Install old version PyQt4 on a mac by compiling the source

[Phil Thompson]

On 08/07/2021 19:37, Felix Voigt wrote:
> Hello everyone,
> 
> today I tried the same with PyQt5 with the following results.
> 
> The configure process succeeded:
> cd ~/documents/tmp/PyQt5-5.15.4
> ~/.pyenv/versions/2.7.18/bin/python2.7 configure.py --qmake
> /usr/local/Cellar/qt at 5/5.15.2/bin/qmake
> --sip=/Users/felixvoigt/.pyenv/versions/2.7.18/bin/sip --verbose
> 
> The make process failed:
> make
> -> In file included from
> /Users/felixvoigt/documents/tmp/PyQt5-5.15.4/sip/QtCore/qsocketnotifier.sip:26:
> 
> /usr/local/Cellar/qt at 5/5.15.2/lib/QtCore.framework/Headers/qsocketnotifier.h:117:35:
> error: constexpr function never produces a constant
>       expression [-Winvalid-constexpr]
>     Q_DECL_CONSTEXPR_NOT_WIN bool isValid() const noexcept { return
> *this != QSocketDescriptor(); }
>                                   ^
> 
> /usr/local/Cellar/qt at 5/5.15.2/lib/QtCore.framework/Headers/qsocketnotifier.h:117:75:
> note: undefined function 'operator!=' cannot be used
>       in a constant expression
>     Q_DECL_CONSTEXPR_NOT_WIN bool isValid() const noexcept { return
> *this != QSocketDescriptor(); }
>                                                                         
>   ^
> 
> /usr/local/Cellar/qt at 5/5.15.2/lib/QtCore.framework/Headers/qsocketnotifier.h:124:42:
> note: declared here
>     friend Q_DECL_CONSTEXPR_NOT_WIN bool operator!=(QSocketDescriptor 
> lhs,
> 1 error generated.
> 
> Any ideas how to fix it?
> Kind regards
> feli_x

As the error is referring to Qt source code and not SIP generated code 
then the problem may be your version of Xcode.

Phil