Best approach to obtain the port of a QTcpServer in a child process?

Asked Nov 21 '12 at 22:52

Active Dec 22 '12 at 11:50

Viewed 231 times

What is the best approach to retrieve the port number a QTcpServer in a child process is listening on, assuming we do not want to use fixed port numbers for our TCP servers? So far I have been experimenting with the following two approaches:

Start a QTcpServer in the main process and send the port of the TCP server in the child process to the TCP server of the parent process. This works but is cumbersome.
Print the port number of the QTcpServer in the child process to stdout and read the standard output from the child process to obtain the port number in the parent process.

Is there another obvious and clean solution that I'm overlooking?

edited Dec 22 '12 at 11:50

asked Nov 21 '12 at 22:52

Ton van den Heuvel

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Does your child process have any kind of conifg file? Where does it take port from? – Kamil Klimek Nov 22 '12 at 09:25
The port is randomly selected by `QTcpServer`, by letting it listen on port 0. The advantage is that it will always listen on an available port. – Ton van den Heuvel Nov 22 '12 at 14:48
maybe use shared memory? – Kamil Klimek Nov 22 '12 at 15:42
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This is rather unconventional, you'd expect the parent process to create the server and when creating the child, the port is already available to the child (assuming you do a fork() in a Unix process). – Alexis Wilke Dec 19 '12 at 12:34

Best approach to obtain the port of a QTcpServer in a child process?

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