I'm trying to add caffe to an existing project. I get 99 undefined reference errors, suggesting that it has something to do with linking libraries. The errors mention caffe, boost and google (relates to gflags or glog).
Linker command: (libcaffe is in /home/torcs/lib)
g++ main.o linuxspec.o -L/home/torcs/export/lib -lopenal -lalut -lvorbisfile -L/usr/lib -L/home/torcs/lib -lracescreens -lrobottools -lclient -lconfscreens -ltgf -ltgfclient -ltxml -lplibul -lraceengine -lmusicplayer -llearning -lplibjs -lplibssgaux -lplibssg -lplibsm -lplibsl -lplibsg -lplibul -lglut -lGLU -lGL -lpng -lz -ldl -lXrandr -lXrender -lXxf86vm -lXmu -lXi -lXt -lSM -lICE -lXext -lX11 -lm -lcaffe -lglog -o torcs-bin
Linker error (first 2 and final 2):
/home/torcs/export/lib/librobottools.so: undefined reference to `caffe::FillerParameter::_default_type_'
/home/torcs/export/lib/librobottools.so: undefined reference to `void caffe::caffe_gpu_set<float>(int, float, float*)'
...
/home/torcs/export/lib/librobottools.so: undefined reference to `caffe::NetStateRule::NetStateRule()'
/home/torcs/export/lib/librobottools.so: undefined reference to `caffe::Timer::MilliSeconds()'
collect2: error: ld returned 1 exit status
I added -lcaffe
and tried libcaffe.a
and libcaffe.so
separately but the number of errors is not decreasing as I add libraries. If I misspel -lcaff
it says cannot find libcaffe
, which it doesn't do otherwise, so the lib is included correctly I guess.
I read up on linker order (windows background) and found that the symbols only get added if they are on the required symbols list. More specific libs should be last, dependent libs should be first. I figured that if I only add lcaffe
at the end, the unrecognized symbol list should be populated, and at least the caffe symbols would be recognized, and maybe replaced by other dependencies. But that doesn't happen.
I tried to find whether libcaffe
supplies the references. For the final undefined reference (caffe::Timer::MilliSeconds()
), nm libcaffe.a
finds:
0000000000188090 T _ZN5caffe5Timer12MilliSecondsEv
0000000000187910 T _ZN5caffe8CPUTimer12MilliSecondsEv
Which suggest the reference is in the lib. But the undefined reference error doesn't go away.
I also tried adding boost libs and glog, didn't help.
Edit. There is some additional weird behaviour going on. I think it is unrelated, but am not sure. The first time I build after a make clean
I get an error about include <random>
:
/usr/include/c++/4.8/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support is currently experimental, and must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
This prevents the o
files and librobottools.so
from getting built. But if I make
again, the c++11 error disappears, this lib does get build, and I see the 99 undefined reference errors.