I got opencv_contrib pack files from github https://github.com/Itseez/opencv_contrib
and built it successfully as the README says ,
$ cmake -DOPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules ..
then I typed make install to generate .so files (Did I misunderstand this command here?) .
But when I use qt to compile this example docs.opencv.org/master/db/d56/tutorial_capture_graycode_pattern.html#gsc.tab=0
it comes error like
undefined reference to `cv::structured_light::GrayCodePattern::Params::Params()'
what should I do?
the following things I've added it in .pro
INCLUDEPATH += /home/tau/opencv/opencv-3.1.0/include /home/tau/opencv/opencv_contrib/modules/structured_light/include
LIBS += -L/usr/local/lib -lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_imgcodecs -lopencv_video -lopencv_videoio-lopencv_structured_light
Related
I'm having a problem with linking FFmpeg libraries to Qt 5.10 Projects.
I downloaded the source code from the official website and successfully compiled and installed to my Ubuntu. I used: ./configure --enable-libvpx --disable-x86asm them: make && make install
I'm able to find the installed libraries in /usr/local/lib (which are .a libs).
my .pro looks like this:
INCLUDEPATH += /usr/local/include
LIBS += -L/usr/local/lib -lavformat -lavcodec -lavutil
but i get the output:
/usr/bin/x86_64-linux-gnu-ld:
/usr/loca/lib/libavformat.a(http.o):undefined reference to symbol 'inflateEnd'
//lib/x86_64-linux-gnu/libz.so.1: error adding symbols: DSO missing from command line
Does anyone know how to solve it? Thanks for the attention!
Note: I would like to static link it to my project
I'm trying to add net-snmp lib to my project using win7 + cygwin:
Project file seems to contain valid lib and path entries:
win32:CONFIG(release, debug|release): LIBS += -L$$PWD/C:/usr/lib/
-lnetsnmp else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/C:/usr/lib/ -lnetsnmpd
INCLUDEPATH += $$PWD/C:/usr/include DEPENDPATH += $$PWD/C:/usr/include
But I can't build the project, because include file is not found, also it exists under given directory physically (c:/usr/include/net-snmp/net-snmp-config.h)
../snmptest1221313123/main.cpp:1:38: fatal error: net-snmp/net-snmp-config.h: No such file or directory
#include
I've read all "add external lib" topics, but it doesn't help to solve this.
Re-running qmake, re-opening Qt creator, or running qmake -r from terminal doesn't help neither.
Remove $$PWD/ (both from include and libs) and try again: run qmake and rebuild.
I am getting an error when trying to link a static boost_filesystem library with QMake.
I know that my boost install is working, because I can link to it no problem outside of QMake like this:
g++ -o my_file my_file.cpp -IC:\boost_1_55_0\boost_1_55_0 -LC:\boost_1_55_0\boost_1_55_0\stage\lib -lboost_system -lboost_filesystem
I tried linking Qt with boost_filesystem like this at first, but it seems that it could not find the libraries:
LIBS += -LC:\boost_1_55_0\boost_1_55_0\stage\lib -lboost_system -lboost_filesystem
"-lboost_system not found -lboost_filesystem not found"
I read something about how you need to specify absolute paths to static libs when using QMake, so I've changes my LIBS line in my .pro to the following:
LIBS += "C:\boost_1_55_0\boost_1_55_0\stage\lib\libboost_system-mgw48-mt-1_55.a" \
"C:\boost_1_55_0\boost_1_55_0\stage\lib\libboost_filesystem-mgw48-mt-1_55.a"
The libraries are found with this method, however I get the following error message:
undefined reference to boost::system::generic_category()
I was under the impression that this error only happen when boost_system isn't linked! I seems like it is linked though, because it finds the proper library for it, and I know my install of boost is good because the same library links fine (with the same compiler) outside of Qt Creator.
