user
or P4 or both.
?- open('/dev/ttyp4', read, P4), wait_for_input([user, P4], Inputs, 0). |
This predicate relies on the select() call on most operating systems.
On Unix this call is implemented for any stream referring to a
file-handle, which implies all OS-based streams: sockets, terminals,
pipes, etc. On non-Unix systems select() is generally only implemented
for socket-based streams. See also library(socket)
from the clib
package.
on
(default) and off
.
First Old is unified with the current value. Then the new
value is set to New. (27)
With the introduction of exception-handling, it is adviced to use
catch/3
to catch possibly file-errors and act accordingly. Note that if fileerrors
is off
, no exception is generated.