Re: [Qemu-devel] [PATCH] build: add needed missing libraries libm and librt

["Andreas Färber" <afaerber@suse.de>]

Am 18.02.2012 09:24, schrieb Blue Swirl:
> On Wed, Feb 8, 2012 at 17:06, Roger Pau Monne <roger.pau@entel.upc.edu> wrote:
>> libm is used in cutils.c, but the library was not specified
>> when linking some binaries, throwing the following error:
>>
>> cutils.o: In function `strtosz_suffix_unit':
>> /home/royger/xen-clean/tools/qemu-xen-dir/cutils.c:354: undefined
>> reference to `__isnan'
>> /home/royger/xen-clean/tools/qemu-xen-dir/cutils.c:357: undefined
>> reference to `modf'
>> collect2: ld returned 1 exit status
>>
>> According to modf man page [0], -lm should be used when linking.
>>
>> librt is used in qemu-time.c, but again the library was not specified
>> at link time, throwing the following error:
>>
>> /home/royger/xen-clean/tools/qemu-xen-dir/qemu-timer.c:597: undefined
>> reference to `timer_gettime'
>> /home/royger/xen-clean/tools/qemu-xen-dir/qemu-timer.c:610: undefined
>> reference to `timer_settime'
>> ../qemu-timer.o: In function `dynticks_start_timer':
>> /home/royger/xen-clean/tools/qemu-xen-dir/qemu-timer.c:565: undefined
>> reference to `timer_create'
>> ../qemu-timer.o: In function `dynticks_stop_timer':
>> /home/royger/xen-clean/tools/qemu-xen-dir/qemu-timer.c:583: undefined
>> reference to `timer_delete'
>> collect2: ld returned 1 exit status
>>
>> According to timer_getttime man page [1], -lrt should be used when
>> linking.
>>
>> [0] http://linux.die.net/man/3/modf
>> [1] http://linux.die.net/man/2/timer_gettime
> 
> This is Linux man page, is this correct for all OS we support?

No, not for Haiku or Mac OS X.

> We already have a test for -lrt in configure, but it looks like it
> does not detect your case correctly. You should fix that instead.
> 
>> Signed-off-by: Roger Pau Monne <roger.pau@entel.upc.edu>
>> ---
>>  Makefile        |    4 ++--
>>  Makefile.target |    2 ++
>>  2 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/Makefile b/Makefile
>> index 301c75e..e2c3cd4 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -34,7 +34,7 @@ configure: ;
>>
>>  $(call set-vpath, $(SRC_PATH):$(SRC_PATH)/hw)
>>
>> -LIBS+=-lz $(LIBS_TOOLS)
>> +LIBS+=-lz -lm -lrt $(LIBS_TOOLS)

NACK. You need to make sure it either lands in $(LIBS_TOOLS) or is added
via a new variable with host-dependent contents.

>>
>>  ifdef BUILD_DOCS
>>  DOCS=qemu-doc.html qemu-tech.html qemu.1 qemu-img.1 qemu-nbd.8 QMP/qmp-commands.txt
>> @@ -170,7 +170,7 @@ test-coroutine: test-coroutine.o qemu-timer-common.o async.o $(coroutine-obj-y)
>>  $(qapi-obj-y): $(GENERATED_HEADERS)
>>  qapi-dir := $(BUILD_DIR)/qapi-generated
>>  test-visitor.o test-qmp-commands.o qemu-ga$(EXESUF): QEMU_CFLAGS += -I $(qapi-dir)
>> -qemu-ga$(EXESUF): LIBS = $(LIBS_QGA)
>> +qemu-ga$(EXESUF): LIBS = $(LIBS_QGA) -lm

NACK. Either needs to do LIBS += or must go in $(LIBS_QGA) or new
conditionalized variable.

>>
>>  $(qapi-dir)/test-qapi-types.c $(qapi-dir)/test-qapi-types.h :\
>>  $(SRC_PATH)/qapi-schema-test.json $(SRC_PATH)/scripts/qapi-types.py
>> diff --git a/Makefile.target b/Makefile.target
>> index a111521..95d6bc0 100644
>> --- a/Makefile.target
>> +++ b/Makefile.target
>> @@ -33,6 +33,8 @@ endif
>>  PROGS=$(QEMU_PROG)
>>  STPFILES=
>>
>> +LIBS+=-lrt
>> +

>>  ifndef CONFIG_HAIKU
>>  LIBS+=-lm
>>  endif

Here's the special treatment that avoids adding -lm on Haiku host
because it doesn't have a libm.so (git-blame would've told you it's in
libroot.so there); on Darwin there's a compatibility symlink but it's in
libSystem.dylib actually and an ifndef would be appropriate as well.
POSIX does not mandate -lm for math functions.

Would moving this snippet to Makefile.objs help? What system are you on
anyway and are you actually using upstream qemu.git? openSUSE 12.1 does
not complain, and without a test case it's hard to find a solution here.

Andreas

>> --
>> 1.7.9

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg