A .prn file is just a dump of what is sent to the printer when we ask the computer to print, so i think there should be some win32API functions to do that. i know how to print a *.prn file, just use these printer spooler function as follows:
openprinter
startdocprinter
StartPagePrinter
writeprinter
EndPagePrinter
EndDocPrinter
ClosePrinter

the problem is how i can make a standard *.prn file with win32 API and save to disk, so i can call a general procedure to print it at appropriate time?