使用pkg-config --cflgas opencv和pkg-config --ldflag但不能执行的程序正常运行(ubuntu 16.04)

Question

最近，我在我的ubuntu16.04机器上安装了opencv (我之前已经做过很多次了，使用它也没问题)。我试过编译yolo程序，它编译正常，运行正常。当我在Makefile中设置OPENCV=1时，它会用opencv编译程序。为了设置编译和链接标志，它有这两行。

LDFLAGS+= `pkg-config --libs opencv` -lstdc++
COMMON+= `pkg-config --cflags opencv`

我的pkg-config命令可以正常工作。请参见下面的输出。

ckim@chan-ubuntu:~/YOLOV2/darknet$ pkg-config --cflags opencv
-I/home/ckim/opencv_install/installation/OpenCV-3.4/include/opencv -I/home/ckim/opencv_install/installation/OpenCV-3.4/include
ckim@chan-ubuntu:~/YOLOV2/darknet$ pkg-config --libs opencv
-L/home/ckim/opencv_install/installation/OpenCV-3.4/lib -lopencv_stitching -lopencv_videostab -lopencv_superres -lopencv_surface_matching -lopencv_dnn_objdetect -lopencv_line_descriptor -lopencv_aruco -lopencv_img_hash -lopencv_xobjdetect -lopencv_dpm -lopencv_freetype -lopencv_stereo -lopencv_face -lopencv_objdetect -lopencv_structured_light -lopencv_phase_unwrapping -lopencv_saliency -lopencv_hfs -lopencv_ccalib -lopencv_tracking -lopencv_datasets -lopencv_plot -lopencv_optflow -lopencv_ximgproc -lopencv_fuzzy -lopencv_bioinspired -lopencv_highgui -lopencv_videoio -lopencv_text -lopencv_dnn -lopencv_reg -lopencv_hdf -lopencv_bgsegm -lopencv_rgbd -lopencv_sfm -lopencv_xfeatures2d -lopencv_calib3d -lopencv_shape -lopencv_imgcodecs -lopencv_features2d -lopencv_video -lopencv_ml -lopencv_flann -lopencv_xphoto -lopencv_photo -lopencv_imgproc -lopencv_core

几天前，我试着编译了一个简单的opencv程序，我在一个网页上找到了它，并试着编译它。(我想测试一个基本显示窗口的行为)。程序是这样的。非常典型)

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>

using namespace cv;
using namespace std;

int main( int argc, char** argv )
{
    if( argc != 2)
    {
     cout <<" Usage: display_image ImageToLoadAndDisplay" << endl;
     return -1;
    }

    Mat image;
    image = imread(argv[1], CV_LOAD_IMAGE_COLOR);   // Read the file

    if(! image.data )                              // Check for invalid input
    {
        cout <<  "Could not open or find the image" << std::endl ;
        return -1;
    }

    namedWindow( "Display window", WINDOW_AUTOSIZE );// Create a window for display.
    imshow( "Display window", image );                   // Show our image inside it.

    waitKey(1);                                          // Wait for a keystroke in the window
    return 0;
}

当我使用命令编译和链接它时

gcc -c test.cpp `pkg-config --cflags opencv` `pkg-config --libs opencv` -o test

它没有给我任何错误，我看到了test文件，但它不是可执行的。当我在设置chmod +x test之后运行它时，我得到

ckim@chan-ubuntu:~/opencvtest$ ./test
bash: ./test: cannot execute binary file: Exec format error
ckim@chan-ubuntu:~/opencvtest$ file test
test: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped

会出什么问题呢？

Answer 1

根据你的命令行..。

gcc -c test.cpp `pkg-config --cflags opencv` `pkg-config --libs opencv` -o test

包括-c标志，它告诉编译器只编译--不链接。还有。因为您的代码是c++而不是c，所以您需要链接到正确的运行时库。这意味着使用g++而不是gcc。所以命令应该是...

g++ test.cpp `pkg-config --cflags opencv` `pkg-config --libs opencv` -o test