B4X

Bind and Listen on an Available Port in a Range

Demonstrates Socket.BindAndListenPortRange, which searches an inclusive port range for an available TCP port, binds it, and begins listening. It returns the selected port, or -1 on failure.

Background. This is useful when any of several ports is acceptable and the application needs to discover which one was bound.

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Dim socket As ChilkatSocket
socket.Initialize("socket")

'  Search the inclusive port range for an available TCP port, bind it, and begin listening.  The
'  method returns the selected port, or -1 when no port can be bound.
Dim boundPort As Int = socket.BindAndListenPortRange(5000, 5100, 25)
If boundPort < 0 Then
    Log(socket.LastErrorText)
    Return
End If

Log("Listening on port " & boundPort)