		Choice of Development Library
		-----------------------------

SoQt extends Qt, and Debian ships two flavours of SoQt: one linked
against Qt3 and one linked against Qt4.  Developers must install
the right packages and take care in how they build applications.

Users do not have to read any further.

SoQt is built on top of OpenInventor and Qt, and therefore links
with each.  Read the following to determine which packages are 
right for you.


	OpenInventor
	------------

As at this writing, Debian has three OpenInventor libraries: the
original implementation from SGI, and two versions of Coin (1.x and
2.x, which has a different license and enhanced functionality), an
independent rewrite.

All three are source-code (API) compatible, but only Coin v2 is
actively maintained, so SoQt is built against Coin v2.


	Qt
	--

Similarly, Debian contains versions 3 and 4 of the Qt library.  Both
are actively used, so SoQt comes in two flavours: 

1. libsoqt3-dev contains the SoQt devel. environment linked with Qt3
2. libsoqt4-dev contains the SoQt devel. environment linked with Qt4


Both -dev packages may be installed simultaneously.


Linking
-------

The libraries may be linked using -lSoQt3 and -lSoQt4, for Qt3 and
Qt4, respectively.

For compatibility with upstream and with previous versions of the
Debian packages, the "alternatives" mechanism provides the undecorated
link library, accessed using "-lSoQt".  

If you install only one of the -dev packages, -lSoQt will refer to the
installed version.  If you install both -dev packages, -lSoQt will by
default refer to SoQt4.  You may change the system default using the
command "update-alternatives" as root.


soqt-config
-----------

This script may be invoked using option --alternate=qt3 and
--alternate=qt4, for Qt3 and Qt4, respectively.

A default soqt-config is also provided, using "alternatives".  If you
install only one of the -dev packages, soqt-config will refer to the
installed version.  If you install both -dev packages, soqt-config
will by default refer to SoQt4.  You may change the system default
using the command "update-alternatives" as root.


 -- Steve M. Robbins <smr@debian.org>, Tue, 22 Apr 2008 22:47:14 z
