flush_output/[0,1]
[ISO]flush_output
flush_output(
+Stream)
Forces the buffered output of the stream Stream (defaults to the current output stream) to be sent to the associated device.
A valid Prolog stream, defaults to the current output stream.
Sends the current buffered output of an output stream Stream to the actual output device, which is usually a disk or a tty device.
Stream errors (see ref-iou-sfh-est), plus:
permission_error