'\"
'\" Copyright (c) 1993 The Regents of the University of California.
'\" Copyright (c) 1994-1997 Sun Microsystems, Inc.
'\" Copyright (c) 1993-1997 Bell Labs Innovations for Lucent Technologies
'\" Copyright (c) 1998-2000 Ajuba Solutions
'\" Copyright (c) 2007-2008 Donal K. Fellows
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" RCS: @(#) $Id: info.n,v 1.39 2010/10/17 20:16:55 ferrieux Exp $
'\" RCS: @(#) $Id: info.n,v 1.40 2010/10/20 20:52:26 ferrieux Exp $
'\" 
.so man.macros
.TH info n 8.4 Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
info \- Return information about the state of the Tcl interpreter

.TP
\fBinfo errorstack \fR?\fIinterp\fR?
.VS 8.6
Returns, in a form that is programmatically easy to parse, the function names
and arguments at each level from the call stack of the last error in the given
\fIinterp\fR, or in the current one if not specified.

This form is an
even-sized list alternating tokens and parameters. Tokens are currently either
\fBCALL\fR or \fBUP\fR, but other values may be introduced in the
future. \fBCALL\fR indicates a procedure call, and its parameter is the
corresponding [info level 0]; \fBUP\fR indicates a shift in variable frames
generated by uplevel or similar, and applies to the previous CALL item. Its
parameter is the level offset.
This form is an even-sized list alternating tokens and parameters. Tokens are
currently either \fBCALL\fR, \fBUP\fR, or \fBINNER\fR, but other values may be
introduced in the future. \fBCALL\fR indicates a procedure call, and its
parameter is the corresponding [info level 0]. \fBUP\fR indicates a shift in
variable frames generated by uplevel or similar, and applies to the previous
CALL item. Its parameter is the level offset. \fBINNER\fR identifies the
"inner context", which is the innermost atomic command or bytecode instruction
that raised the error, along with its arguments when available. While
\fBCALL\fR and \fBUP\fR allow to follow complex call paths, \fBINNER\fR homes
in on the offending operation in the innermost proc call, even going to
sub-expr granularity.

This information is also present in the
\fB\-errorstack\fR entry of the options dictionary returned by 3-argument
\fBcatch\fR; \fBinfo errorstack\fR is a convenient way of retrieving it for
uncaught errors at toplevel in an interactive tclsh.
.VE 8.6
.TP