CentOS 7.0 - man page for tcl_backgrounderror (centos section 3)
|Linux & Unix Commands - Search Man Pages
Tcl_BackgroundError(3) Tcl Library Procedures Tcl_BackgroundError(3)
Tcl_BackgroundError - report Tcl error that occurred in background processing
Tcl_Interp *interp (in) Interpreter in which the error occurred.
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 interpreter's result is
expected to contain an error message. Tcl_BackgroundError will invoke the command regis-
tered in that interpreter to handle background errors by the interp bgerror command. The
registered handler command is meant to report the error in an application-specific fash-
ion. 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 bgerror to report the
error. If an error condition arises while invoking the handler command, then Tcl_Back-
groundError reports the error itself by printing a message on the standard error file.
Tcl_BackgroundError 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.
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 break exception, then all remaining error reports for the inter-
preter are skipped.
background, bgerror, error, interp
Tcl 7.5 Tcl_BackgroundError(3)
All times are GMT -4. The time now is 08:30 AM.