[Development] Co-installation & executable naming rules

[Thiago Macieira]

On segunda-feira, 24 de setembro de 2012 07.19.30, Ziller Eike wrote:
> I don't think the recommendation applies to Mac.
> 
> Usually you won't have globally installed Qt. Most applications deploy their
> used libraries within the application's app bundle (that's what we have
> macdeployqt for). Even if someone installs Qt globally it will be as
> frameworks, not dylibs, and frameworks already have a versioning scheme
> that includes major versions as binary incompatible versions of frameworks,
> and has all major versions in separate directories (within the framework
> bundle).
> http://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPF
> rameworks/Concepts/VersionInformation.html
> 
> The frameworks + libraries + tools used for development are not installed in
> system directories (/usr/bin and so on), but separately.
> 
> E.g. Xcode installs the frameworks + libraries + tools for the different SDK
> versions (e.g. Mac OS X 10.6 vs 107) in different prefixes (nowadays even
> within the Xcode app bundle). The ones referring to the versions currently
> installed on the system might just be symbolic links, but point is that
> they are usually used from these special prefixes. Nowadays you even need
> to explicitly install the compilers etc in /usr/bin if you really want them
> there. For Qt this means it is perfectly fine to either only have "user"
> installations of the development stuff (~/QtSDK/...), or to install to
> different prefixes for different binary incompatible versions, like we had
> in the old binary packages in /usr/local/Qt4/... /usr/local/Qt5/...

Hi Eike

Thank you for the explanation. Looks like Mac has solved the co-installation 
problem differently.

Let me ask you a question, though: suppose someone installs Qt 5 globally as 
frameworks (/System/Frameworks/QtCore.framework), then updates Qt 4.8. Which 
is the default symlink target?

And how does one select, at compile time, whether to compile & link to Qt 4 or 
to Qt 5?

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center
     Intel Sweden AB - Registration Number: 556189-6027
     Knarrarnäsgatan 15, 164 40 Kista, Stockholm, Sweden
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