qt - Passing an argument to a slot - Stack Overflow I want to override mouseReleaseEvent with a bunch of QActions and QMenus... … So I want to pass an argument to the slot onStepIncreased (as you can imagine they are 1,5,10,25,50). Qt slot with default arguments not working | Qt Forum Having slot private slots: void slot(bool param = true); And connecting QTimer::singleShot(6000, this, &Class:: slot); Creates a compilation error: qglobal.h:121:49: errorno, default arguments for slots is a feature for Qt4 Syntax only, the Qt5 one does not support it, sadly enough. You have two options Passing extra arguments to Qt slots - Eli Bendersky's…
if all arguments and return values are standard C++ or Qt types, the only limitation is a maximum of 10 arguments
Qt Slot Multiple Parameters. Connecting ObjectsQt qt slot multiple parameters Designer's Signals and Slots Editing Mode | Qt Designer Manual. Thread: How to declare qt slot multiple parameters SLOT as a parameter to member function?T qobject_cast( QObject * object ). Your Answer Extremely stuck with passing two arguments to slot | Qt Forum @koahnig said in Extremely stuck with passing two arguments to slot:. @davethedave. Hi and welcome to devnet forum. How many arguments has your signal? If a signal has only one argument, Qt cannot imagine what the second argument shall be. Qt slot with default arguments not working | Qt Forum @JuhaSim said in Qt slot with default arguments not working:. Is this a bug? no, default arguments for slots is a feature for Qt4 Syntax only, the Qt5 one does not support it, sadly enough. You have two options:
@sierdzio said in Signal/slot and const parameters:. I also recommend declaring signals as const. Mixed feeling about this. Qt internally will const_cast the sender if the signal is const so it might be misleading to the user to assume the method is const.
Passing extra arguments to Qt slots - Eli Bendersky's website A few months ago I wrote about passing extra arguments to slots in PyQt.Here, I want to briefly discuss how the same effect can be achieved with Qt itself. C++ is not as dynamic as Python, so Python's approaches of using lambda or functools.partial won't work .Fortunately, the Qt folks provided a solution that can make passing extra arguments to slots relatively simple.
Copied or Not Copied: Arguments in Signal-Slot Connections?
Signals and slots are loosely coupled: A class which emits a signal neither knows nor cares which slots receive the signal. Qt's signals and slots mechanism ensures that if you connect a signal to a slot, the slot will be called with the signal's parameters at the right time. Signals and slots can take any number of arguments of any type. Copied or Not Copied: Arguments in Signal-Slot Connections?
The problem could be how the SW shall decide what the second arguments are. There are more elaborate ways to handle, but I think it is much simpler for you at the time to add another slot routine with only one argument. This may be connected to the combobox. Within this single argument slot you simply call your double argument slot.
If the overloads have different number of arguments, Qt Script will pick the overload with the argument count that best matches the actual number of arguments passed to the slot. Using the Meta-Object Compiler (moc) | Qt 5.12.2
Synchronizing Threads | Qt 5.12 A QMutex forces multiple readers to take turns to read shared data, but a QReadWriteLock allows simultaneous reading, thus improving parallelism. Qt Namespace | Qt Core 5.12.3