Brief Technical FAQ

Qt programs need the following components of a Qt distribution:

Header files - Compile time

Programmers need to include the Qt header files. The Qt header files are usually located in the include subdirectory of Qt distributions. Care must be taken to include the header files of the relevant release of Qt. Those with a command-line compiler will typically use options such as /I%QTDIR%\include the relevant release of Qt.

Meta Object Compiler and other tools - Compile time

Programmers need to run moc and other tools such as uic. These tools are usually located in the bin subdirectory of Qt distributions. Either run "$QTDIR"/bin/moc and "$QTDIR"/bin/uic or add "$QTDIR"/bin to your PATH and run moc and uic. If you use qmake the appropriate lines will be added to your Makefiles so that uic and moc will be executed as required.

Static or shared libraries - Link time

Programmers need to link with the Qt static or shared libraries. The Qt libraries are usually located in the lib subdirectory of Qt distributions. Care must be taken to link with the libraries of the relevant release of Qt. Those with a command-line compiler will typically use options such as /L%QTDIR%\lib\qt.lib or -L"$QTDIR"/lib -lqt provided QTDIR specifies the relevant release of Qt.

Shared libraries - Run time

Users of programs linked with shared Qt libraries need these same shared libraries to run these programs. The Qt libraries are usually located in the lib subdirectory of Qt distributions. Shared libraries are made available to programs in places such as C:\windows\system on Windows platforms, directories listed in file /etc/ld.so.conf on Linux, standard lib directories on Unix, or directories listed in environment variables LD_LIBRARY_PATH, SHLIB_PATH, or LIBPATH on various Unix flavours. Make the relevant Qt libraries available using one of these mechanisms.

Qt distributions consist of different files needed at compile time, link time, or run time. Trolltech distributes Qt in the form of a source package that contain all these files once they have been built.

Other vendors distribute Qt in the form of binary packages. Binary packages usually consist of two parts:

• shared libraries in the run time package, usually called qt3.

• header files, static libraries, the moc and other tools in the developers' kit, usually called qt3-dev.

Depending on how you are using Qt, you need to make specific parts of the Qt distribution available to your programs. Typical situations are described below.

Developers building for a single version of Qt on Unix - Qt binary packages

setenv QTDIR /opt/qt-2.3.1
setenv PATH ${QTDIR}/bin:${PATH}

setenv QTDIR /opt/qt-3.0.0
setenv PATH ${QTDIR}/bin:${PATH}

 yourWindow->show();
 yourWindow->setActiveWindow();