clEnqueueNDRangeKernel NULL event_wait_list

[rodrigonsh]

Hello! i'm trying to build on Freebsd12 and very early in the compilation I get this error

-- Build files have been written to: /root/Darknet-On-OpenCL/build
root@jarvis:~/Darknet-On-OpenCL/build # make
[  1%] Building CXX object CMakeFiles/darknet.dir/darknet_cl/src/activation_kernels_cl.cpp.o
/root/Darknet-On-OpenCL/darknet_cl/src/activation_kernels_cl.cpp:31:17: error: no matching function for call to 'clEnqueueNDRangeKernel'
        cl_int error = clEnqueueNDRangeKernel(*cl->queue, kernel, 3, NULL, global_size, NULL, NULL, NULL, &e);
                       ^~~~~~~~~~~~~~~~~~~~~~

/usr/local/include/CL/cl.h:1293:1: note: candidate function not viable: no known conversion from 'nullptr_t' to 'cl_uint' (aka 'unsigned int') for 7th argument
clEnqueueNDRangeKernel(cl_command_queue /* command_queue */,

Any idea?

[rodrigonsh]

Also, i'm ABSOLUTE BEGINNER , so mayble you could point me towards some docs and papers ?