On 07/31/2014 11:47 PM, Bruce Dubbs wrote: > Armin K. wrote: >> On 07/31/2014 11:23 PM, Bruce Dubbs wrote: >>> Armin K. wrote: >>>> On 07/31/2014 11:10 PM, Bruce Dubbs wrote: >>>>> Armin K. wrote: >>>>>> The >>>>>> changes include rewritten Qt4 and Qt5 instructions so they can be >>>>>> once >>>>>> again installed alongside each other in /usr, using qtchooser to >>>>>> dynamically switch between two installations. The instructions were >>>>>> also >>>>>> simplified so that only one configure line is there and prefix can be >>>>>> changed before running it. >>>>> >>>>> I'm curious. If there are two users on the system and user1 wants to >>>>> build some packages using qt4 and user2 wants to build using qt5, >>>>> how is >>>>> that possible with qtchooser? >>>>> >>>>> And yes, I've been in that situation, although it was qt3/qt4 at the >>>>> time. >>> >>>> http://www.linuxfromscratch.org/~krejzi/blfs-systemd/x/qt4.html >>>> >>>> See "Dealing with multiple Qt versions". I believe this was the only >>>> significant improvement over the previous instructions that used >>>> qtchooser. >>> >>> That's not clear to me that it solves the problem. I haven't looked at >>> qtchooser recently, but I thought it created symbolic links so that it >>> changed the current default qt version for everyone. That means that >>> all developers on a system must use the same qt version unless >>> qtchoosser is run again. >>> >>> Please correct me if I don't understand properly. > >> No. >> >> qtchooser is a small utility. The Qt programs such as qmake, moc, uic, >> etc are symlinks to qtchooser and always in PATH. Depending on the >> configuration file or environment variable, qtchooser can be made to use >> Qt executables and libraries from different paths. >> >> Configuration file only sets the default, which is always Qt4 in that >> setup, because most programs that use Qt5 look for executables with -qt5 >> suffix. >> >> There is no good way for me to explain how it does things, but I believe >> this is the simplest: It does not change symlinks. It is basically a >> wrapper for Qt executables which can be used to switch between different >> Qt versions *without* a need to change either symlinks or PATH variable, >> by merely setting a environment variable for default Qt setup >> (QT_SELECT=qt4 ; qmake = Qt4 qmake (default), export QT_SELECT=qt5 ; >> qmake = Qt5 qmake). > > OK. I see what you are saying. What we have in trunk adjusts the PATH, > while qtchooser uses an environment variable and a wrapper. > > Different people have different preferences. I feel the trunk method of > adjusting the PATH is more straight forward, but I understand your > preference too. > > -- Bruce >
Right. It's also the upstream way and some packages may rely on it. -- Note: My last name is not Krejzi.
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