Linking dll to c++ in qt for reading .mat files - qt

I am using Qt Creator 2.4.1(Based on Qt 4.7.4) ..
Now I want to open the .mat file which I got from Matlab.
I am using the basic function matOpen
Initially, I knew the headers required. They are mat.h, matrix.h and tmw.h.
Now, before running the code, I need to link the libraries. The required libraries as far as I know are libmat.dll and libmw.dll . I added them to the .pro file as follows.
QT += core
QT -= gui
TARGET = mat_open_test
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
SOURCES += main.cpp
HEADERS += \
mat.h \
matrix.h \
tmwtypes.h
LIBS += -L"C:\Users\skanduri\Documents\C ++\mat_open_test-build-desktop- Qt_4_8_1_for_Desktop_-_MinGW__Qt_SDK__Debug\debug\libmat.dll"
LIBS += -L"C:\Users\skanduri\Documents\C ++\mat_open_test-build-desktop-Qt_4_8_1_for_Desktop_-_MinGW__Qt_SDK__Debug\debug\libmx.dll"
Still I get error as : undefined reference to matOpen.. m sure the problem is with the linking.. But I dunno how to solve it. and the compiler Qt is using is MinGw .

You are specifying library path only, not the libraries itself. Try
LIBS += -L"C:\Users\skanduri\Documents\C ++\mat_open_test-build-desktop-Qt_4_8_1_for_Desktop_-_MinGW__Qt_SDK__Debug\debug"
LIBS += -llibmx
LIBS += -llibmat

Related

How to add opencv DLL on Windows to QTCreator project?

I've built opencv and added these lines to .pro file:
INCLUDEPATH += C:/opencv-3.4.1/build/install/include
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_core341d.lib
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_highgui341d.lib
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_imgcodecs341d.lib
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_imgproc341d.lib
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_features2d341d.lib
now if I start the project, it links successfully but fails to start:
Starting C:\Users\steve\Documents\build-qttest4-Desktop_Qt_5_11_0_MSVC2015_64bit-Debug\debug\qttest4.exe...
The program has unexpectedly finished.
The process was ended forcefully.
Can I somehow tell QTCreator to add DLL files to put opencv DLL files to build-qttest4-Desktop_Qt_5_11_0_MSVC2015_64bit-Debug folder?
Here is a solution (which doesn't match top google search tutorial):
INCLUDEPATH += C:/opencv-3.4.1/build/install/include
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_core341d.lib
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_highgui341d.lib
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_imgcodecs341d.lib
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_imgproc341d.lib
LIBS += C:\opencv-3.4.1\build\LIB\Debug\opencv_features2d341d.lib
LIBS += -L"C:/opencv-3.4.1/build/bin/Debug"
and don't forget to run Build->Run qmake.
There are 2 ways to use DLL in some Windows Application
Use WinAPI LoadLibrary function and GetProcAddress function.
Set inside a Qt PRO file a location of LIB file that will tell to application that binary code is in YourLibraryName.DLL. But when you run debugger, application doesn't know where is DLL. One of possible solutions is to put full path to opencv DLL folder to PATH environment variable in windows Control Panel

Run time error for a missing DLL which exists

I am writing a tool with Qt Creator which builds but immediately crashes with the message:
"The program can't start because pthreadVC2.dll is missing from your
computer. Try reinstalling the program to fix this problem".
Of course, the "pthreadVC2.dll" library is not missing (and is not corrupted, since it works with other projects), and it is located in the path specified in the Qt pro file:
# DeltaPlots.pro
TARGET = DeltaPlots
QT += core gui
CONFIG += console
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TEMPLATE = app
win32 {
INCLUDEPATH += S:\\3rdparty\\DFS.Infrastructure.ThreadingW \
S:\\3rdparty\\DFS.Infrastructure.File \
"C:\\path\\to\\boost\\boost_1_51_0"
win32-g++:LIBS += -L"S:\\lib\\" -lMyLib
win32-g++:LIBS += -L"S:\\3rdparty\\DFS.Infrastructure.File\\" -lDFS.Infrastructure.FileSystem
win32-g++:LIBS += -L"S:\\3rdparty\\DFS.Infrastructure.ThreadingW\\" -lDFS.Infrastructure.Threading -lpthreadVC2
}
SOURCES += MainWindow.cpp \
entrypoint.cpp
HEADERS += MainWindow.h
FORMS += MainWindow.ui
OTHER_FILES += ProjectList.txt \
ImageList.txt
Platform:
Windows 7
MinGW
Qt 4.8.3
Qt Creator 2.6.0
[Edit: This answer refers to the original question]
Usually you would add
LIBS += -LS:/3rdparty/DFS.Infrastructure.ThreadingW \
-lpthreadVC2
This adds your library's folder as a library search path (Note the capital -L) and pthreadVC2.lib as a library to link against (lower case -l).
You do not need to add the .dll to the LIBS path, as the .dll is loaded at runtime.
But: This approach only works when the .lib is in the same folder as the .dll. I'm a bit surprised you have yours in different locations.
Maybe adding
LIBS += -LS:/3rdparty
would work, but I'm not sure about that.
In any event, you need to deploy the .dll with your .exe for releases.

