Signals and Slots (with structure as parameters)

[vishwanath]

Hi

Is there any way to pass structure as parameters for signals and slots

thanks,
vishwa.

[jpn]

Yes, Qt just has to be made aware of the type. See Q_DECLARE_METATYPE and qRegisterMetaType.

[vishwanath]

here is my senario

I have a struct
struct SourceDoneParams_t
{
int eventType;
char* url;
};

Q_DECLARE_METATYPE(mmafwrapper::SourceDoneParams_t );

connected signal/slot something like this
connect(this, SIGNAL(applySourceDone(const mmafwrapper::SourceDoneParams_t)), this,
SLOT(onApplySourceDone(const mmafwrapper::SourceDoneParams_t)));

And I am getting error whenever signal is emmited

QObject::connect Cannot Queue arguments of type 'mmafwrapper::SourceDoneParams_t'

[jpn]

From Q_DECLARE_METATYPE:

Note that if you intend to use the type in queued signal and slot connections, you also have to call qRegisterMetaType() since such connections are resolved at runtime.

[jacek]

struct SourceDoneParams_t
{
...
char* url;
};

Remember that when you send something through a queued connection Qt creates a copy of it, so watch out for that pointer.