qint64 QIODevice::bytesAvailable () const [virtual]
Returns the number of bytes that are available for reading. This function is commonly used with sequential devices to determine the number of bytes to allocate in a buffer before reading.
Subclasses that reimplement this function must call the base implementation in order to include the size of QIODevices' buffer. Example:
qint64 CustomDevice::bytesAvailable() const
return buffer.size() + QIODevice::bytesAvailable();
void QIODevice::readyRead () [signal]
This signal is emitted once every time new data is available for reading from the device. It will only be emitted again once new data is available, such as when a new payload of network data has arrived on your network socket, or when a new block of data has been appended to your device.
readyRead() is not emitted recursively; if you reenter the event loop or call waitForReadyRead() inside a slot connected to the readyRead() signal, the signal will not be reemitted (although waitForReadyRead() may still return true).
Note for developers implementing classes derived from QIODevice: you should always emit readyRead() when new data has arrived (do not emit it only because there's data still to be read in your buffers). Do not emit readyRead() in other conditions.