Need help installing opencv in termux. Who can help?

Question

Android

Followed this instruction - keep.01ue.com/?pi=785007&_a=app&_c=index&_m=p
At step 5, when I run make, an error occurs at 50%:

$ make                                  
 [  2%] Built target zlib               
   [  5%] Built target libjpeg-turbo     
    [  8%] Built target libtiff          
     [ 16%] Built target libwebp             
  [ 19%] Built target libjasper           
  [ 21%] Built target libpng             
   [ 26%] Built target IlmImf             
   [ 31%] Built target libprotobuf       
    [ 31%] Built target quirc              
   [ 35%] Built target carotene_objs      
   [ 35%] Built target tegra_hal            
 [ 36%] Built target ade                
   [ 36%] Built target opencv_videoio_plugins
[ 42%] Built target opencv_core           
[ 46%] Built target opencv_imgproc     
   [ 48%] Built target opencv_imgcodecs     
 [ 49%] Built target opencv_videoio      
  [ 49%] Built target opencv_highgui       
 [ 50%] Built target opencv_ts             
[ 50%] Linking CXX executable ../../bin/opencv_perf_core
/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_ts.a(ts_perf.cpp.o): in function `cv::operator<<(std::__ndk1::basic_ostream<char, std::__ndk1::char_traits<char> >&, cv::Mat const&)':                                    ts_perf.cpp:(.text._ZN2cvlsERNSt6__ndk113basic_ostreamIcNS0_11char_traitsIcEEEERKNS_3MatE+0xb8): undefined reference to `__atomic_fetch_add_4'                          /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ts_perf.cpp:(.text._ZN2cvlsERNSt6__ndk113basic_ostreamIcNS0_11char_traitsIcEEEERKNS_3MatE+0xdc): undefined reference to `__atomic_fetch_add_4'      /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ts_perf.cpp:(.text._ZN2cvlsERNSt6__ndk113basic_ostreamIcNS0_11char_traitsIcEEEERKNS_3MatE+0x198): undefined reference to `__atomic_fetch_add_4'     /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ts_perf.cpp:(.text._ZN2cvlsERNSt6__ndk113basic_ostreamIcNS0_11char_traitsIcEEEERKNS_3MatE+0x1d8): undefined reference to `__atomic_fetch_add_4'     /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_core.so.4.1.0: undefined reference to `__atomic_fetch_sub_8'
/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_core.so.4.1.0: undefined reference to `__atomic_load_4'                               /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_core.so.4.1.0: undefined reference to `__atomic_load_8'                               /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_core.so.4.1.0: undefined reference to `__atomic_store_4'                              /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_core.so.4.1.0: undefined reference to `__atomic_compare_exchange_8'                   /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_core.so.4.1.0: undefined reference to `__atomic_load_1'                               /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_core.so.4.1.0: undefined reference to `__atomic_store_1'                              /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: ../../lib/libopencv_core.so.4.1.0: undefined reference to `__atomic_fetch_add_8'
/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: /data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld generated: undefined reference to `__atomic_fetch_add_4'                               clang-8: error: linker command failed with exit code 1 (use -v to see invocation)   make[2]: *** [modules/core/CMakeFiles/opencv_perf_core.dir/build.make:542: bin/opencv_perf_core] Error 1                      make[1]: *** [CMakeFiles/Makefile2:1595: modules/core/CMakeFiles/opencv_perf_core.dir/all] Error 2                            
make: *** [Makefile:163: all] Error 2     
$

Tell me what to do? Has anyone experienced this =(

Answer 1

Judging by undefined reference to `__atomic_fetch_add_4'the processor used does not have the necessary atomic instructions and the compiler is trying to use the libatomic library. Try adding it to the flags:
LDFLAGS=" -llog -lpython3 -latomic" ...

Answer 2

Most likely, the error is in the action of the 5th step:
There should be 2 dots at the end (indicates the parent directory).
And first, of course, go to the build directory:
cd build