Here's the include in mainwindow.h:
include <boost/filesystem.hpp>
Here the full .pro:
QT += core gui
QT += network
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
QMAKE_CXXFLAGS += -std=c++11
TARGET = Downloader
TEMPLATE = app
INCLUDEPATH += C:\boost_1_55_0\boost_1_55_0
LIBS += "C:\boost_1_55_0\boost_1_55_0\stage\lib\libboost_system-mgw48-mt-1_55.a" \
"C:\boost_1_55_0\boost_1_55_0\stage\lib\libboost_filesystem-mgw48-mt-1_55.a"
SOURCES += main.cpp\
mainwindow.cpp\
rar_process.cpp\
HEADERS += mainwindow.h\
rar_process.h\
FORMS += mainwindow.ui
RESOURCES += \
graphics.qrc
And here's the full compiler output:
C:\Qt\Qt5.1.1\5.1.1\mingw48_32\bin\qmake.exe -spec win32-g++ -o Makefile ..\qt- downloader\Downloader.pro
C:/Qt/Qt5.1.1/Tools/mingw48_32/bin/mingw32-make -f Makefile.Release
mingw32-make[1]: Entering directory 'C:/Users/Patrick/Desktop/cpp/build-Downloader- Desktop_Qt_5_1_1_MinGW_32bit-Release'
g++ -Wl,-s -Wl,-subsystem,windows -mthreads -o release\Downloader.exe release/main.o release/mainwindow.o release/rar_process.o release/qrc_graphics.o release/moc_mainwindow.o release/moc_rar_process.o -lglu32 -lopengl32 -lgdi32 -luser32 -lmingw32 -lqtmain C:\boost_1_55_0\boost_1_55_0\stage\lib\libboost_system-mgw48-mt-1_55.a C:\boost_1_55_0\boost_1_55_0\stage\lib\libboost_filesystem-mgw48-mt-1_55.a - LC:\Qt\Qt5.1.1\5.1.1\mingw48_32\lib -lQt5Widgets -lQt5Network -lQt5Gui -lQt5Core
release/main.o:main.cpp:(.text.startup+0x1a): undefined reference to `boost::system::generic_category()'
release/main.o:main.cpp:(.text.startup+0x24): undefined reference to `boost::system::generic_category()'
Makefile.Release:86: recipe for target 'release\Downloader.exe' failed
c:/qt/qt5.1.1/tools/mingw48_32/bin/../lib/gcc/i686-w64-mingw32/4.8.0/../../../../i686- w64-mingw32/bin/ld.exe: release/main.o: bad reloc address 0x24 in section `.text.startup'
collect2.exe: error: ld returned 1 exit status
mingw32-make[1]: *** [release\Downloader.exe] Error 1
mingw32-make[1]: Leaving directory 'C:/Users/Patrick/Desktop/cpp/build-Downloader- Desktop_Qt_5_1_1_MinGW_32bit-Release'
makefile:34: recipe for target 'release' failed
GCC is very sensitive to the order in which you specify libraries during the linking stage. For example, if libA.a depends on libB.a and an executable App depends on both, then you'd have to invoke linker in the following way:
gcc main.o object1.o ... object2.o -lA -lB -o App
This implies that you have to change it to:
LIBS += "C:\boost_1_55_0\boost_1_55_0\stage\lib\libboost_filesystem-mgw48-mt-1_55.a" \
"C:\boost_1_55_0\boost_1_55_0\stage\lib\libboost_system-mgw48-mt-1_55.a"
To be cross-platform, it's recommended to make your build more robust:
Boost_VERSION = 1_55
COMPILER = mgw48
win32-g++* {
LIBS += $$(Boost_DIR)/stage/lib/libboost_filesystem-$${COMPILER}-mt-$${Boost_VERSION}.a \
$$(Boost_DIR)/stage/lib/libboost_system-$${COMPILER}-mt-$${Boost_VERSION}.a
PRE_TARGETDEPS += $$(Boost_DIR)/stage/lib/libboost_filesystem-$${COMPILER}-mt-$${Boost_VERSION}.a \
$$(Boost_DIR)/stage/lib/libboost_system-$${COMPILER}-mt-$${Boost_VERSION}.a
}
linux-g++* {
LIBS += -L$$(Boost_DIR)/stage/lib -lboost_filesystem-$${COMPILER}-mt-$${Boost_VERSION} \
-lboost_system-$${COMPILER}-mt-$${Boost_VERSION}
PRE_TARGETDEPS += $$(Boost_DIR)/stage/lib/libboost_filesystem-$${COMPILER}-mt-$${Boost_VERSION}.a \
$$(Boost_DIR)/stage/lib/libboost_system-$${COMPILER}-mt-$${Boost_VERSION}.a
}
NOTE: Boost_DIR would be treated as an environment variable here. So that you can flexibly build it on any system without hardcoding the system-dependent path to Boost. This is general practice in professional software development: try to hardcode as little as possible in your build system, whatever it is. Furthermore, it's reasonable to even make Boost_VERSION environment variable too. All you'd have to change then, are brackets to parentheses, i.e. $${Boost_VERSION} to $$(Boost_VERSION).
