Question

I’m trying to compile a small application using Qt but without using QMake, but whenever I try to run it, I get the following error message:

g++ -c -g -pg -Wall -Wextra -pipe   -c -o ../../MOCFiles/moc_projectModel.o ../../MOCFiles/moc_projectModel.cpp
In file included from ../../MOCFiles/moc_projectModel.cpp:10:0:
../../MOCFiles/../Src/ProjectStructure/projectModel.h:4:30: fatal error: QAbstractItemModel: No such file or directory
compilation terminated.
make: *** [../../MOCFiles/moc_projectModel.o] Error 1

This would seem to suggest that I haven’t constructed my $(INCLUDE) variable properly, but it is as follows:

INCLUDE   = -I/usr/include/qt4 \
            -I/usr/include/qt4/QtGui \
            -I/usr/include/qt4/QtCore \
            -I/usr/include/qt4/QtXml \
            -I/usr/share/qt4/mkspecs/linux-g++ \
            -I../../Src/ProjectStructure 

and I am able to locate the QAbstractItemModel file in /usr/include/qt4/QtCore/, a directory which is part of my include variable. This is my first time writing a GNU Makefile and I’m not sure what it is I’m doing wrong. For reference, the entire file is included here:

CXX       = g++
CXXFLAGS  = -c -g -pg -Wall -Wextra -pipe
LINK      = g++

LIBS      = -L/usr/lib \
            -L/usr/lib/i386-linux-gnu \
            -lgtest \
            -lQtGui \
            -lQtCore \
            -lQtXml \
            -lpthread

INCLUDE   = -I/usr/include/qt4 \
            -I/usr/include/qt4/QtGui \
            -I/usr/include/qt4/QtCore \
            -I/usr/include/qt4/QtXml \
            -I/usr/share/qt4/mkspecs/linux-g++ \
            -I../../Src/ProjectStructure

OBJECTS = ../Objects/main.o \
          ../Objects/test_projectEntity.o \
          ../Objects/moc_test_projectModel.o \
          ../../Objects/projectEntity.o \
          ../../Objects/projectModel.o \
          ../../MOCFiles/moc_projectModel.o

../../Binaries/tests: $(OBJECTS)
  $(LINK) $^ $(LIBS) -o $@

../Objects/main.o : ../Src/main.cpp
  $(CXX) $(CXXFLAGS) $(INCLUDE) ../Src/main.cpp -o ../Objects/main.o

../Objects/moc_test_projectModel.o : ../MOCFiles/moc_test_projectModel.cpp
  $(CXX) $(CXXFLAGS) $(INCLUDE) ../MOCFiles/moc_test_projectModel.cpp -o ../Objects/moc_test_projectModel.o

../../MOCFiles/moc_test_projectModel.cpp :  ../Src/test_projectModel.cpp
  moc ../Src/test_projectModel.cpp -o ../MOCFiles/moc_test_projectModel.cpp

../Objects/test_projectEntity.o : ../Src/test_projectEntity.cpp
  $(CXX) $(CXXFLAGS) $(INCLUDE) ../Src/test_projectEntity.cpp -o ../Objects/test_projectEntity.o

clean:
  rm -f ../Objects/main.o ../Objects/test_projectEntity.o ../Objects/test_projectModel.o

Answer 1

It looks as if you’re trying to build ../../Binaries/tests. One of the preqs is ../../MOCFiles/moc_projectModel.o, but there’s no explicit rule for building that, so Make uses the implicit rule and attempts this:

g++ -c -g -pg -Wall -Wextra -pipe   -c -o ../../MOCFiles/moc_projectModel.o ../../MOCFiles/moc_projectModel.cpp

Notice that there’s no mention of INCLUDE there. So g++ doesn’t know to look in /usr/include/qt4/QtCore/. The simple solution is to add a rule:

../../MOCFiles/moc_projectModel.o : ../../MOCFiles/moc_projectModel.cpp
    $(CXX) $(CXXFLAGS) $(INCLUDE) $< -o $@

Notice that I used automatic variables $< and $@ there, to reduce redundancy and clutter. We could also make it into a pattern rule:

../../MOCFiles/%.o : ../../MOCFiles/%.cpp
    $(CXX) $(CXXFLAGS) $(INCLUDE) $< -o $@

This takes care of moc_projectModel.o and anything else that has the same pattern (source and object both in MOCFiles/). We could make other improvements, but that should be enough to get you up and running.