc -E\""
-DATF_BUILD_CPPFLAGS=\"\" -DATF_BUILD_CXX=\"g++\"
"-DATF_BUILD_CXXFLAGS=\"-g -O2  -Werror  -g -Wall -Wcast-qual -Wextra
-Wno-unused-parameter -Wpointer-arith -Wredundant-decls -Wreturn-type
-Wshadow -Wsign-compare -Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2
-Wabi -Wctor-dtor-privacy -Wno-deprecated -Wno-non-template-friend
-Wno-pmf-conversions -Wnon-virtual-dtor -Woverloaded-virtual -Wreorder
-Wsign-promo -Wsynth\"" -DATF_CONFDIR=\"/usr/local/etc/atf\"
-DATF_INCLUDEDIR=\"/usr/local/include\" -DATF_LIBDIR=\"/usr/local/lib\"
-DATF_LIBEXECDIR=\"/usr/local/libexec\" -DATF_MACHINE=\"i686\"
-DATF_M4=\"\" -DATF_PKGDATADIR=\"/usr/local/share/atf\"
-DATF_SHELL=\"/bin/bash\" -DATF_WORKDIR=\"/tmp\" -I./atf-c -g -O2
-Werror -g -Wall -Wcast-qual -Wextra -Wno-unused-parameter
-Wpointer-arith -Wredundant-decls -Wreturn-type -Wshadow -Wsign-compare
-Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2 -Wmissing-prototypes
-Wno-traditional -MT atf-c/libatf_c_la-build.lo -MD -MP -MF
atf-c/.deps/libatf_c_la-build.Tpo -c atf-c/build.c -o
atf-c/libatf_c_la-build.o
mv -f atf-c/.deps/libatf_c_la-build.Tpo atf-c/.deps/libatf_c_la-build.Plo

/bin/sh ./libtool  --tag=CC   --mode=compile gcc -DHAVE_CONFIG_H -I.
"-DATF_ARCH=\"unknown\"" "-DATF_BUILD_CC=\"gcc\""
"-DATF_BUILD_CFLAGS=\"-g -O2  -Werror  -g -Wall -Wcast-qual -Wextra
-Wno-unused-parameter -Wpointer-arith -Wredundant-decls -Wreturn-type
-Wshadow -Wsign-compare -Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2
-Wmissing-prototypes -Wno-traditional\"" "-DATF_BUILD_CPP=\"gcc -E\""
"-DATF_BUILD_CPPFLAGS=\"\"" "-DATF_BUILD_CXX=\"g++\""
"-DATF_BUILD_CXXFLAGS=\"-g -O2  -Werror  -g -Wall -Wcast-qual -Wextra
-Wno-unused-parameter -Wpointer-arith -Wredundant-decls -Wreturn-type
-Wshadow -Wsign-compare -Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2
-Wabi -Wctor-dtor-privacy -Wno-deprecated -Wno-non-template-friend
-Wno-pmf-conversions -Wnon-virtual-dtor -Woverloaded-virtual -Wreorder
-Wsign-promo -Wsynth\"" "-DATF_CONFDIR=\"/usr/local/etc/atf\""
"-DATF_INCLUDEDIR=\"/usr/local/include\""
"-DATF_LIBDIR=\"/usr/local/lib\""
"-DATF_LIBEXECDIR=\"/usr/local/libexec\"" "-DATF_MACHINE=\"i686\""
"-DATF_M4=\"\"" "-DATF_PKGDATADIR=\"/usr/local/share/atf\""
"-DATF_SHELL=\"/bin/bash\"" "-DATF_WORKDIR=\"/tmp\"" -I./atf-c   -g -O2
 -Werror  -g -Wall -Wcast-qual -Wextra -Wno-unused-parameter
-Wpointer-arith -Wredundant-decls -Wreturn-type -Wshadow -Wsign-compare
-Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2 -Wmissing-prototypes
-Wno-traditional -MT atf-c/libatf_c_la-check.lo -MD -MP -MF
atf-c/.deps/libatf_c_la-check.Tpo -c -o atf-c/libatf_c_la-check.lo `test
-f 'atf-c/check.c' || echo './'`atf-c/check.c
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -DATF_ARCH=\"unknown\"
-DATF_BUILD_CC=\"gcc\" "-DATF_BUILD_CFLAGS=\"-g -O2  -Werror  -g -Wall
-Wcast-qual -Wextra -Wno-unused-parameter -Wpointer-arith
-Wredundant-decls -Wreturn-type -Wshadow -Wsign-compare -Wswitch
-Wwrite-strings -D_FORTIFY_SOURCE=2 -Wmissing-prototypes
-Wno-traditional\"" "-DATF_BUILD_CPP=\"gcc -E\""
-DATF_BUILD_CPPFLAGS=\"\" -DATF_BUILD_CXX=\"g++\"
"-DATF_BUILD_CXXFLAGS=\"-g -O2  -Werror  -g -Wall -Wcast-qual -Wextra
-Wno-unused-parameter -Wpointer-arith -Wredundant-decls -Wreturn-type
-Wshadow -Wsign-compare -Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2
-Wabi -Wctor-dtor-privacy -Wno-deprecated -Wno-non-template-friend
-Wno-pmf-conversions -Wnon-virtual-dtor -Woverloaded-virtual -Wreorder
-Wsign-promo -Wsynth\"" -DATF_CONFDIR=\"/usr/local/etc/atf\"
-DATF_INCLUDEDIR=\"/usr/local/include\" -DATF_LIBDIR=\"/usr/local/lib\"
-DATF_LIBEXECDIR=\"/usr/local/libexec\" -DATF_MACHINE=\"i686\"
-DATF_M4=\"\" -DATF_PKGDATADIR=\"/usr/local/share/atf\"
-DATF_SHELL=\"/bin/bash\" -DATF_WORKDIR=\"/tmp\" -I./atf-c -g -O2
-Werror -g -Wall -Wcast-qual -Wextra -Wno-unused-parameter
-Wpointer-arith -Wredundant-decls -Wreturn-type -Wshadow -Wsign-compare
-Wswitch -Wwrite-strings -D_FORTIFY_SOURCE=2 -Wmissing-prototypes
-Wno-traditional -MT atf-c/libatf_c_la-check.lo -MD -MP -MF
atf-c/.deps/libatf_c_la-check.Tpo -c atf-c/check.c -o
atf-c/libatf_c_la-check.o

atf-c/check.c: In function 'atf_check_result_init':
atf-c/check.c:304:17: error: variable 'workdir' set but not used
[-Werror=unused-but-set-variable]
cc1: all warnings being treated as errors


Regards
-- 
Emmanuel Fleury

Maître de conférence,        | Bureau: 261
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