Finally, notice that I've used forward slash / as a path separator for both Windows and Linux. Backward slash \ is not only deprecated in QMake, but it is also discouraged in general. Once again, be cross-platform: simply let QMake handle the conversion.
Apparently boost-system will not link against mingw gcc 4.8.0 if it was built with mingw gcc 4.8.1.
I re-built boost with mingw gcc 4.8.0 and linked against those libs, and now it works!
It's the second day I'm trying to marry Qt5, MinGW and log4cxx.
Even after I've compiled everything successfully, linked apr, apr-util and log4cxx libraries, ld gives me a bunch of "undefined reference" problems.
It looks like different settings were specified during log4cxx compilation (I'm using ant).
Was anyone able to successfully compile and use log4cxx with MinGW?
Environment:
log4cxx trunk
apr 1.4.6
apr-util 1.5.2
latest MinGW
I'm using Qt 5 with latest MinGW as a compiler
What I've done:
compiled log4cxx using ant with the following command: "ant
-Dcompiler=gcc -Dfind=false -DLOG4CXX_STATIC=1 -Dlib.type=static"
added result libraries to my project in pro file: "LIBS +=
-L../log4cxx/lib LIBS += -llibapr-1 -llibaprutil-1 -lliblog4cxx"
And now, as I try to link my project, I'm getting the next:
*C:/mingw/bin/mingw32-make -f Makefile.Debug
mingw32-make[1]: Entering directory 'C:/Work/SPP_Development/AutoHaul/Sub-systems/TCS/Source/build-SimulatorEngine-Standalone_MinGW-Debug'
g++ -Wl,-subsystem,windows -mthreads -o debug\SimulatorEngine.exe object_script.SimulatorEngine.Debug -lmingw32 -lqtmaind -L../log4cxx/lib -llibapr-1 -llibaprutil-1 -lliblog4cxx -LC:\Qt\Qt5.0.1\5.0.1\mingw47_32\lib -lQt5XmlPatternsd -lQt5Widgetsd -lQt5Networkd -lQt5Xmld -lQt5Guid -lQt5Cored -llibEGLd -llibGLESv2d -lgdi32 -luser32
Makefile.Debug:200: recipe for target 'debug\SimulatorEngine.exe' failed
mingw32-make[1]: Leaving directory 'C:/Work/SPP_Development/AutoHaul/Sub-systems/TCS/Source/build-SimulatorEngine-Standalone_MinGW-Debug'
Makefile:34: recipe for target 'debug' failed
../log4cxx/lib/liblog4cxx.lib(mutex.o): In function `ZN7log4cxx7helpers5MutexC2ERNS0_4PoolE':
c:/Work/log4cxx/apache-log4cxx-trunc/src/main/cpp/mutex.cpp:35: undefined reference to `apr_thread_mutex_create#12'
../log4cxx/lib/liblog4cxx.lib(mutex.o): In function `ZN7log4cxx7helpers5MutexC2EP10apr_pool_t':
c:/Work/log4cxx/apache-log4cxx-trunc/src/main/cpp/mutex.cpp:45: undefined reference to `apr_thread_mutex_create#12'
../log4cxx/lib/liblog4cxx.lib(mutex.o): In function `ZN7log4cxx7helpers5MutexD2Ev':
c:/Work/log4cxx/apache-log4cxx-trunc/src/main/cpp/mutex.cpp:55: undefined reference to `apr_thread_mutex_destroy#4'*
It looks like log4cxx library cannot findfunctions declared and defined in the apr library by whatever reason.
