PrSetError
variable. Use this function to let your printing routine know when the user
has aborted a print job.
iErr is any Error Code. The value iPrAbort (128) is typically used to let your printing loop know that the user wants to abort printing.
Notes: C and ASM programmers may prefer to simply store a value in the global
variable PrintErr (at 0x0944).
While monitoring printing progress via a background routine (i.e., when
you store a function address into TPrint.prInfo.pIdleProc), and the user asks to abort printing (by pressing -period or clicking a Cancel button
of your own devising), you should use: