Copyright (C) 1994, Digital Equipment Corp.
Stdio
provides streams for standard input, standard output, and
standard error. These streams correspond to file handles returned
by the GetStandardFileHandles
procedure in the Process
interface.
\index{standard I/O!streams}
INTERFACEThe initialization of these streams depends on the underlying operating system.Stdio ; IMPORT Rd, Wr; VAR stdin: Rd.T; stdout: Wr.T; stderr: Wr.T; bufferedStderr: Wr.T; END Stdio.
If the standard error stream is directed to a terminal, it will be
unbuffered, so that explicit Wr.Flush
calls are unnecessary for
interactive programs. A buffered version of the standard error
stream is also provided, but programs should not use both stderr
and bufferedStderr
.
If the streams are directed to or from random-access files, they will be seekable.
It is possible that stderr
is equal to stdout
. Therefore,
programs that perform seek operations on stdout
should take care
not to destroy output data when writing error messages.