TQSignal Class

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# TQSignal Class Reference

The TQSignal class can be used to send signals for classes that don't inherit TQObject. More...

`#include <tqsignal.h>`

Inherits TQObject.

List of all member functions.

## Public Members

- TQSignal ( TQObject * parent = 0, const char * name = 0 )
- ~TQSignal ()
- bool connect ( const TQObject * receiver, const char * member )
- bool disconnect ( const TQObject * receiver, const char * member = 0 )
- void activate ()
- void setValue ( const TQVariant & value )
- TQVariant value () const

## Detailed Description

The TQSignal class can be used to send signals for classes that don't inherit TQObject.

If you want to send signals from a class that does not inherit TQObject, you can create an internal TQSignal object to emit the signal. You must also provide a function that connects the signal to an outside object slot. This is how we have implemented signals in the TQMenuData class, which is not a TQObject.

In general, we recommend inheriting TQObject instead. TQObject provides much more functionality.

You can set a single TQVariant parameter for the signal with setValue().

Note that TQObject is a private base class of TQSignal, i.e. you cannot call any TQObject member functions from a TQSignal object.

Example:

            #include <tqsignal.h>

            class MyClass
            {
            public:
                MyClass();
                ~MyClass();

                void doSomething();

                void connect( TQObject *receiver, const char *member );

            private:
                TQSignal *sig;
            };

            MyClass::MyClass()
            {
                sig = new TQSignal;
            }

            MyClass::~MyClass()
            {
                delete sig;
            }

            void MyClass::doSomething()
            {
                // ... does something
                sig->activate(); // emits the signal
            }

            void MyClass::connect( TQObject *receiver, const char *member )
            {
                sig->connect( receiver, member );
            }

See also Input/Output and Networking and Miscellaneous Classes.

## Member Function Documentation

### TQSignal::TQSignal ( TQObject * parent = 0, const char * name = 0 )

Constructs a signal object called name, with the parent object parent. These arguments are passed directly to TQObject.

### TQSignal::~TQSignal ()

Destroys the signal. All connections are removed, as is the case with all TQObjects.

### void TQSignal::activate ()

Emits the signal. If the platform supports TQVariant and a parameter has been set with setValue(), this value is passed in the signal.

### bool TQSignal::connect ( const TQObject * receiver, const char * member )

Connects the signal to member in object receiver.

See also disconnect() and TQObject::connect().

### bool TQSignal::disconnect ( const TQObject * receiver, const char * member = 0 )

Disonnects the signal from member in object receiver.

See also connect() and TQObject::disconnect().

### void TQSignal::setValue ( const TQVariant & value )

Sets the signal's parameter to value

### TQVariant TQSignal::value () const

Returns the signal's parameter

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