I've got a problem with include in a qmake project. In my .pro file I've got:
INCLUDEPATH += "C:\OpenCV\build\include"
and in my cpp :
#include <opencv\cv.h>
The compiler indicates an error:
Cannot open include file: 'opencv\cv.h': No such file or directory
but if I write this in my cpp:
#include "C:\OpenCV\build\include\opencv\cv.h"
it works!
I build the project from within Qt Creator. What am I doing wrong?
You have to run qmake(build->run qmake) to validate changes in the pro file.
Qt creator Adding external library (still: Cannot open include file: 'GL/glew.h')
Your problem may be related to the fact that having backslashes in naked #include directives is undefined behavior.
Do the following.
Replace your include with
#include <opencv/cv.h>
Note the forward slash!
Remove the shadow build directory that Qt Creator has made for you. You will find it above the project directory, its name begins with build-.
Rebuild the project.
Note that this takes care of rerunning qmake.
here's one of my pro files:
# Blah Application
TEMPLATE = app
CONFIG += qt console staticlib debug_and_release
QT -= gui
QT += network sql xml
TARGET = blah
CONFIG(debug, debug|release){
DESTDIR = debug
LIBS += -L../../../lib/core/debug -lcore
} else {
DESTDIR = release
LIBS += -L../../../lib/core/release -lcore
}
DEPENDPATH += . ../../lib ../../../lib/core
INCLUDEPATH += . ../../lib ../../../lib/core
# Library files
HEADERS += mtBlahRTP.h
SOURCES += mtBlahRTP.cpp
# Input
HEADERS +=
SOURCES += main.cpp
The include path points to the RELATIVE directory of my lib files. mtBlahRTP.h and mtBlahRTP.cpp are in ../../lib
I have the same question, before building or running, you should qmake(Build=>qmake) it.
My configurations for INCLUDEPATH:
INCLUDEPATH+=D:\opencv\opencv\build\include
INCLUDEPATH+=D:\opencv\opencv\build\include\opencv
INCLUDEPATH+=D:\opencv\opencv\build\include\opencv2
I ran into a similar issue and what I found is that the QtCreator IDE is not re-reading the results of qmake and updating the "Cannot open" message. You need to close the offending file and re-open it - then you'll see that it no longer displays the error.
I had to do two steps: (re-)run qmake and rebuild the whole project - only then the INCLUDEPATH setting was considered correctly. (With QtCreator 3.5 and 3.6 (Qt 5.5 and Qt 5.6) on Windows.)
The only problem you are making is incorrectly linking the OpenCV library. The other answers given here may or may not work, but I have posted on another thread a surefire way to solve this problem using the "Add Library" wizard inside Qt Creator: https://stackoverflow.com/a/51914928/10245006
I was getting the error:
canserialcomm.o: In function `CanSerialComm::CanSerialComm()':
canserialcomm.cpp:(.text+0xc1): undefined reference to `vtable for CanSerialComm'
It turns out that the cause was it wasn't able to find canserialcomm.h where that constructor is declared. This was despite me having INCLUDEPATH in the project file point to the directory containing that header file:
INCLUDEPATH += . \
..
What I had to do to fix this is explicitely specify the header file; I added:
HEADER += ../canserialcomm.h
You should use double backslashes when in windows for qt creator with msvc. like this:
INCLUDEPATH += C:\\libcurl\\libcurl-vc-x64-release-dll-ipv6-sspi-winssl\\include
this will fix the problem.
Under windows you have to eliminate the -I before each directory that is added into the INCLUDEPATH variable.
For example:
Under windows:
INCLUDEPATH += "C:\lib\boost_1_61_0" (back-slash)
Under linux & mac:
INCLUDEPATH += -I"$$(HOME)/lib/boost_1_61_0" (note the -I and forward-slash)
I'm not sure whether it depends on different qmake version or not. But after finishing qmake command, I check the Makefile and the double -I is the issue.
You need to do several things. Fist, in the .pro file, you need quotation marks two backslashes at a time, like this:
INCLUDEPATH += "C:\\OpenCV\\build\\include\\opencv\\cv.h"
You alse need a frontslash in the #include in your .cpp file like this:
#include <opencv/cv.h>
When you've done this, delete the build folder. This is the folder with a very complicated name of the type build-untitled-Desktop_Qt_5_7_0_MSVC2015_32bit-Release. Then, in the Build menu, press "Run qmake". When you've done all this, it should compile fine.
