Incubator-mxnet: cv::imencode link error when building im2rec on Ubuntu 15.10

[nowozin]

Using Ubuntu 15.10 on x86_64 with libopencv-dev installed (Version: 2.4.9+dfsg-1ubuntu6) the following linker error results when compiling mxnet with OpenCV support. I copy make/config.mk to the main directory, enable OpenCV and compile with make, producing the output:

g++-4.9 -DMSHADOW_FORCE_STREAM -Wall -O3 -I./mshadow/ -I./dmlc-core/include -fPIC -Iinclude -msse3 -funroll-loops -Wno-unused-parameter -Wno-unknown-pragmas -I/usr/local/cuda/include -DMSHADOW_USE_CBLAS=1 -DMSHADOW_USE_MKL=0 -DMSHADOW_RABIT_PS=0 -DMSHADOW_DIST_PS=0 -DMXNET_USE_OPENCV=1 `pkg-config --cflags opencv` -fopenmp -march=native  -o bin/im2rec tools/im2rec.cc build/resource.o build/io/io.o build/io/iter_image_recordio.o build/io/iter_mnist.o build/common/tblob_op_registry.o build/common/mxrtc.o build/ndarray/unary_function.o build/ndarray/ndarray_function.o build/ndarray/ndarray.o build/operator/block_grad.o build/operator/leaky_relu.o build/operator/embedding.o build/operator/pooling.o build/operator/deconvolution.o build/operator/swapaxis.o build/operator/batch_norm.o build/operator/softmax_output.o build/operator/elementwise_sum.o build/operator/convolution.o build/operator/native_op.o build/operator/regression_output.o build/operator/slice_channel.o build/operator/concat.o build/operator/activation.o build/operator/elementwise_binary_op.o build/operator/ndarray_op.o build/operator/operator.o build/operator/lrn.o build/operator/dropout.o build/operator/cross_device_copy.o build/operator/elementwise_binary_scalar_op.o build/operator/fully_connected.o build/operator/reshape.o build/symbol/graph_executor.o build/symbol/static_graph.o build/symbol/symbol.o build/engine/naive_engine.o build/engine/threaded_engine_pooled.o build/engine/threaded_engine.o build/engine/engine.o build/engine/threaded_engine_perdevice.o build/storage/storage.o build/c_api/c_predict_api.o build/c_api/c_api.o build/c_api/c_api_error.o build/kvstore/kvstore.o dmlc-core/libdmlc.a build/ndarray/unary_function_gpu.o build/ndarray/ndarray_function_gpu.o build/operator/elementwise_binary_op_gpu.o build/operator/batch_norm_gpu.o build/operator/dropout_gpu.o build/operator/elementwise_binary_scalar_op_gpu.o build/operator/lrn_gpu.o build/operator/slice_channel_gpu.o build/operator/fully_connected_gpu.o build/operator/reshape_gpu.o build/operator/pooling_gpu.o build/operator/block_grad_gpu.o build/operator/leaky_relu_gpu.o build/operator/embedding_gpu.o build/operator/elementwise_sum_gpu.o build/operator/deconvolution_gpu.o build/operator/swapaxis_gpu.o build/operator/activation_gpu.o build/operator/softmax_output_gpu.o build/operator/concat_gpu.o build/operator/native_op_gpu.o build/operator/regression_output_gpu.o build/operator/convolution_gpu.o -pthread -lm -lcudart -lcublas -lcurand -L/usr/local/cuda/lib64 -L/usr/local/cuda/lib -lblas -lrt `pkg-config --libs opencv`  -lnvrtc -lcuda
/tmp/ccoTXSwt.o: In function `main':
im2rec.cc:(.text.startup+0x1c60): undefined reference to `cv::imencode(std::string const&, cv::_InputArray const&, std::vector<unsigned char, std::allocator<unsigned char> >&, std::vector<int, std::allocator<int> > const&)'
collect2: error: ld returned 1 exit status
Makefile:137: recipe for target 'bin/im2rec' failed
make: *** [bin/im2rec] Error 1

[piiswrong]

Could you run pkg-config --libs opencv and post your output?

[nowozin]

