TIP #337 IMPLEMENTATION

        * doc/BackgdErr.3:      Converted internal routine
        * doc/interp.n:         TclBackgroundException() into public routine
        * generic/tcl.decls:    Tcl_BackgroundException().
        * generic/tclEvent.c:
        * generic/tclInt.decls:

        * generic/tclDecls.h:   make genstubs
        * generic/tclIntDecls.h:
        * generic/tclStubInit.c:

        * generic/tclIO.c:      Update callers.
        * generic/tclIOCmd.c:
        * generic/tclInterp.c:
        * generic/tclTimer.c:
        *** POTENTIAL INCOMPATIBILITY only for extensions using the converted
        internal routine ***

1 files changed, 34 insertions, 17 deletions

diff --git a/doc/BackgdErr.3 b/doc/BackgdErr.3
index 3309d25..ba53dc6 100644
--- a/doc/BackgdErr.3
+++ b/doc/BackgdErr.3
@@ -5,59 +5,76 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: BackgdErr.3,v 1.8 2007/12/13 15:22:30 dgp Exp $
+'\" RCS: @(#) $Id: BackgdErr.3,v 1.9 2008/12/09 20:16:29 dgp Exp $
 '\" 
 .so man.macros
 .TH Tcl_BackgroundError 3 7.5 Tcl "Tcl Library Procedures"
 .BS
 .SH NAME
-Tcl_BackgroundError \- report Tcl error that occurred in background processing
+Tcl_BackgroundException, Tcl_BackgroundError \- report Tcl exception that occurred in background processing
 .SH SYNOPSIS
 .nf
 \fB#include <tcl.h>\fR
 .sp
+\fBTcl_BackgroundException\fR(\fIinterp, code\fR)
+.sp
 \fBTcl_BackgroundError\fR(\fIinterp\fR)
 .SH ARGUMENTS
 .AS Tcl_Interp *interp
 .AP Tcl_Interp *interp in
-Interpreter in which the error occurred.
+Interpreter in which the exception occurred.
+.AP int code in
+The exceptional return code to be reported.
 .BE
 
 .SH DESCRIPTION
 .PP
-This procedure is typically invoked when a Tcl error occurs during
+This procedure is typically invoked when a Tcl exception (any
+return code other than TCL_OK) occurs during
 .QW "background processing"
 such as executing an event handler.
-When such an error occurs, the error condition is reported to Tcl
+When such an exception occurs, the condition is reported to Tcl
 or to a widget or some other C code, and there is not usually any
-obvious way for that code to report the error to the user.
-In these cases the code calls \fBTcl_BackgroundError\fR with an
+obvious way for that code to report the exception to the user.
+In these cases the code calls \fBTcl_BackgroundException\fR with an
 \fIinterp\fR argument identifying the interpreter in which the
-error occurred.  At the time \fBTcl_BackgroundError\fR is invoked,
-the interpreter's result is expected to contain an error message.
-\fBTcl_BackgroundError\fR will invoke the command registered
+exception occurred, and a \fIcode\fR argument holding the return
+code value of the exception.  The state of the interpreter, including
+any error message in the interpreter result, and the values of
+any entries in the return options dictionary, is captured and
+saved.  \fBTcl_BackgroundException\fR then arranges for the event
+loop to invoke at some later time the command registered
 in that interpreter to handle background errors by the
-\fBinterp bgerror\fR command.
-The registered handler command is meant to report the error
+\fBinterp bgerror\fR command, passing the captured values as
+arguments.
+The registered handler command is meant to report the exception
 in an application-specific fashion.  The handler command
 receives two arguments, the result of the interp, and the
 return options of the interp at the time the error occurred.
 If the application registers no handler command, the default
 handler command will attempt to call \fBbgerror\fR to report
 the error.  If an error condition arises while invoking the
-handler command, then \fBTcl_BackgroundError\fR reports the
+handler command, then \fBTcl_BackgroundException\fR reports the
 error itself by printing a message on the standard error file.
 .PP
-\fBTcl_BackgroundError\fR does not invoke the handler command immediately
+\fBTcl_BackgroundException\fR does not invoke the handler command immediately
 because this could potentially interfere with scripts that are in process
 at the time the error occurred.
 Instead, it invokes the handler command later as an idle callback.
 .PP
-It is possible for many background errors to accumulate before
-the handler command is invoked.  When this happens, each of the errors
-is processed in order.  However, if the handle command returns a
+It is possible for many background exceptions to accumulate before
+the handler command is invoked.  When this happens, each of the exceptions
+is processed in order.  However, if the handler command returns a
 break exception, then all remaining error reports for the
 interpreter are skipped.
+.PP
+The \fBTcl_BackgroundError\fR routine is an older and simpler interface
+useful when the exception code reported is \fBTCL_ERROR\fR.  It is
+equivalent to:
+.PP
+.CS
+Tcl_BackgroundException(interp, TCL_ERROR);
+.CE
 
 .SH KEYWORDS
 background, bgerror, error, interp