Target "denseflow" links to target "Iconv::Iconv" but the target was not found.

[lakshaymehra]

Hi,

I installed OpenCV with CUDA from source and then cloned the denseflow repository to install denseflow as mentioned in the README:

cmake -DCMAKE_INSTALL_PREFIX=$HOME/app -DUSE_HDF5=no -DUSE_NVFLOW=no ..

However, I am getting the following CMake Error:

`-- The C compiler identification is GNU 7.5.0
-- The CXX compiler identification is GNU 7.5.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Performing Test COMPILER_SUPPORTS_CXX11
-- Performing Test COMPILER_SUPPORTS_CXX11 - Success
-- Performing Test COMPILER_SUPPORTS_CXX0X
-- Performing Test COMPILER_SUPPORTS_CXX0X - Success
-- Looking for pthread.h
-- Looking for pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE
-- Found CUDA: /usr/local/cuda (found version "11.0")
-- Found OpenCV: /usr/local (found version "4.5.3")
-- OpenCV library status:
-- config: /usr/local/lib/cmake/opencv4
-- version: 4.5.3
-- libraries: opencv_calib3d;opencv_core;opencv_dnn;opencv_features2d;opencv_flann;opencv_gapi;opencv_highgui;opencv_imgcodecs;opencv_imgproc;opencv_ml;opencv_objdetect;opencv_photo;opencv_stitching;opencv_video;opencv_videoio;opencv_aruco;opencv_barcode;opencv_bgsegm;opencv_bioinspired;opencv_ccalib;opencv_cudaarithm;opencv_cudabgsegm;opencv_cudacodec;opencv_cudafeatures2d;opencv_cudafilters;opencv_cudaimgproc;opencv_cudalegacy;opencv_cudaobjdetect;opencv_cudaoptflow;opencv_cudastereo;opencv_cudawarping;opencv_cudev;opencv_datasets;opencv_dnn_objdetect;opencv_dnn_superres;opencv_dpm;opencv_face;opencv_freetype;opencv_fuzzy;opencv_hdf;opencv_hfs;opencv_img_hash;opencv_intensity_transform;opencv_line_descriptor;opencv_mcc;opencv_optflow;opencv_phase_unwrapping;opencv_plot;opencv_quality;opencv_rapid;opencv_reg;opencv_rgbd;opencv_saliency;opencv_shape;opencv_stereo;opencv_structured_light;opencv_superres;opencv_surface_matching;opencv_text;opencv_tracking;opencv_videostab;opencv_wechat_qrcode;opencv_xfeatures2d;opencv_ximgproc;opencv_xobjdetect;opencv_xphoto
-- include path: /usr/local/include/opencv4
-- Boost found.
-- Found Boost components:
date_time;filesystem;iostreams
-- Boost library status:
-- version: 1.76.0
-- libraries: Boost::date_time;Boost::filesystem;Boost::iostreams
-- include path: /root/app/include
-- Configuring done
CMake Error at CMakeLists.txt:64 (add_executable):
Target "denseflow" links to target "Iconv::Iconv" but the target was not
found. Perhaps a find_package() call is missing for an IMPORTED target, or
an ALIAS target is missing?

CMake Error at CMakeLists.txt:35 (add_library):
Target "zzdenseflow" links to target "Iconv::Iconv" but the target was not
found. Perhaps a find_package() call is missing for an IMPORTED target, or
an ALIAS target is missing?

-- Generating done
-- Build files have been written to: /content/denseflow/build`

Can you please guide me through the solution for this?

Thanks,

Lakshay.

[Tortoise17]

I am also facing same problem.

[Maynafiesta]

I guess writer solved or ignored the problem long time ago, but for the ones who face the same problem, I solved the issue by just adding find_package( Iconv ) to CMakelists.txt file. If you using Makefile, you can easily find the way Makefile doing this on internet. I faced this problem because of different version on OpenCV( before 4.5.2 and now 4.7.0.) I hope this helps.

[GuaiGuaiOnMyComputer]

Thanks to @Maynafiesta , it worked. Simply adding a find_package(Iconv) fixed everything for me.
I faced this issue using opencv4.9, building the libraries into libopencv_world490.a. This problem had never occurred to me with opencv4.9 without building ```libopencv_world````, wonder how this occurred.