This function suspends screen updates for the specified document doc if the flag parameter is zero (0). If the flag parameter is not set, then the function returns the current setting for whether screen updates are suspended for doc (1 if the display is not suspended).

Suspending screen updates may speed up a script that makes many edits to a document that is displayed in a window, especially if partial generated text updates are enabled (the default). Before returning, a script that suspended screen updates would need to re-enable screen updates by calling doc_update_display with the flag parameter set to 1.

Use caution when calling this function. If screen updates are not restored, then the document may be displayed incorrectly to the user.