SDK (isysroot) selection "rules"? (Qt5 related)

[Ned Deily]

In article <3556574.Un4NXkj1da at patux>,
 Rene J.V. Bertin <rjvbertin at gmail.com> 
 wrote:
> On Thursday June 18 2015 10:31:04 Ryan Schmidt wrote:
> >Xcode projects often include hardcoded values for the SDK, deployment 
> >target, and architectures, so if this is using an Xcode project file, check 
> >for that. If not, check the project's build system. 
> No, it doesn't use Xcode; it uses qmake. I think I'm discovering that Qt's 
> own build system is the culprit; it has to be configured with -sdk macosx10.9 
> or else it will use the 10.10 SDK. It's too early to confirm if that indeed 
> resolves the missing symbol issue I've been seeing in Qt Creator but initial 
> testing with manual compilation of the file using the symbol suggests it 
> should. I'm no longer seeing -isysroot calling for the 10.10 sdk but rather 
> the 10.9 sdk.

FWIW, if you are using the most recent Xcode installation for OS X 10.9, 
you'll find that the default SDK for OS X ("macosx") is 10.10.  That's 
probably because Apple recommends that you use the SDK for the most 
recent OS X release and that your code tests for feature availability if 
it is to run on earlier systems, like when MACOSX_DEPLOYMENT_TARGET is 
set to an earlier version.

$ sw_vers
ProductName:   Mac OS X
ProductVersion:   10.9.5
BuildVersion:  13F1077

$ xcodebuild -version
Xcode 6.1.1
Build version 6A2008a

$ xcodebuild -version -sdk macosx
MacOSX10.10.sdk - OS X 10.10 (macosx10.10)
SDKVersion: 10.10
Path: 
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Deve
loper/SDKs/MacOSX10.10.sdk
PlatformVersion: 1.1
PlatformPath: 
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform
ProductBuildVersion: 14A382
ProductCopyright: 1983-2014 Apple Inc.
ProductName: Mac OS X
ProductUserVisibleVersion: 10.10
ProductVersion: 10.10

$ xcodebuild -version -sdk macosx10.9
MacOSX10.9.sdk - OS X 10.9 (macosx10.9)
SDKVersion: 10.9
Path: 
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Deve
loper/SDKs/MacOSX10.9.sdk
PlatformVersion: 1.1
PlatformPath: 
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform
ProductBuildVersion: 13F26
ProductCopyright: 1983-2014 Apple Inc.
ProductName: Mac OS X
ProductUserVisibleVersion: 10.9.5
ProductVersion: 10.9.5

-- 
 Ned Deily,
 nad at acm.org