Qt4 Installation for GUI

It must be installed before Qwt. A Qt version equal or higher than 4.6 is required. One can install it:

• via YUM:

   yum install qt-devel
  

• via download from:
  https://download.qt.io/archive/qt/4.8/4.8.2/qt-everywhere-opensource-src-4.8.2.t ar.gz

  To install:

  > gunzip qt-everywhere-opensource-src-4.8.2.tar.gz
  > tar xvf qt-everywhere-opensource-src-4.8.2.tar
  > ./configure
  > make
  > make install
  

  By default Qt4 will be installed in /usr/local/Trolltech/Qt-4.8.2/.

Setup Environment

One has to ensure that PATH and LD_LIBRARY_PATH have been updated to include Qt4 install path, binaries and libraries. Confirm by executing qmake -v and ensuring the result points to Qt4 (not Qt3 or Qt5).

If the environment is not set up, one can add the libraries and executables to the .bashrc by adding LD_LIBRARY_PATH and PATH:

export QTDIR=/usr/local/Trolltech/Qt-4.8.2
export PATH=$QTDIR/bin:$PATH
export LD_LIBRARY_PATH=$QTDIR/lib:$LD_LIBRARY_PATH