Multiple Print Screen Calls

Multiple Print Screen calls are ignored while a Print Screen operation is in progress. This prevents multiple screen printouts from being queued if the [PrtSc] key is quickly pressed more than once. The Print Screen service routine updates a status byte at address 40h:100h. The value of this byte is interpreted as follows:

• 00h No Print Screen activity.
• 01h A Print Screen operation is in progress.
• FFh The previous Print Screen operation terminated with an error.