building a Qt application outside the Qt sourcetree - qt

Question

I made a simple Qt application that's based on an Qt example application and builds fine from within the "examples" directory of the Qt sourcetree.
Now I want to move my project files to a different location but qmake fails to create a Makefile that can find the Qt header files.
The project files have been moved from ~/qt-everywhere-opensource-src-4.7.2/examples/webkit/fullscreenbrowser to ~/cvswork/fullscreenbrowser/
So the .pro file is now ~/cvswork/fullscreenbrowser/fullscreenbrowser.pro
And the Qt sources are still at ~/qt-everywhere-opensource-src-4.7.2
qmake itself runs fine, but make fails to load some includes:
$ make
g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_WEBKIT_LIB
-DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB
-I/usr/share/qt4/mkspecs/linux-g++
-I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtNetwork
-I/usr/include/qt4/QtGui
-I/usr/include/qt4/QtWebKit
-I/usr/include/qt4
-I.
-o main.o main.cpp
main.cpp:41:17: error: QtGui: No such file or directory
For comparison, when building under the ...examples... directory, the first g++ call is much different:
$ make
g++ -c -pipe -fno-exceptions -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG
-DQT_WEBKIT_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_HAVE_MMX
-DQT_HAVE_3DNOW -DQT_HAVE_SSE -DQT_HAVE_MMXEXT -DQT_HAVE_SSE2 -DQT_HAVE_SSE3
-DQT_HAVE_SSSE3 -DQT_HAVE_SSE4_1 -DQT_HAVE_SSE4_2 -DQT_HAVE_AVX -DQT_SHARED
-I../../../mkspecs/qws/linux-x86-g++
-I.
-I../../../include/QtCore
-I../../../include/QtNetwork
-I../../../include/QtGui
-I../../../include/QtWebKit
-I../../../include
-I.moc/release-shared-emb-x86
-o .obj/release-shared-emb-x86/main.o main.cpp
What do i have to configure so that the Qt source directory is found?
EDIT: The fullscreenbrowser.pro file can be seen here: http://pastebin.com/jUPJiWBC
EDIT2: I get the same behavior in the examples directory when adding -nocache to the qmake call.

Answer 1

That's actually more or less by design I think. Building inside the source folder needs to be a bit different than building against an installed tree, just to be able to do upgrades sanely for instance (prebuild everything in-place without referencing any existing build).
I believe that "trick" is done with a specific .qmake.cache file in the toplevel source folder (~/qt-everywhere-opensource-src-4.7.2 in your case) that is created when you configure the source tree (which happens to build qmake in there).
Try copying that file to your new build location (~/cvswork/fullscreenbrowser/ or ~/cvswork if you have other projects, it should look there too), and re-run qmake (making sure you use the one inside the Qt source directory).
This should work if you've simply configured the source tree.
Here's the first lines of that .qmake.cache file on my machine after having unpacked and configured an old Qt archive:
CONFIG += release shared dll largefile stl precompile_header mmx 3dnow sse sse2 sse3 ssse3 sse4_1 sse4_2 avx dylib create_prl link_prl depend_includepath fix_output_dirs QTDIR_build
QT_SOURCE_TREE = $$quote(/home/foo/src/qt-everywhere-opensource-src-4.7.3)
QT_BUILD_TREE = $$quote(/home/foo/src/qt-everywhere-opensource-src-4.7.3)
QT_BUILD_PARTS = libs tools examples demos docs translations
QMAKE_ABSOLUTE_SOURCE_ROOT = $$QT_SOURCE_TREE
QMAKE_MOC_SRC = $$QT_BUILD_TREE/src/moc
#local paths that cannot be queried from the QT_INSTALL_* properties while building QTDIR
QMAKE_MOC = $$QT_BUILD_TREE/bin/moc
QMAKE_UIC = $$QT_BUILD_TREE/bin/uic
QMAKE_UIC3 = $$QT_BUILD_TREE/bin/uic3
QMAKE_RCC = $$QT_BUILD_TREE/bin/rcc
QMAKE_QDBUSXML2CPP = $$QT_BUILD_TREE/bin/qdbusxml2cpp
QMAKE_INCDIR_QT = $$QT_BUILD_TREE/include
QMAKE_LIBDIR_QT = $$QT_BUILD_TREE/lib
QMAKE_LFLAGS = -Wl,-rpath-link,$$QT_BUILD_TREE/lib $$QMAKE_LFLAGS
QT_CFLAGS_PSQL = -I/usr/include/postgresql-8.4
QT_LFLAGS_PSQL = -L/usr/lib64/postgresql-8.4/lib64
QT_CFLAGS_MYSQL = -I/usr/include/mysql
QT_LFLAGS_MYSQL = -Wl,-O1 -Wl,--as-needed -rdynamic -L/usr/lib64/mysql -lmysqlclient_r -L/usr//lib64 -lz -lpthread -lcrypt -lnsl -lm -lpthread -L/usr/lib64/ -lssl -lcrypto
Q T_LFLAGS_ODBC = -lodbc
QMAKESPEC = $$QT_BUILD_TREE/mkspecs/linux-g++-64
...
As you can see, a lot of the fundamental qmake variables are overridden with that build tree prefix.
(Not sure why you don't simply install Qt somewhere in your home directory. You wouldn't have any of this pain, and you don't need root for that I think as long as the prefix is your own - haven't tried that in ages though, so YMMV.)

Answer 2

The example probably attempts to include a file from elsewhere in the hierarchy. For simple cases you can often generate a new project file as follows:
qmake -project # generate a project file using defaults
qmake # generate a makefile from the project file
make # build using the makefile
qmake will go through your directory recursively examining and including files. It's not smart enough to figure out everything, like every module you may need, but it does a good job on simple test projects. I usually do the above for all my spikes.