Trying to configure qtbase on macOS-26.3

[gav451]

Hello,

I have cloned qtbase from git because I want to explore the examples and I have Qt installed from Home-Brew. When trying to configure building qtbase, I get the error message:

python-3.14.3:0→gav@mbam4:~/VCS/qtbase% ./configure                                    (git)-[dev]-
'/opt/homebrew/bin/cmake' '-DQT_INTERNAL_CALLED_FROM_CONFIGURE:BOOL=TRUE' '-G' 'Ninja' '/Users/gav/VCS/qtbase'
-- CMAKE_BUILD_TYPE was already explicitly set to: 'Release'
CMake Error at cmake/QtPublicAppleHelpers.cmake:1078 (message):
  Can't determine Xcode version.  Is Xcode installed? Error details:

However, I have installed XCode 26.2 which has a binary plist configuration file. I can transform this binary file to a readable xml file with the command

plistutil -i ~/Library/Preferences/com.apple.dt.Xcode.plist -o xcode-plist.xml

but I cannot find anything that looks like an XCode version in this file.

Is the configure script compatible with XCode 26.2?

Thanks in advance.

[IgKh]

Welcome to the forum.

Directly addressing the error is with the xcode-select command to change from the CLI build tools to a full Xcode installation.

However this is not the correct way to go about it; qtbase can't really be configured standalone. Are you building from a source tarball or from git?

(Also, if you just want to build some examples and you already have Qt installed system-wide, there is no need to configure all of Qt source for building. You can just configure and build a single example you are interested in. E.g to build the Widget Gallery example, you can go to ~/VCS/qtbase/examples/widgets/gallery and run qmake or cmake there)

[SGaist]

@IgKh just one small correction: you can definitely build qtbase fully standalone. There's even a helper script that will be installed so that you can then build other modules you want.

@gav451 that said, @IgKh is correct that you don't need to build qtbase yourself to build the demos and examples.

[gav451]

@IgKh
I am building from git and as you said after doing

sudo xcode-select -s /Applications/Xcode.app

I can configure qtbase and do

cmake --build . --parallel

However, building stops with

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX26.2.sdk/usr/include/c++/v1/vector:356:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX26.2.sdk/usr/include/c++/v1/cerrno:33:5: error: <cerrno> tried including <errno.h> but didn't find libc++'s <errno.h> header.           This usually means that your header search paths are not configured properly.           The header search paths should contain the C++ Standard Library headers before           any C Standard Library, and you are probably using compiler flags that make that           not be the case.
   33 | #   error <cerrno> tried including <errno.h> but didn't find libc++'s <errno.h> header. \
      |     ^
In file included from /Users/gav/VCS/qtbase/src/corelib/compat/removed_api.cpp:13:
In file included from /Users/gav/VCS/qtbase/include/QtCore/qmetatype.h:1:
In file included from /Users/gav/VCS/qtbase/src/corelib/kernel/qmetatype.h:16:
In file included from /Users/gav/VCS/qtbase/include/QtCore/qfloat16.h:1:
In file included from /Users/gav/VCS/qtbase/src/corelib/global/qfloat16.h:12:
In file included from /Users/gav/VCS/qtbase/include/QtCore/qmath.h:1:
/Users/gav/VCS/qtbase/src/corelib/kernel/qmath.h:156:12: error: no matching function for call to 'hypot'
  156 |     return hypot(x, y, z);
      |            ^~~~~
/Users/gav/VCS/qtbase/src/corelib/global/qfloat16.h:499:21: note: in instantiation of function template specialization 'qHypot<float, float, float>' requested here
  499 |     return qfloat16(qHypot(float(x), float(y), float(z)));
      |                     ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX26.2.sdk/usr/include/math.h:449:15: note: candidate function not viable: requires 2 arguments, but 3 were provided
  449 | extern double hypot(double, double);
      |               ^     ~~~~~~~~~~~~~~
14 errors generated.
[384/1796] Building CXX object src/3rdparty/harf...ndledHarfbuzz.dir/src/hb-subset-table-layout.cc.o
ninja: build stopped: subcommand failed.

Thanks for the tip on how to build for instance the Widget Gallery example.

[IgKh]

@gav451 For full building of Qt, I'm not sure that the Xcode generator is even supported. Maybe it is, but I personally build with the Ninja generator. I follow the Linux instructions on this page: https://wiki.qt.io/Building_Qt_6_from_Git. It is possible that there other ways.

But then again, you don't really need to.