Compiler ignores my includes -I for new library version

Question

I think that this question is not specifically on OpenCV , it seems more an include problem, so please read it even if you don't know the library.

There is an old version of a library (OpenCV) that's installed in /usr/local on the remote machine where I'm working on and where I don't have sudo access.

I've installed an updated version in my local environment /home/spm1428/local and I'm compiling it by using -I/home/spm1428/local/include/opencv and -I/home/spm1428/local/include/opencv2 .

However, in a file where #include "opencv/opencv.hpp" I get this error:

In file included from /usr/local/include/opencv2/opencv.hpp:77:0,
                 from /home/spm1428/CloudCache/Utilities/Utility.hpp:11,
                 from ../Descriptors/Descriptor.cpp:17:
/usr/local/include/opencv2/highgui/highgui.hpp:165:25: error: redeclaration of ‘IMREAD_UNCHANGED’

It's an error given by the old version of the library installed in /usr/local , but I told him to use the local version using -I !

So it seems that the compiler ignores my -I directives and instead gives the priority to /usr/local/include

Why this happens?

If you wonder the whole compiling command is:

g++ -DCC_DISABLE_CUDA -I/home/spm1428/CloudCache -I/home/spm1428/local/include/opencv -I/home/spm1428/local/include/opencv2 -I/usr/include/boost -I/home/spm1428/vlfeat -O3 -g -Wall -c -fopenmp -std=c++11   -c -o Descriptor.o ../Descriptors/Descriptor.cpp

This error happens both using #include <opencv2/core.hpp> and include "opencv2/core.hpp" .

UPDATE OF NEW ERROR:

Changing: #incldue <opencv2/opencv.hpp> to #include "opencv2/core.hpp" #include "opencv2/imgproc/imgproc.hpp" solved the problem for some reason. However, now when I compile:

g++ -DCC_DISABLE_CUDA -I/home/spm1428/local/include -I/home/spm1428/CloudCache -I/home/spm1428/local/include/opencv -I/home/spm1428/local/include/opencv2 -I/usr/include/boost -I/home/spm1428/vlfeat -O3 -g -Wall -c -fopenmp -std=c++11   -c -o SIFTOpenCV.o ../Descriptors/SIFTOpenCV.cpp

I get this error:

../Descriptors/SIFTOpenCV.cpp:31:9: error: ‘class cv::Feature2D’ has no member named ‘detectAndCompute’
   sift->detectAndCompute(img, cv::Mat(), pts, descriptors);

SIFTOpenCV.cpp includes SIFTOpenCV.hpp , which includes #include "opencv2/xfeatures2d.hpp" . I think that this error is related somehow to the previous one.

The weirdest thing is that this compiles correctly on my local machine (where I have sudo access and I installed it /usr/local )

This is the class SIFTOpenCV.hpp :

#include "Descriptors/Descriptor.hpp"
#include <opencv2/xfeatures2d.hpp>

namespace cc{
    class SIFTOpenCV : public Descriptor{
    public:
        SIFTOpenCV(int nFeatures=0, int nOctaveLayers=3, double contrastThreshold=0.04, double edgeThreshold=10, double sigma=1.6);
        void mapParams(std::vector<std::pair<std::string,std::string>> &params);
        void ComputeDescriptors(cv::Mat &img, cv::Mat1f &descriptors);
    private:
        cv::Ptr<cv::xfeatures2d::SIFT> sift;
        int nFeatures, nOctaveLayers;
        double contrastThreshold, edgeThreshold, sigma;
    };
}

While Descriptor.hpp :

#include "opencv2/core.hpp"
#include <string>
#include <map>

namespace cc{
    class Descriptor{
    public:
        virtual void mapParams(std::vector<std::pair<std::string,std::string>> &params) = 0;
        virtual void ComputeDescriptors(cv::Mat &img, cv::Mat1f &descriptors) = 0;
        virtual void ComputeDescriptors(const std::string &fileName, const std::string &imgExt, cv::Mat1f &descriptor);
        virtual void ComputeDescriptors(const std::string &dirPath, const std::string &imgExt, std::vector<cv::Mat1f> &descriptors);
        void setResizeDim(const size_t resizeDim);
        void setSamples (const size_t samples);
        void setOMP(const bool omp);
        virtual ~Descriptor();
    private:
        void ComputeDescriptorsRange(const std::vector<std::string> &files, std::vector<cv::Mat1f> &descriptors, const int start, const int finish, size_t errors);
        size_t resizeDim = 0;   //comput full-size image
        int samples = 0;
        bool omp = true;
    };
}

Answer 1

I found the solution by myself: executing cpp -v returned me:

 /usr/local/include
 /usr/include
 /home/spm1428/local/include
 ...

This means that using -I/home/spm1428/local/include was ignored because already included, but the priority was given to the old version in /usr/local/include .

Installing OpenCV in a new local directory and include it with -I gave the priority to the new version and solved the problem.