- Qt 5.15
- Qt for Linux/X11 - Building from Source
- Qt 5.15.12 Reference Documentation

# Qt for Linux/X11 - Building from Source

You can download the Qt 5 sources from the Downloads page. For more information, visit the Getting Started with Qt page.

Qt for X11 has some requirements that are given in more detail in the Qt for X11 Requirements document.

## Step 1: Installing the License File (Commercially Licensed Qt Only)

If you use Qt with a commercial license, the Qt tools look for a local license file. If you are using a binary installer or the commercial Qt Creator, your licenses are automatically fetched and stored in your local user profile (`$XDG_DATA_HOME/Qt/qtlicenses.ini` file).

If you do not use any binary installer or Qt Creator, you can download the respective license file from your Qt Account Web portal and save it to your user profile as `$HOME/.qt-license`. If you prefer a different location or file name, you need to set the `QT_LICENSE_FILE` environment variable to the respective file path.

## Step 2: Unpacking the Archive

Unpack the archive if you have not done so already. For example, if you have the `qt-everywhere-opensource-src-%VERSION%.tar.gz` package, type the following commands at a command line prompt:

     cd /tmp
     gunzip qt-everywhere-opensource-src-%VERSION%.tar.gz        # uncompress the archive
     tar xvf qt-everywhere-opensource-src-%VERSION%.tar          # unpack it

This creates the directory `/tmp/qt-everywhere-opensource-src-%VERSION%` containing the files from the archive. We only support the GNU version of the tar archiving utility. Note that on some systems it is called gtar.

## Step 3: Building the Library

To configure the Qt library for your machine type, run the `./configure` script in the package directory.

By default, Qt is configured for installation in the `/usr/local/Qt-%VERSION%` directory, but this can be changed by using the `-prefix` option.

     cd /tmp/qt-everywhere-opensource-src-%VERSION%
     ./configure

The Configure Options page contains more information about the configure options.

To create the library and compile all the examples, tools, and tutorials, type:

     make

If `-prefix` is outside the build directory, you need to install the library, examples, tools, and tutorials in the appropriate place. To do this (as root if necessary), type:

     make install

Note that on some systems the make utility is named differently, like gmake. The configure script tells you which make utility to use.

Note: Later, if you need to reconfigure and rebuild Qt from the same location, ensure that all traces of the previous configuration are removed. To do so, from the build directory, type `make confclean` before running `configure` again.

## Step 4: Set the Environment Variables

To use Qt, some environment variables need to be extended.

     PATH               - to locate qmake, moc and other Qt tools

This is done as follows:

In `.profile` (if your shell is bash, ksh, zsh or sh), add the following lines:

     PATH=/usr/local/Qt-%VERSION%/bin:$PATH
     export PATH

In `.login` (if your shell is csh or tcsh), add the following line:

     setenv PATH /usr/local/Qt-%VERSION%/bin:$PATH

If you use a different shell, modify your environment variables accordingly.

For compilers that do not support rpath you must also extend the `LD_LIBRARY_PATH` environment variable to include `/usr/local/Qt-%VERSION%/lib`. On Linux with GCC this step is not needed.

## Step 5: Build the Qt Documentation

For the Qt reference documentation to be available in Qt Assistant, you must build it separately:

     make docs