| Message ID | 1345123356-6673-1-git-send-email-ncopa@alpinelinux.org |
|---|---|
| State | New |
| Headers | show |
Natanael Copa <natanael.copa@gmail.com> wrote: > Fixes build against uClibc. > > uClibc provides 2 versions of clock_gettime(), one with realtime > support and one without (this is so you can avoid linking in -lrt > unless actually needed). This means that the clock_gettime() don't > need -lrt. We still need it for timer_create() so we check for this > function in addition. > > We also need check if -lm is needed for isnan(). > > Both -lm and -lrt are needed for libs_qga. > > Signed-off-by: Natanael Copa <ncopa@alpinelinux.org> Reviewed-by: Juan Quintela <quintela@redhat.com>
On 16 August 2012 14:22, Natanael Copa <natanael.copa@gmail.com> wrote: > Fixes build against uClibc. > > uClibc provides 2 versions of clock_gettime(), one with realtime > support and one without (this is so you can avoid linking in -lrt > unless actually needed). This means that the clock_gettime() don't > need -lrt. We still need it for timer_create() so we check for this > function in addition. > > We also need check if -lm is needed for isnan(). > > Both -lm and -lrt are needed for libs_qga. > > Signed-off-by: Natanael Copa <ncopa@alpinelinux.org> > --- > The Xen people have nagged me to get this patch upstream so I have come > up with a rebased v2 patch after consulting with pm215 on IRC. > > Please consider include this. > > Changes v1->v2: > - Check for sin() in addition to isnan() > - Add comment on why we also check for timer_create > - Use $LIBS and $libs_qga instead of $libm and $librt, based on > feedback from pm215 on IRC > - Do not remove the explicit add of -lm unless Haiku. This was due > to http://www.mail-archive.com/qemu-devel@nongnu.org/msg102965.html > I am not sure if this is valid, though. Certainly building a linux-user target works for me even without that explicit 'LIBS+=-lm' in Makefile.target. Blue, can you remember what you had in mind when you wrote that email? thanks -- PMM
On 16 August 2012 14:22, Natanael Copa <natanael.copa@gmail.com> wrote: > Fixes build against uClibc. > > uClibc provides 2 versions of clock_gettime(), one with realtime > support and one without (this is so you can avoid linking in -lrt > unless actually needed). This means that the clock_gettime() don't > need -lrt. We still need it for timer_create() so we check for this > function in addition. > > We also need check if -lm is needed for isnan(). > > Both -lm and -lrt are needed for libs_qga. This patch breaks building the linux-user targets with --static: cam-vm-266:precise:qemu$ ./configure --target-list=arm-linux-user --static Error: librt check failed The test program is failing to link with this /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/librt.a(timer_create.o): In function `timer_create': (.text+0x121): undefined reference to `pthread_once' and a lot of similar errors. (This seems to me like a glibc bug but since it's out there we rather have to deal with it I think.) -- PMM
On Mon, Aug 20, 2012 at 12:43 PM, Peter Maydell <peter.maydell@linaro.org> wrote: > On 16 August 2012 14:22, Natanael Copa <natanael.copa@gmail.com> wrote: >> Fixes build against uClibc. >> >> uClibc provides 2 versions of clock_gettime(), one with realtime >> support and one without (this is so you can avoid linking in -lrt >> unless actually needed). This means that the clock_gettime() don't >> need -lrt. We still need it for timer_create() so we check for this >> function in addition. >> >> We also need check if -lm is needed for isnan(). >> >> Both -lm and -lrt are needed for libs_qga. >> >> Signed-off-by: Natanael Copa <ncopa@alpinelinux.org> >> --- >> The Xen people have nagged me to get this patch upstream so I have come >> up with a rebased v2 patch after consulting with pm215 on IRC. >> >> Please consider include this. >> >> Changes v1->v2: >> - Check for sin() in addition to isnan() >> - Add comment on why we also check for timer_create >> - Use $LIBS and $libs_qga instead of $libm and $librt, based on >> feedback from pm215 on IRC >> - Do not remove the explicit add of -lm unless Haiku. This was due >> to http://www.mail-archive.com/qemu-devel@nongnu.org/msg102965.html >> I am not sure if this is valid, though. > > Certainly building a linux-user target works for me even without > that explicit 'LIBS+=-lm' in Makefile.target. Blue, can you remember > what you had in mind when you wrote that email? Build failed since math library functions (sin() etc.) were not found. > > thanks > -- PMM
