ERR_outstream

Feedback.ERR_outstream : TextIO.outstream ref

Reference to output stream used when printing HOL_ERR

The value of reference cell ERR_outstream controls where Raise prints its argument.

The default value of ERR_outstream is TextIO.stdErr.

Example

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

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

- Raise (mk_HOL_ERR "Foo" "bar" "incomprehensible input");
! Uncaught exception:
! HOL_ERR

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

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

- print (TextIO.inputAll istrm);

Exception raised at Foo.bar:
incomprehensible input

See also

Feedback, Feedback.HOL_ERR, Feedback.Raise, Feedback.MESG_outstream, Feedback.WARNING_outstream