Does bytesAvailable() decrease when read() is called?

Upon QIODevice::readyRead() signal, suppose bytesAvailable() returns 50, and say that I read(40).

If I call bytesAvailable() again, would it return 50, or 10?

Thanks.

It depends whether the device is sequential (10) or random access (0). Assuming the method returns 50 in the first place, the device is sequential, so it will return 10 or more (in case more data arrives in the meantime).

Thank you for the detailed answer. Yes, in my original, I meant it was sequential (socket), but you pointed out. Thanks! :)