Search code examples
qtqmake

Why doesn't qmake include library files?

I am trying to link a third party library to my Qt project. Here is my .pro file:

TEMPLATE = app
TARGET = camera_ui

QMAKE_LFLAGS += -Wl --enable-new-dtags -Wl -rpath /opt/pylon5/lib64
INCLUDEPATH += -I/opt/pylon5/include

LIBS += -L/opt/pylon5/lib64 -Wl -E \
       -lpylonbase \
       -lpylonutility \
       -lGenApi_gcc_v3_0_Basler_pylon_v5_0 \
       -lGCBase_gcc_v3_0_Basler_pylon_v5_0 \
       -lopencv_core \
       -lopencv_highgui

# Input
HEADERS += basler_opencv_utils.h camera_interface.h mainwindow.h
FORMS += mainwindow.ui
SOURCES += basler_opencv_utils.cc main.cpp mainwindow.cpp

But here is the output after running qmake then make.

g++ -c -m64 -pipe -O2 -Wall -W -D_REENTRANT -fPIC -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -I. -I-I/opt/pylon5/include -isystem /usr/include/x86_64-linux-gnu/qt5 -isystem /usr/include/x86_64-linux-gnu/qt5/QtGui -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore -I. -I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++-64 -o basler_opencv_utils.o basler_opencv_utils.cc
basler_opencv_utils.cc:5:33: fatal error: pylon/PylonIncludes.h: No such file or directory
compilation terminated.
Makefile:373: recipe for target 'basler_opencv_utils.o' failed
make: *** [basler_opencv_utils.o] Error 1

Notice that the INCLUDE_PATH works, but the LIBS and QMAKE_LFLAGS are not included in the build command. I've looked at this and this but those didn't solve my problem. I've also tried adding TARGETDEPS += libpylonbase.so as per this question, with no change.

I also tried using Qt Creator to make the .pro file for my, but I couldn't figure out what I was supposed to enter into the wizard in the "library files" field.

UPDATE: I was able to get it working with some help from the section below. If anyone else is trying to use the Basler Pylon SDK with QT5 here is a working make file (includes OpenCV as well).

QT += core gui widgets

TEMPLATE = app
TARGET = camera_ui
PYLON_ROOT = /opt/pylon5
# Input
HEADERS += basler_opencv_utils.h camera_interface.h mainwindow.h
FORMS += mainwindow.ui
SOURCES += basler_opencv_utils.cc main.cpp mainwindow.cpp

QMAKE_CPPFLAGS += /opt/pylon5/include
QMAKE_CXXFLAGS += -Wno-unknown-pragmas -Wno-unused-parameter -Wno-unused-variable
QMAKE_LFLAGS_RPATH += -Wl,--enable-new-dtags -Wl,-rpath,/opt/pylon5/lib64

INCLUDEPATH += /opt/pylon5/include
INCLUDEPATH += /opt/pylon5/lib64

LIBS += /opt/pylon5/lib64 -Wl,-E -lpylonbase -lpylonutility -lGenApi_gcc_v3_0_Basler_pylon_v5_0 -lGCBase_gcc_v3_0_Basler_pylon_v5_0
LIBS += -lopencv_core -lopencv_highgui
Solution

    1. No, your INCLUDEPATH doesn't work. Your include is INCLUDEPATH += -I/opt/pylon5/include which resolves to -I-I/opt/pylon5/include correct (-I/opt/pylon5/include) and that is an invalid directory. -I must be removed from INCLUDEPATH. The header file PylonIncludes.h is expected to be in/opt/pylon5/include/pylon/PylonIncludes.h

    2. The correct path to include a library is

      LIBS += -L"/home/directory" -lmylibrary -mylibrary2 - If the library is not found, the compiler throws an error.

      LIBS += -L/opt/pylon5/lib64 -Wl -E \ is invalid and truncates probably the libraries after -WL -E \

    3. You linker flags: QMAKE_LDFLAGS is correct. QMAKE_LFLAGS += -Wl etc. Why you don't see it in the g++ command line? It's the compiler not the linker, you error out before.