Program hangs when i emit a global variable (Solved)

[houmingc]

A qt statement connect Slot and Signals together. Like to understand how variable qint8
is pass from Signals functions to Slot functions.

@
extern qint8 myvalue; //in slots cpp
connect(UdpReceived, SIGNAL(TriggerReceived(qint8)), this, SLOT(TriggerSlot(qint8))) //constructor

signals:
void TriggerReceived(qint8 myvalue); //declaration, in signals .h

qint8 myvalue //global value
emit TriggerReceived( myvalue); //definition, in signals .cpp

Or =====
public:
qint8 myvalue; //signals .h

@

i understand moc(meta object compiler) connects them together but how is varaible pass?
The reason is because i declare variable-myvalue as global instead as class public variable.
The program hangs either i emits this global or public variable

Please enlighten me.

[houmingc]

Could pass variable through connecting two objects but could not pass variables using extern. Why ??

@
connect(UdpReceived, SIGNAL(TriggerReceived(qint8)), this, SLOT(TriggerSlot(qint8)))
@

I could not pass variables using extern

@
extern qint8 m_valuetopass

connect(UdpReceived, SIGNAL(TriggerReceived()), this, SLOT(TriggerSlot()))
@

signal has no implementation, but "emit TriggerReceived( myvalue)" is not declaration, either.

[houmingc]

Thanks, Initially i did not emit a signal with parameter by value. I use a global value to pass between 2 cpp files.