Is there any way to analyze the problem further to see why is this happening?
I will describe the 1st problem you have and give the solution for it. If it does not solve your problem, do not revert back because that would be just the 1st step of fixing process, and I will gradually expand the answer to solve more incoming issues as long as you provide relevant feedback on each fix until we finally nail it down. So, lets begin.
First of all, you add libraries into LIBS variable in a wrong way. You have 2 options to do it right:
#1
LIBS += $${PWD}/../log4cxx/lib/libapr-1.a
LIBS += $${PWD}/../log4cxx/lib/libaprutil-1.a
LIBS += $${PWD}/../log4cxx/lib/liblog4cxx-1.a
#2
LIBS += -L$${PWD}/../log4cxx/lib
LIBS += -lapr-1
LIBS += -laprutil-1
LIBS += -llog4cxx-1
NOTE: Of course one liner is possible too:
LIBS += -L$${PWD}/../log4cxx/lib -lapr-1 -laprutil-1 -llog4cxx-1
NOTE: Using line continuation (\) for readability is possible too:
LIBS += -L$${PWD}/../log4cxx/lib \
-lapr-1 \
-laprutil-1 \
-llog4cxx-1
You need to take care of the proper link order: liblog4cxx depends on libapr*, so the libapr entries need to come after liblog4cxx:
LIBS += -L../log4cxx/lib \
-llog4cxx-1 \
-lapr-1 \
-laprutil-1
The reason is that dependencies are resolved left to right, so that in your case the apr libraries have been read, and forgotten, when log4cxx comes along that has some external symbols that need resolving. ld won't read the apr libraries again (has to do with cyclic dependency issues, and historical reasons).
To test if this works, you can try running the command
g++ -Wl,-subsystem,windows -mthreads -o debug\SimulatorEngine.exe object_script.SimulatorEngine.Debug -lmingw32 -lqtmaind -L../log4cxx/lib -lliblog4cxx -llibapr-1 -llibaprutil-1 -LC:\Qt\Qt5.0.1\5.0.1\mingw47_32\lib -lQt5XmlPatternsd -lQt5Widgetsd -lQt5Networkd -lQt5Xmld -lQt5Guid -lQt5Cored -llibEGLd -llibGLESv2d -lgdi32 -luser32
from the directory
C:/Work/SPP_Development/AutoHaul/Sub-systems/TCS/Source/build-SimulatorEngine-Standalone_MinGW-Debug
yourself first. But perhaps just modifying the .pro file is simplest.
I'm developing a Qt application in windows. I have created a lib file in visual studio. I have included the header file containing function prototypes in my Qt App and also added lib file in .pro file as follows
win32: LIBS += -L$$PWD/../Lib/ -lCpLib
INCLUDEPATH += $$PWD/../Lib
DEPENDPATH += $$PWD/../Lib
win32: PRE_TARGETDEPS += $$PWD/../Lib/CpLib.lib
I called the functions from my Qt app. It shows compile error as "undefined reference"
Please help me.
Regards....
The specification of your LIBS is passing linker arguments in gcc format (i.e. using -L to specify the directory and -l to specify the library name).
As you have created your lib file in Visual Studio, you'll need to specify the full library name
e.g.
win32: LIBS += yourlibrary.lib
alternatively, recompile the libraries using MinGW