Availability:built-in
stdin
. Out
becomes
stdout
. If Error equals Out an
unbuffered stream is associated to the same destination and linked to stderr
.
Otherwise Error is used for stderr
. Output
buffering for
Out is set to line and buffering on Error is
disabled. The operating system I/O streams are shared across all
threads. The three streams must be related to a file descriptor
or a
domain_error
file_stream
is raised. See also
stream_property/2,
property file_no(Fd)
.
Where set_prolog_IO/3
rebinds the Prolog streams user_input
,
user_output
and user_error
for a specific
thread providing a private interactive session, set_system_IO/3
rebinds the shared console I/O and also captures Prolog kernel events
(e.g., low-level debug messages, unexpected events) as well as messages
from foreign libraries that are directly written to stdout
or
stderr
.
This predicate is intended to capture all output in situations where standard I/O is normally lost, such as when Prolog is running as a service on Windows.