qmake not generating binary resource files

Specs: Qt Creator 2.5.1, Qt 4.7.4(32bit)
It is my understanding from the Qt documentation that including a resource (.qrc) in the .pro file of Qt is all that is required to get qmake to generate the correct qrc_*.cpp files. That doesn't seem to be the case for my project. When running qmake the makes files are created and there are references to the qrc_ file I'm looking for under compiler_rcc_clean, just not in the build chain.
[Update]
At a suggestion from comments below the makefile generated by qmake was tested directly w/ NMAKE. The correct qrc_filter_ao.cpp file was created. However the IDE still fails to properly generate this file when I build from Qt Creator.
.pro:
include (../../shared.pri)
TARGET = filter_ao
QT += opengl
HEADERS += ./filter_ao.h
SOURCES += ./filter_ao.cpp
RESOURCES += \
filter_ao.qrc
shared.pri
include (./general.pri)
VCGDIR = ../$$VCGDIR
TEMPLATE = lib
CONFIG += plugin
CONFIG += resources
QT += opengl
QT += xml
QT += xmlpatterns
QT += script
win32-msvc2008: LIBS += ../../distrib/common.lib
win32-msvc2008:DEFINES += GLEW_STATIC _USE_MATH_DEFINES
INCLUDEPATH *= ../.. $$VCGDIR ../$$GLEWDIR/include
DEPENDPATH += ../.. $$VCGDIR
win32-msvc2008:DEFINES += _CRT_SECURE_NO_DEPRECATE
CONFIG(release,debug | release){
# Uncomment the following line to disable assert in mingw
#DEFINES += NDEBUG
}
DESTDIR = ../../distrib/plugins
contains(TEMPLATE,lib) {
CONFIG(debug, debug|release) {
unix:TARGET = $$member(TARGET, 0)_debug
else:TARGET = $$member(TARGET, 0)d
}
}
win32-msvc2008: RCC_DIR = $(ConfigurationName)
general.pri
VCGDIR = ../../../vcglib
GLEWDIR = ../external/glew-1.7.0
win32:DEFINES += NOMINMAX
I think #Pie_Jesu is correct. I have set up a directory structure with the files from the OP, and imported the .pro file into QtCreator. I have removed the "win32-msvc2008: " prefix from the line which sets RCC_DIR since I am using VS Express 2010.
Result was that I get a message like "Unable to open \qrc_filter_ao.cpp for writing: Access denied" and no qrc_file is being created.
I then set the line to /TEMP:
RCC_DIR = /TEMP
Result is that I find the qrc_ file below \TEMP.
Did you try with a simpler .pro file? For instance, the following works for me (On Linux, no MSVC env available currently):
TEMPLATE = lib
CONFIG += plugin
CONFIG += resources
QT += opengl
QT += xml
QT += xmlpatterns
QT += script
TARGET = filter_ao
QT += opengl
RESOURCES += \
filter_ao.qrc
Make sure that the output of from the build contain a call to $QTDIR/rcc, like
/usr/bin/rcc -name filter_ao filter_ao.qrc -o qrc_filter_ao.cpp

Can't find VLC header file

I am trying to compile a VLC-QT program but my compiler says it can't find vlc.h, even though I have included the path in my .pro file. Can anybody tell what's the problem with the following?
QT += core gui
TARGET = vlc
TEMPLATE = app
SOURCES += main.cpp\
vlc_on_qt.cpp
HEADERS += vlc_on_qt.h
INCLUDEPATH += C:\Qt\QT Project\libvlc-qt_0.5.1_win32_sdk\include\
LIBS += -LC:\Qt\QT Project\vlc\libvlc-qt_0.5.1_win32_sdk\lib
LIBS += -lvlc
You need to use #include <vlc/vlc.h> The library stores its header files in a separate directory as most libraries do.

Howto use QCA(http://delta.affinix.com/qca/) with Qt4.7 (Qt Creator)?

I want to use the QCA Library with QT4.7 and QTCreator as IDE.
I downloaded the "qca-2.0.2-mingw" Version and try to link them in my ".Pro"-file:
QT += core
QT -= gui
LIBS += -L"\qca-2.0.2-mingw\lib\"
LIBS += -lqca2
CONFIG *= qt
CONFIG += console
CONFIG -= app_bundle
INCLUDEPATH += "\qca-2.0.2-mingw\include\QtCrypto"
INCLUDEPATH += "\qca-2.0.2-mingw\bin"
TARGET = untitled1
TEMPLATE = app
LINKAGE = -lqca
CONFIG(debug, debug|release) {
windows:LINKAGE = -lqcad
mac:LINKAGE = -lqca_debug
}
LIBS += $$LINKAGE
SOURCES += main.cpp
it compiles but when I run a HMAC sample, copied from this location, http://delta.affinix.com/docs/qca/mactest_8cpp-example.html#_a6
the application stuck with the following error:
Starting C:\Qt\2010.04\qt\untitled1\release\untitled1.exe...
C:\Qt\2010.04\qt\untitled1\release\untitled1.exe exited with code -1073741515
Commenting out some lines doesn't bring the effect. Even the first line of the HMAX Example, will lead to the results described above "QCA::Initializer init;"
I've tried the "qca-2.0.0-mingw" also, but the same effect occurres.
Greets and Thanks first,
Marco
If it builds, that's already good. If it doesn't start, usually DLLs are not found, at runtime. Try adding the path to the qca DLLs to your PATH. In creator you can configure that in the Run Environment section of your Run configuration (Project/Run Settings).

Resources