Somehow it did not work for when I had several INCLUDEPATH +=.
When I combined the stuff into a single on it suddenly worked.
I am using QT Creator 2.4.1. I want to make a network utility. I am using windows function:
GetAdaptersInfo().
This requires iphlpapi.lib to be linked.
To link the libraries I tried to add following argument in Projects->Build-Setup->Additional Arguments :
LIBS += -liphlpapi
or
win32:LIBS += -liphlpapi
or
LIBS += iphlpapi.lib
Without any success. I tried to give full path too. Can anyone tell me whats the correct way of linking?
This works:
Add win32:LIBS += -lIphlpapi in your .pro file;
clean (optional?);
run qmake;
build.
I wrote a small app with qt and opengl (code) and I want to compile it static now.
So i downloaded Qt library and compile it static using this guide.
I added a line CONFIG += static to the pro file cd to the project location and hit:
make clean
qmake -config release
make
but I am getting several undefined references like:
qpixmapdata_gl.cpp:-1: error: undefined reference to `_imp___Z14qt_defaultDpiYv'
What I am doing wrong? Do I need to add the libs to the pro file? How do I do this and more important what libs should I use?
I tried something like this with no result:
LIBS += C:\Qt\4.7.3\bin\QtOpenGL4.dll
I see that symbol is defined in qfont.cpp, so it should be there. I would try to add:
QT += gui
in your .pro file. And I suppose you need:
QT += core
also.
EDIT: Try also to check that the symbol is included in the libQtGui.lib and the line used to compile.
Are you using the same compiler also? The mangling reported seems that of gcc. Did you compile Qt libraries with mingw or nmake?
I've got a problem with my project. I am developing it on Qt Creator, and I need to add a .lib file to my project. So, I wrote this line in my .pro :
LIBS += "C:\My_Path\My_Project\lib\file.lib"
This is working fine. My only issue is that I need to write the entire path to the .lib file. Since it's a group project, it needs to be compilable on other computers without changing the path to this file every times.
I tried many syntaxes, like :
LIBS += -L"lib/" -l"file.lib"
or
LIBS += "lib\file.lib"
or
LIBS += "file.lib"
(putting the .lib file at the root and adding it to the project in Qt Creator)
None of them works :/
I also tried to add the .lib file in a QResource file but a syntax like this one :
LIBS += ":/lib/file.lib"
in a .pro file doesn't seem to work...
I am now running out of ideas :(
Help please :)
Did you try
LIBS += -Llib -lfile
or
LIBS += -L./lib -lfile?
Remember if you aren't using the full path, you don't add .lib to the library name and you don't use quotes. If the path has spaces (or you just want to be safe), use $$quote(-L<path name>)
As stated here the Unix style paths work on Windows as well where you normally need to provide the full path. qmake will fill it in for you.
I converted
LIBS += ../../lib/phraseBox.lib
to
LIBS += $$quote(-L../../lib) -lphraseBox
and
LIBS += $$quote(-L../../lib) phraseBox.lib
In one of my project with no problem on Windows. You might want to post your project files somewhere, or post the actual error messages to narrow this down.
Ok, I found the solution :
the lib/ directory has to be placed in the same directory that the Makefile (the real one, not the .pro).
Since I copied the lib/ directory in the build-desktop/ directory, everything is working fine using relative paths :)
From your tries I guess you want to link to the library using relative path which should work just fine by default.
Try this:
LIBS += -L$$relative/directory/path -llibname
If it does not work, then you might want to try setting multiple INCLUDEPATH. :/
I want to use CTelephony API in Qt Symbian project but after including etel3rdparty.h and etel3rdparty.lib as library and header in .pro file like this:
LIBS += C:/NokiaQtSDK/Symbian/SDK/epoc32/release/armv5/lib/etel3rdparty.lib
INCLUDEPATH += C:/NokiaQtSDK/Symbian/SDK/epoc32/include
I am getting a lot of compilation errors.
Please share if someone faced and find the solution of this problem.
You are not supposed to include each library with the complete path in the .pro file. You need only the name of the lib, without the extension, prefixed with -l, i.e. in your case
LIBS += -letel3rdparty
Also, you would normally not need to add epoc32\include to the include path, as it's added by default.