Qt Signals and Slots object disconnect?

Question

I am wondering if i need to disconnect singals and slots if i destroy the signal emitting object. Here is an example:

QAudioOutput * audioOutput = new QAudioOutput(format,mainWindow);
connect(audioOutput,SIGNAL(stateChanged(QAudio::State)),this,SLOT(stateChanged(QAudio::State)));

delete audioOutput;

audioOutput = new QAudioOutput(format,mainWindow);
connect(audioOutput,SIGNAL(stateChanged(QAudio::State)),this,SLOT(stateChanged(QAudio::State)));

Will this automatically disconnect the signal from the old audioOutput, or will it lead to mem leaks or some other undefined behavior ?

Thank you in advance.

Although `QObject`s safely clean up connections when they are destroyed I would recommend against deleting a `QObject` that has already had its parent set as you have above since this will short circuit the automatic mechanisms already in place for `QObject`s. It is also generally safer to use `deleteLater()` instead of deleting a `QObject` directly. — Arnold Spence, Feb 13 '12 at 17:30

score 40 · Accepted Answer · edited Jun 30 '15 at 12:15

40

The signals are automatically disconnected when you call the QObject destructor. Have a look at the Qt documentation: QObject Destructor

edited Jun 30 '15 at 12:15

Yakov Galka

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answered Feb 13 '12 at 17:19

Adrien BARRAL

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score 4 · Answer 2 · edited Sep 08 '18 at 21:52

4

You don't have to manually disconnect() signals and slots, the QObject destruction cleans them up automatically.

edited Sep 08 '18 at 21:52

AAEM

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answered Feb 13 '12 at 17:17

Frank Osterfeld

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Qt Signals and Slots object disconnect?

2 Answers2

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