sn@hutu:~$ pkg-config --libs opencv
/usr/lib/x86_64-linux-gnu/libopencv_calib3d.so -lopencv_calib3d /usr/lib/x86_64-linux-gnu/libopencv_contrib.so -lopencv_contrib /usr/lib/x86_64-linux-gnu/libopencv_core.so -lopencv_core /usr/lib/x86_64-linux-gnu/libopencv_features2d.so -lopencv_features2d /usr/lib/x86_64-linux-gnu/libopencv_flann.so -lopencv_flann /usr/lib/x86_64-linux-gnu/libopencv_gpu.so -lopencv_gpu /usr/lib/x86_64-linux-gnu/libopencv_highgui.so -lopencv_highgui /usr/lib/x86_64-linux-gnu/libopencv_imgproc.so -lopencv_imgproc /usr/lib/x86_64-linux-gnu/libopencv_legacy.so -lopencv_legacy /usr/lib/x86_64-linux-gnu/libopencv_ml.so -lopencv_ml /usr/lib/x86_64-linux-gnu/libopencv_objdetect.so -lopencv_objdetect /usr/lib/x86_64-linux-gnu/libopencv_ocl.so -lopencv_ocl /usr/lib/x86_64-linux-gnu/libopencv_photo.so -lopencv_photo /usr/lib/x86_64-linux-gnu/libopencv_stitching.so -lopencv_stitching /usr/lib/x86_64-linux-gnu/libopencv_superres.so -lopencv_superres /usr/lib/x86_64-linux-gnu/libopencv_ts.so -lopencv_ts /usr/lib/x86_64-linux-gnu/libopencv_video.so -lopencv_video /usr/lib/x86_64-linux-gnu/libopencv_videostab.so -lopencv_videostab

And also

sn@hutu:~$ apt-cache show libopencv-dev
Package: libopencv-dev
Priority: optional
Section: universe/libdevel
Installed-Size: 653
Maintainer: Kubuntu Developers <[email protected]>
Original-Maintainer: Debian Science Team <[email protected]>
Architecture: amd64
Source: opencv
Version: 2.4.9+dfsg-1ubuntu6
Depends: libc6 (>= 2.14), libgcc1 (>= 1:4.1.1), libopencv-calib3d2.4v5, libopencv-core2.4v5, libopencv-highgui2.4v5, libopencv-imgproc2.4v5, libopencv-ml2.4v5, libopencv-objdetect2.4v5, libstdc++6 (>= 5.2), libopencv-core-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-ml-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-imgproc-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-video-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-objdetect-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-highgui-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-calib3d-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-flann-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-features2d-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-legacy-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-contrib-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-ts-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-photo-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-videostab-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-stitching-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-gpu-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-superres-dev (= 2.4.9+dfsg-1ubuntu6), libopencv-ocl-dev (= 2.4.9+dfsg-1ubuntu6), libopencv2.4-java (= 2.4.9+dfsg-1ubuntu6), libopencv2.4-jni (= 2.4.9+dfsg-1ubuntu6), libcv-dev (= 2.4.9+dfsg-1ubuntu6), libhighgui-dev (= 2.4.9+dfsg-1ubuntu6), libcvaux-dev (= 2.4.9+dfsg-1ubuntu6), pkg-config
Recommends: opencv-data
Breaks: libopencv-core-dev (<= 2.3.1-8)
Filename: pool/universe/o/opencv/libopencv-dev_2.4.9+dfsg-1ubuntu6_amd64.deb
Size: 167428
MD5sum: ecaf4191cf03536bff3e19cc1ddc424c
SHA1: d719e328151d771af7eaef054ee7edbbf803681d
SHA256: 0c7ec4a327a5c124ddcb6d5247a3e0a7421679a422aa005353830d59444d818e
Description-en: development files for opencv
 This is a metapackage providing development package necessary for
 development of OpenCV (Open Computer Vision).
 .
 The Open Computer Vision Library is a collection of algorithms and sample
 code for various computer vision problems. The library is compatible with
 IPL (Intel's Image Processing Library) and, if available, can use IPP
 (Intel's Integrated Performance Primitives) for better performance.
 .
 OpenCV provides low level portable data types and operators, and a set
 of high level functionalities for video acquisition, image processing and
 analysis, structural analysis, motion analysis and object tracking, object
 recognition, camera calibration and 3D reconstruction.
Description-md5: f9dc67381f1013c39fe59842c79cbddf
Homepage: http://opencv.org/
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu

[piiswrong]

I don't really know what happened, but maybe you can try adding the output of pkg-config --libs opencv to LDFLAGS in config.mk

[tqchen]

closing due to inactive state, please feel free to reopen

[dselivanov]

Also have problems when compiling with opencv on 15.10:

/tmp/ccU9s2mB.o: In function main': im2rec.cc:(.text.startup+0x1c37): undefined reference tocv::imencode(std::string const&, cv::_InputArray const&, std::vector >&, std::vector > const&)'
build/c_api/c_api.o: In function MXRecordIOReaderReadRecord': c_api.cc:(.text+0x23da): undefined reference todmlc::RecordIOReader::NextRecord(std::string_)'
collect2: error: ld returned 1 exit status
Makefile:137: recipe for target 'bin/im2rec' failed
make: *_* [bin/im2rec] Error 1

without opencv compiles fine

[Aelphy]

fixed the same problem using clang instead of gcc

[pppoe]

FYI, I ran into this issue and fixed it by recompiling OpenCV from source in C++0x.

[wangg12]

@Aelphy I also fixed the same problem using clang instead of gcc...