Take the 2-minute tour ×  Wat happens if two applications try to
listen to the same port?  share|improve this question add
comment  2 Answers  up vote 2 down vote accepted  The second one
that binds to the port will get an error saying something else
is already listening on the port.  share|improve this answer
Does the program check for itself if some other program is
listening to the port? –  Wintermute Mar 3 '11 at 20:33 The
operating system does the check. –  carson Mar 3 '11 at 20:41
add comment  Unless they are spawned via tcpmux, the first
application binds to the port and listens for connections to it,
while the second one cannot bind and cannot listen.
share|improve this answer What is it that prevents the
application from binding to the port? –  Wintermute Mar 3 '11 at
20:36 When your application makes the relevant system call to
"grab" the port, the operating system will "inform" it (via a
relevant error code) that it is already taken. –  adamo Mar 3
'11 at 21:17 add comment  Your Answer