Re: [PATCH] tests/ programs need -lrt too since they use clock_gettime.

["Török Edwin" <edwintorok@gmail.com>]

On 04/09/2010 10:00 PM, Julien Cristau wrote:
> On Fri, Apr  9, 2010 at 16:46:46 +0300, Török Edwin wrote:
>
>> When using the binutils gold linker, even if libdrm.so is already linked against
>> -lrt you still need to link your app against -lrt if your app needs symbols from
>> it.
>>
>> Signed-off-by: Török Edwin<edwintorok@gmail.com>
>> ---
>>   tests/Makefile.am |    2 +-
>>   1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/tests/Makefile.am b/tests/Makefile.am
>> index 3e74705..81006ab 100644
>> --- a/tests/Makefile.am
>> +++ b/tests/Makefile.am
>> @@ -4,7 +4,7 @@ AM_CPPFLAGS = \
>>   	-I $(top_srcdir)/include/drm \
>>   	-I $(top_srcdir)
>>
>> -LDADD = $(top_builddir)/libdrm.la
>> +LDADD = $(top_builddir)/libdrm.la @CLOCK_LIB@
>>
>>   noinst_PROGRAMS = \
>>   	dristat \
>
> The tests don't use librt afaict, the uses of clock_gettime() are in
> libdrm and libdrm_intel.  So your explanation doesn't seem to make
> sense...

The test app links dristat.o, and that includes xf86drm.c that uses 
clock_gettime.

Here is the link error I get without my patch:
make[1]: Entering directory `/home/edwin/drm/tests
libtool: link: gcc -m32 -O2 -g -o .libs/dristat dristat.o 
../.libs/libdrm.so
/usr/bin/ld: dristat.o: in function drmWaitVBlank:../xf86drm.c:1930: 
error: undefined reference to 'clock_gettime'
/usr/bin/ld: dristat.o: in function drmWaitVBlank:../xf86drm.c:1941: 
error: undefined reference to 'clock_gettime'
collect2: ld returned 1 exit status

dristat.c is including xf86drm.c directly (no idea why, shouldn't it get 
what it needs from libdrm.so?):
#include "xf86drm.c"

And xf86drm.c uses clock_gettime:
xf86drm.c:    ret = clock_gettime(CLOCK_MONOTONIC, &timeout);
xf86drm.c:      fprintf(stderr, "clock_gettime failed: %s\n", 
strerror(ret));
xf86drm.c:             clock_gettime(CLOCK_MONOTONIC, &cur);


Best regards,
--Edwin

------------------------------------------------------------------------------
Download Intel&#174; Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
--