I have the same problem...

https://www.google.co.uk/search?q=undefined+reference+to+symbol+%27XInitThreads%27

Leads to:
http://stackoverflow.com/questions/23585435/cannot-call-xinitthreads

"undefined reference to symbol" is a linker error, not a compiler error. If you get this message, the compiler has already finished compiled the file into an object file, but is unable to find the shared library which contains the function to link the object file into an executable.

Using gcc, it generally means you have to add some -l flags, like so:

gcc prog.c -lX11

You can try adding it in the CMakesList.txt that references live_slam:
https://github.com/tum-vision/lsd_slam/blob/master/lsd_slam_core/CMakeLists.txt

Please explain in detail, where add libx11, but rather correct, please build rules because lsd-slam is not going on any configuration (ROS + Ubuntu)

on Ubuntu 14.04 helped reinstall libx11*

Hi,
could you try to compile commit
116c6c9
(just use 'git checkout 116c6c9')
and see if that works?
Jakob

another solution should be to add X11 to the library list:

target_link_libraries(lsdslam ${FABMAP_LIB} g2o_core g2o_stuff csparse cxsparse g2o_solver_csparse g2o_csparse_extension g2o_types_sim3 g2o_types_sba X11)

in line 89 of lsd_slam_core/CMakeLists.txt.
possibly you also have to install the respective ubuntu package, but I suppose it's already depended on somewhere. Just in case, run
sudo apt-get install libx11-dev

Please let me know if / what helped :)

Thanks Jakob. Your second solution worked.
i.e. Adding X11 to the line 89 of lsd_slam_core/CMakeLists.txt.

Thanks others for their replies as well.

Sorry for the late reply. I tried to uninstall X11 and reinstall, in the process I broke my Ubuntu installation :-). Hence reinstalled Ubuntu and everything else, got the above error again. Compilation was success after applying the fix by Jakob!

We could close the issue now!

another solution should be to add X11 to the library list:

target_link_libraries(lsdslam ${FABMAP_LIB} g2o_core g2o_stuff csparse cxsparse g2o_solver_csparse g2o_csparse_extension g2o_types_sim3 g2o_types_sba X11)

in line 89 of lsd_slam_core/CMakeLists.txt.
possibly you also have to install the respective ubuntu package, but I suppose it's already depended on somewhere. Just in case, run
sudo apt-get install libx11-dev

Please let me know if / what helped :)

Hi,

I have added X11 but still I am facing the same error.
I also want to know is there any difference between the following linking methods

1. -lX11
2. -L/usr/lib/X11