'\" '\" Copyright (c) 1990-1992 The Regents of the University of California. '\" Copyright (c) 1994-1995 Sun Microsystems, Inc. '\" Copyright (c) 1996-1999 Christian Werner '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" .so man.macros .TH update n 8.0 Ck "Ck Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME update \- Process pending events and/or when-idle handlers .SH SYNOPSIS \fBupdate\fR ?\fBidletasks|screen\fR? .BE .SH DESCRIPTION .PP This command is used to bring the entire application world ``up to date.'' It flushes all pending output to the display, waits for the server to process that output and return errors or events, handles all pending events of any sort (including when-idle handlers), and repeats this set of operations until there are no pending events, no pending when-idle handlers, no pending output to the server, and no operations still outstanding at the server. .PP If the \fBidletasks\fR keyword is specified as an argument to the command, then no new events or errors are processed; only when-idle idlers are invoked. This causes operations that are normally deferred, such as display updates and window layout calculations, to be performed immediately. .PP The \fBupdate idletasks\fR command is useful in scripts where changes have been made to the application's state and you want those changes to appear on the display immediately, rather than waiting for the script to complete. Most display updates are performed as idle handlers, so \fBupdate idletasks\fR will cause them to run. However, there are some kinds of updates that only happen in response to events, such as those triggered by window size changes; these updates will not occur in \fBupdate idletasks\fR. .PP If the \fBscreen\fR keyword is specified as an argument to the command, then the entire screen is repainted from scratch without handling any other events. This is useful if the terminal's screen has been garbled by another process. .PP The \fBupdate\fR command with no options is useful in scripts where you are performing a long-running computation but you still want the application to respond to user interactions; if you occasionally call \fBupdate\fR then user input will be processed during the next call to \fBupdate\fR. .SH KEYWORDS event, flush, handler, idle, update