\DOC MESG_outstream

\TYPE {MESG_outstream : TextIO.outstream ref}

\SYNOPSIS
Reference to output stream used when printing {HOL_MESG}.

\KEYWORDS
I/O, messages, output

\DESCRIBE
The value of reference cell {MESG_outstream} controls where {HOL_MESG}
prints its argument.

The default value of {MESG_outstream} is {TextIO.stdOut}.

\EXAMPLE
{
- val ostrm = TextIO.openOut "foo";
> val ostrm = <outstream> : outstream

- MESG_outstream := ostrm;
> val it = () : unit

- HOL_MESG "Nattering nabobs of negativity.";
> val it = () : unit

- TextIO.closeOut ostrm;
> val it = () : unit

- val istrm = TextIO.openIn "foo";
> val istrm = <instream> : instream

- print (TextIO.inputAll istrm);
<<HOL message: Nattering nabobs of negativity.>>
}


\SEEALSO
Feedback, Feedback.HOL_MESG, Feedback.ERR_outstream, Feedback.WARNING_outstream, Feedback.emit_MESG.
\ENDDOC