File not found main.obj - c++

Question

I have QT installed in my PC, which is using the Visual Studio 2010 compiler
I tested this with a simple hello world application, and it works fine.
However now I am trying to use OpenCV with QT. I have installed Visual Studio 2010 express and professional both, and opencv works fine there. But, when I try to run the OpenCV in QT, I get the following error
main.obj:-1: error: LNK2019: unresolved external symbol "public: void __thiscall cv::Mat::deallocate(void)" (?deallocate#Mat#cv##QAEXXZ) referenced in function "public: void __thiscall cv::Mat::release(void)" (?release#Mat#cv##QAEXXZ)
main.obj:-1: error: LNK2019: unresolved external symbol "void __cdecl cv::fastFree(void *)" (?fastFree#cv##YAXPAX#Z) referenced in function "public: __thiscall cv::Mat::~Mat(void)" (??1Mat#cv##QAE#XZ)
main.obj:-1: error: LNK2019: unresolved external symbol "int __cdecl cv::waitKey(int)" (?waitKey#cv##YAHH#Z) referenced in function _main
main.obj:-1: error: LNK2019: unresolved external symbol "void __cdecl cv::imshow(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,class cv::_InputArray const &)" (?imshow#cv##YAXABV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##ABV_InputArray#1##Z) referenced in function _main
main.obj:-1: error: LNK2019: unresolved external symbol "public: __thiscall cv::_InputArray::_InputArray(class cv::Mat const &)" (??0_InputArray#cv##QAE#ABVMat#1##Z) referenced in function _main
main.obj:-1: error: LNK2019: unresolved external symbol "void __cdecl cv::namedWindow(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,int)" (?namedWindow#cv##YAXABV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##H#Z) referenced in function _main
main.obj:-1: error: LNK2019: unresolved external symbol "class cv::Mat __cdecl cv::imread(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,int)" (?imread#cv##YA?AVMat#1#ABV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##H#Z) referenced in function _main
release\FirstProject.exe:-1: error: LNK1120: 7 unresolved externals
Following is my FirstProject.pro file's content
#-------------------------------------------------
#
# Project created by QtCreator 2013-04-26T11:15:33
#
#-------------------------------------------------
QT += core
QT -= gui
TARGET = FirstProject
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
SOURCES += main.cpp
INCLUDEPATH += C:\opencv\build\include\
LIBS += -LC:\opencv\build\x86\vc10\lib \
-lopencv_calib3d240d.lib\
-lopencv_contrib240d.lib\
-lopencv_core240d.lib\
-lopencv_features2d240d.lib\
-lopencv_flann240d.lib\
-lopencv_gpu240d.lib\
-lopencv_haartraining_engined.lib\
-lopencv_highgui240d.lib\
-lopencv_imgproc240d.lib\
-lopencv_legacy240d.lib\
-lopencv_ml240d.lib\
-lopencv_nonfree240d.lib\
-lopencv_objdetect240d.lib\
-lopencv_photo240d.lib\
-lopencv_stitching240d.lib\
-lopencv_ts240d.lib\
-lopencv_video240d.lib\
-lopencv_videostab240d.lib
I tried by chainging to the following FirstProject.pro content, but no good at all
#-------------------------------------------------
#
# Project created by QtCreator 2013-04-26T11:15:33
#
#-------------------------------------------------
QT += core
QT -= gui
TARGET = FirstProject
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
SOURCES += main.cpp
INCLUDEPATH += C:\opencv\build\include\
LIBS += -LC:\opencv\build\x86\vc10\lib \
-lopencv_core240 \
-lopencv_highgui240 \
-lopencv_imgproc240 \
-lopencv_features2d240 \
-lopencv_calib3d240
Following is my code
main.cpp
#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
using namespace std;
using namespace cv;
int main()
{
Mat image = imread("D:/Tulips.jpg");
if(!image.data)
{
cout << "Error loading image" << endl;
}
else
{
namedWindow("Image");
imshow("Image",image);
}
waitKey(0);
return 0;
}
Why am I getting this error?

Answer 1

QT Project files try to handle file/directory separators uniformly, ie, forward v's back slashes. It shouldn't matter which is used. However, maybe there's some translation going on.
Try replacing all backslashes '\' with forward versions '/'. Qmake will convert them appropriately.
Replace with -LC:/opencv/build/x86/vc10/lib
It also might be the final backslash on your INCLUDEPATH that's the problem. Maybe it's joining up next line?

Answer 2

I found the answer. The only way to remove the issue is adding the libs one by one, with the complete path
LIBS += C:/opencv/build/x86/vc9/lib/opencv_calib3d240.lib
LIBS += C:/opencv/build/x86/vc9/lib/opencv_contrib240.lib

Answer 3

I had the same problem but I found the answer nowhere. after 8 days trying to fix it finally I found the answer and I want to share it with u.
when u use static linking opencv first check if your libraries are really static linked , to do so open a developer command prompt msvc , navigate into your libraries path , and type the command bellow :
lib /LIBS opencv_world.lib
rather than opencv_world.lib you can put any other library names.
then check there were only refrenced .obj files in it , so that means u can use this library static.
then remember when u use static lib in opencv , u need to at some other libraries to ur project that in dynamic linking u didnt need to. these libraries are in your library directory that their name doesnt start with opencv.
u can see some of them bellow :
IlmImf.lib
ippicvmt.lib
ippiw.lib
ittnotify.lib
libjasper.lib
libtiff.lib
libwebp.lib
zlib.lib
remeber , If u got the error "couldnt find library" , use the exact path to add it. for example :
LIBS += E:\opencv\build-x86-static\install\x86\vc15\staticlib\zlib.lib