x86_64-unknown-linux-gnu/bin/ld: cannot find -lpthreads
I'm installing opencv 3.3 with centOS 6.9, gcc 4.8.5, cmake 3.11.1 ,cuda 9.0 and cudnn 7.0. I have been stuck on this question for quite a while. cmake error output as below.
CMakeFiles/cmTC_09750.dir/CheckSymbolExists.c.o: In function `main':
**CheckSymbolExists.c:(.text.startup+0x3): undefined reference to `pthread_create'**
collect2: error: ld returned 1 exit status
gmake[1]: *** [cmTC_09750] Error 1
gmake[1]: Leaving directory `/home/cch/Downloads/opencv/build/CMakeFiles/CMakeTmp'
gmake: *** [cmTC_09750/fast] Error 2
File /home/cch/Downloads/opencv/build/CMakeFiles/CMakeTmp/CheckSymbolExists.c:
/* */
#include <pthread.h>
int main(int argc, char** argv)
{
(void)argv;
#ifndef pthread_create
return ((int*)(&pthread_create))[argc];
#else
(void)argc;
return 0;
#endif
}
Determining if the function pthread_create exists in the pthreads failed with the following output:
Change Dir: /home/cch/Downloads/opencv/build/CMakeFiles/CMakeTmp
Run Build Command:"/usr/bin/gmake" "cmTC_c092d/fast"
/usr/bin/gmake -f CMakeFiles/cmTC_c092d.dir/build.make CMakeFiles/cmTC_c092d.dir/build
gmake[1]: Entering directory `/home/cch/Downloads/opencv/build/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_c092d.dir/CheckFunctionExists.c.o
/usr/bin/cc -fPIC -DCHECK_FUNCTION_EXISTS=pthread_create -O3 -DNDEBUG -o CMakeFiles/cmTC_c092d.dir/CheckFunctionExists.c.o -c /usr/local/cmake-3.11.1/share/cmake-3.11/Modules/CheckFunctionExists.c
Linking C executable cmTC_c092d
/usr/local/cmake-3.11.1/bin/cmake -E cmake_link_script CMakeFiles/cmTC_c092d.dir/link.txt --verbose=1
/usr/bin/cc -fPIC -DCHECK_FUNCTION_EXISTS=pthread_create -O3 -DNDEBUG -rdynamic CMakeFiles/cmTC_c092d.dir/CheckFunctionExists.c.o -o cmTC_c092d -lpthreads
**/usr/lib/gcc/x86_64-unknown-linux-gnu/4.8.5/../../../../x86_64-unknown-linux-gnu/bin/ld: cannot find -lpthreads**
collect2: error: ld returned 1 exit status
gmake[1]: *** [cmTC_c092d] Error 1
gmake[1]: Leaving directory `/home/cch/Downloads/opencv/build/CMakeFiles/CMakeTmp'
gmake: *** [cmTC_c092d/fast] Error 2
> [root@IB1 include]# ldconfig -v | grep
> pthread ldconfig:
> /etc/ld.so.conf.d/kernel-2.6.32-696.el6.x86_64.conf:6:
> duplicate hwcap 1 nosegneg ldconfig:
> Path `/lib64' given more than once
> ldconfig: Can't stat /libx32: No such
> file or directory ldconfig: Can't stat
> /usr/libx32: No such file or directory
> libpthread.so.0 -> libpthread-2.17.so
> libpthread.so.0 -> libpthread-2.12.so
> ldconfig: Cannot stat
> /usr/lib64/libGL.so: No such file or
> directory libgpgme-pthread.so.11 ->
> libgpgme-pthread.so.11.6.6
> libpthread.so.0 -> libpthread-2.12.so
I wonder what I should do next?
Seems like someone somewhere is using the library name pthreads instead of pthread. The correct library to link with is -lpthread, not -lpthreads.
Nobody is. Cmake tries -lpthreads internally, then -lpthread, then goes off and does something else, which fails silently.