Problem with connect invocation

Perdrix

I have a slot called help whose signature was:

public slots:
	void help();

I just changed it to be:

public slots:
	void help(bool startInBackground = false);

and now I get:

FAILED: DeepSkyStacker/CMakeFiles/DeepSkyStacker.dir/ExplorerBar.cpp.o 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++ -DBOOST_CONTAINER_NO_LIB -DBOOST_CONTAINER_STATIC_LINK -DCMS_NO_REGISTER_KEYWORD -DLIBRAW_NODLL -DNOMINMAX -DQT_CORE_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_NO_DEBUG -DQT_WIDGETS_LIB -DUSE_LIBTIFF_STATIC -D_CRT_SECURE_NO_DEPRECATE -I/Users/amonra/.vs/DSS/build/DeepSkyStacker/DeepSkyStacker_autogen/include -I/Users/amonra/.vs/DSS/DeepSkyStacker/. -I/Users/amonra/.vs/DSS/DeepSkyStacker/../DeepSkyStackerKernel -I/Users/amonra/.vs/DSS/DeepSkyStacker/GeneratedFiles/RelWithDebInfo -I/Users/amonra/.vs/DSS/DeepSkyStacker/GeneratedFiles -I/Users/amonra/.vs/DSS/DeepSkyStacker/../ZClass -I/Users/amonra/.vs/DSS/DeepSkyStacker/../Tools -isystem /usr/local/include -isystem /opt/Qt/6.9.1/macos/lib/QtCore.framework/Headers -iframework /opt/Qt/6.9.1/macos/lib -isystem /opt/Qt/6.9.1/macos/mkspecs/macx-clang -isystem /opt/Qt/6.9.1/macos/include -isystem /opt/Qt/6.9.1/macos/lib/QtGui.framework/Headers -isystem /opt/Qt/6.9.1/macos/lib/QtWidgets.framework/Headers -isystem /opt/Qt/6.9.1/macos/lib/QtNetwork.framework/Headers -isystem /Users/amonra/.vs/DSS/build/vcpkg_installed/x64-osx/include -isystem /Users/amonra/.vs/DSS/build/vcpkg_installed/x64-osx/include/libraw -g -Wno-switch-enum -Wno-switch -O2 -g -DNDEBUG -std=c++20 -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.5.sdk -mmacosx-version-min=13.4 -Xclang -fopenmp -Xclang -fopenmp -Winvalid-pch -Xclang -include-pch -Xclang /Users/amonra/.vs/DSS/build/DeepSkyStacker/CMakeFiles/DeepSkyStacker.dir/cmake_pch.hxx.pch -Xclang -include -Xclang /Users/amonra/.vs/DSS/build/DeepSkyStacker/CMakeFiles/DeepSkyStacker.dir/cmake_pch.hxx -MD -MT DeepSkyStacker/CMakeFiles/DeepSkyStacker.dir/ExplorerBar.cpp.o -MF DeepSkyStacker/CMakeFiles/DeepSkyStacker.dir/ExplorerBar.cpp.o.d -o DeepSkyStacker/CMakeFiles/DeepSkyStacker.dir/ExplorerBar.cpp.o -c /Users/amonra/.vs/DSS/DeepSkyStacker/ExplorerBar.cpp
In file included from <built-in>:1:
In file included from /Users/amonra/.vs/DSS/build/DeepSkyStacker/CMakeFiles/DeepSkyStacker.dir/cmake_pch.hxx:5:
In file included from /Users/amonra/.vs/DSS/DeepSkyStacker/pch.h:3:
In file included from /opt/Qt/6.9.1/macos/lib/QtWidgets.framework/Headers/QtWidgets:3:
In file included from /opt/Qt/6.9.1/macos/lib/QtWidgets.framework/Headers/QtWidgetsDepends:3:
In file included from /opt/Qt/6.9.1/macos/lib/QtCore.framework/Headers/QtCore:19:
In file included from /opt/Qt/6.9.1/macos/lib/QtCore.framework/Headers/qabstractanimation.h:7:
/opt/Qt/6.9.1/macos/lib/QtCore.framework/Headers/qobject.h:271:28: error: no matching function for call to 'makeCallableObject'
  271 |                            QtPrivate::makeCallableObject<Func1>(std::forward<Func2>(slot)),
      |                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/amonra/.vs/DSS/DeepSkyStacker/ExplorerBar.cpp:92:3: note: in instantiation of function template specialization 'QObject::connect<void (QLabel::*)(const QString &), void (DeepSkyStacker::*)(bool)>' requested here
   92 |                 connect(ui->help, &QLabel::linkActivated, DeepSkyStacker::instance(), &DeepSkyStacker::help);
      |                 ^
/opt/Qt/6.9.1/macos/lib/QtCore.framework/Headers/qobjectdefs_impl.h:604:5: note: candidate template ignored: requirement 'QtPrivate::countMatchingArguments() >= 0' was not satisfied [with Prototype = void (QLabel::*)(const QString &), Functor = void (DeepSkyStacker::*)(bool)]
  604 |     makeCallableObject(Functor &&func)
      |     ^
1 error generated.

from this line:

		connect(ui->help, &QLabel::linkActivated, DeepSkyStacker::instance(), &DeepSkyStacker::help);

so clearly I need to change it, but what to?

If this is obvious - put it down to my not having had enough coffee yet.
Thanks
David

SGaist

Hi,

You are trying to connect a signal with a string parameter to a slot with a boolean one.

If you really want to do that, you should use a lambda.

Perdrix

@SGaist Thank you! This seems to work (well at least it compiles)!

		auto deepSkyStacker = DeepSkyStacker::instance();

		connect(ui->help, &QLabel::linkActivated, deepSkyStacker, [=]() { deepSkyStacker->help(); });

David