Failed to link opencv using g++ on LINUX

[indianscorpion]

Failed to link opencv using g++ on LINUX

Trying to link the library using g++ as below, it gave tons of errors. (cmake on examples works) -lnfiq2 -lFRFXLL_static -lopencv_core -lopencv_imgproc -lopencv_ml

errors: undefined reference to `cv::softdouble::operator*(cv::softdouble const&) const'

[gfiumara]

If the CMake in the example works, then the issue would be in your code, no? You are likely not linking all the OpenCV libraries you need for your project.

[indianscorpion]

I linked all the libraries in your release package as below, which one am I missing? -lnfiq2 -lFRFXLL_static -lopencv_core -lopencv_imgproc -lopencv_ml your lib64: libFRFXLL_static.a libnfiq2.a libnfir.a libopencv_imgproc.a libopencv_ml.a libopencv_core.a libNfiq2Api.so libFRFXLL.so

[gfiumara]

softdouble appears to be defined in core: https://docs.opencv.org/4.6.0/d7/dcc/group__core__utils__softfloat.html#gac2116f5bce2914d578953c6ac8c0da16

[indianscorpion]

it is using CV_EXPORTS softdouble cos( const softdouble& a ); should I include any link options?

[indianscorpion]

in /usr/local/nfiq2/include/opencv4/opencv2/core/softfloat.hpp

struct softfloat; struct softdouble;

struct CV_EXPORTS softfloat { public: /* @brief Default constructor / softfloat() { v = 0; }

struct CV_EXPORTS softdouble { public: /* @brief Default constructor / softdouble() : v(0) { } /* @brief Copy constructor / softdouble( const softdouble& c) { v = c.v; }

[gfiumara]

It's in opencv_core. You are likely not linking in an appropriate order. This is not an NFIQ 2 issue.

$ nm -C libopencv_core.a | grep 'T cv::softdouble::operator\*'
0000000000000000 T cv::softdouble::operator*(cv::softdouble const&) const

[indianscorpion]

yes, the correct linking order is as below: -lnfiq2 -lFRFXLL_static -lopencv_ml -lopencv_imgproc -lopencv_core