new FAQ entry: several Qt versions(was: Re: Ghost points in small app & question about using qt 2.0.1 libs.)

[Ken Brakey]

Falk Brettschneider wrote:

> Jeremy Webster wrote:
> >     One other question.  Now that I have all the qt 1.44 libs working, how
> > do I make it so that I can also use the qt 2.0.1 libs?  I was going through
> > some of the toots over at Qt and they seem to really like qvbox.h and some
> > other things that apparently aren't in the 1.44 set.   I tried fiddling
> > around in the Project Options menu with no success.  Is any of this
> > documented anywhere?
>
> Q: I want to develop with a newer Qt version than provided
>    with my current Unix distribution. How do I do that?
> A: Some things has to be done:
>    1.) The newer Qt version must be installed parallely.
>        [ For instance like this: /usr/lib/qt-1.44
>                                  and
>                                  /usr/lib/qt-2.0.2  ]

OOPS! --- KDE2 will be, aparantly,  built with qt-2.1 or higher.
DON't use 2.0.X for anything, (except reserving disk space).
This may be (or cause ) a delay for KDE2.


>
>    2.) The compiler looks in /usr/local/qt or /usr/lib/qt
>        while deciding for the right headers of a Qt library.
>        The link
>           /usr/local/qt --> /usr/lib/qt
>        is set in most of all cases.
>
>        That's why you just need to set one of these links
>        to tell the compiler what to choose:
>           /usr/lib/qt --> /usr/lib/qt-2.0.2
>             (for compiling Qt2 programs)
>           /usr/lib/qt --> /usr/lib/qt-1.44
>             (for compiling Qt1.44 programs)
>
>        The command for setting the link is:
>           ln -s /usr/lib/qt /usr/lib/qt-2.0.2
>        or
>           ln -s /usr/lib/qt /usr/lib/qt-1.44
>
>    3.) To make sure that the linker find the right lib simply
>        switch to user "root" and add two lines in /etc/ld.so.conf :
>           /usr/lib/qt-2.0.2/lib
>           /usr/lib/qt-1.44/lib
>        and run:
>           /sbin/ldconfig -v
>
> --
>
> Ciao,
> --Falk