Tcl_BackgroundError - report Tcl error that occurred in
Tcl_Interp *interp (in) Interpreter in which the
This procedure is typically invoked when a Tcl error
occurs during ``background processing'' such as executing
an event handler. When such an error occurs, the error
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 Tcl_BackgroundError with an interp argument
identifying the interpreter in which the error occurred.
At the time Tcl_BackgroundError is invoked, the inter
preter's result is expected to contain an error message.
Tcl_BackgroundError will invoke the bgerror Tcl command to
report the error in an application-specific fashion. If
no bgerror command exists, or if it returns with an error
condition, then Tcl_BackgroundError reports the error
itself by printing a message on the standard error file.
Tcl_BackgroundError does not invoke bgerror immediately
because this could potentially interfere with scripts that
are in process at the time the error occurred. Instead,
it invokes bgerror later as an idle callback. Tcl_Back
groundError saves the values of the errorInfo and error
Code variables and restores these values just before
It is possible for many background errors to accumulate
before bgerror is invoked. When this happens, each of the
errors is processed in order. However, if bgerror returns
a break exception, then all remaining error reports for
the interpreter are skipped.
background, bgerror, error