On Mon, 20 Aug 2012 19:53:22 +0000 Blue Swirl <blauwirbel@gmail.com> wrote: > >> - Do not remove the explicit add of -lm unless Haiku. This was due > >> to > >> http://www.mail-archive.com/qemu-devel@nongnu.org/msg102965.html I > >> am not sure if this is valid, though. > > > > Certainly building a linux-user target works for me even without > > that explicit 'LIBS+=-lm' in Makefile.target. Blue, can you remember > > what you had in mind when you wrote that email? > > Build failed since math library functions (sin() etc.) were not found. The v2 and v3 patches I sent tests for sin() in addition to isnan (which normally is a macro). It might explain why it works now. Adding a second -lm does not hurt, but omitting it when needed breaks build on uclibc for sure, so it would be nice if the v3 patch could be applied. Thanks! -nc
On Tue, Aug 21, 2012 at 6:10 AM, Natanael Copa <ncopa@alpinelinux.org> wrote: > On Mon, 20 Aug 2012 19:53:22 +0000 > Blue Swirl <blauwirbel@gmail.com> wrote: > >> >> - Do not remove the explicit add of -lm unless Haiku. This was due >> >> to >> >> http://www.mail-archive.com/qemu-devel@nongnu.org/msg102965.html I >> >> am not sure if this is valid, though. >> > >> > Certainly building a linux-user target works for me even without >> > that explicit 'LIBS+=-lm' in Makefile.target. Blue, can you remember >> > what you had in mind when you wrote that email? >> >> Build failed since math library functions (sin() etc.) were not found. > > The v2 and v3 patches I sent tests for sin() in addition to isnan (which > normally is a macro). It might explain why it works now. > > Adding a second -lm does not hurt, but omitting it when needed breaks > build on uclibc for sure, so it would be nice if the v3 patch could be > applied. Now I get this on mingw32: config-host.mak is out-of-date, running configure Error: librt check failed > > Thanks! > > -nc
diff --git a/configure b/configure index edf9da4..a351f9b 100755 --- a/configure +++ b/configure @@ -2624,17 +2624,48 @@ fi ########################################## +# Do we need libm +cat > $TMPC << EOF +#include <math.h> +int main(void) { return isnan(sin(0.0)); } +EOF +if compile_prog "" "" ; then + : +elif compile_prog "" "-lm" ; then + LIBS="-lm $LIBS" + libs_qga="-lm $libs_qga" +else + echo + echo "Error: libm check failed" + echo + exit 1 +fi + +########################################## # Do we need librt +# uClibc provides 2 versions of clock_gettime(), one with realtime +# support and one without. This means that the clock_gettime() don't +# need -lrt. We still need it for timer_create() so we check for this +# function in addition. cat > $TMPC <<EOF #include <signal.h> #include <time.h> -int main(void) { return clock_gettime(CLOCK_REALTIME, NULL); } +int main(void) { + timer_create(CLOCK_REALTIME, NULL, NULL); + return clock_gettime(CLOCK_REALTIME, NULL); +} EOF if compile_prog "" "" ; then : elif compile_prog "" "-lrt" ; then LIBS="-lrt $LIBS" + libs_qga="-lrt $libs_qga" +else + echo + echo "Error: librt check failed" + echo + exit 1 fi if test "$darwin" != "yes" -a "$mingw32" != "yes" -a "$solaris" != yes -a \
Fixes build against uClibc. uClibc provides 2 versions of clock_gettime(), one with realtime support and one without (this is so you can avoid linking in -lrt unless actually needed). This means that the clock_gettime() don't need -lrt. We still need it for timer_create() so we check for this function in addition. We also need check if -lm is needed for isnan(). Both -lm and -lrt are needed for libs_qga. Signed-off-by: Natanael Copa <ncopa@alpinelinux.org> --- The Xen people have nagged me to get this patch upstream so I have come up with a rebased v2 patch after consulting with pm215 on IRC. Please consider include this. Changes v1->v2: - Check for sin() in addition to isnan() - Add comment on why we also check for timer_create - Use $LIBS and $libs_qga instead of $libm and $librt, based on feedback from pm215 on IRC - Do not remove the explicit add of -lm unless Haiku. This was due to http://www.mail-archive.com/qemu-devel@nongnu.org/msg102965.html I am not sure if this is valid, though. configure | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)