Thanks, Bart. That makes sense. Once again, I really appreciate your time and help. Joe -----Original Message----- From: Bart Trojanowski [mailto:bart-oclug [ at ] jukie [ dot ] net] Sent: Tuesday, November 04, 2008 10:57 AM To: linux [ at ] lists [ dot ] oclug [ dot ] on [ dot ] ca Cc: Zhao, Joe Subject: Re: [OCLUG-Tech] device driver magic number for ioctl() in linux One more time... > > #define _IOC(dir,type,nr,size) \ > > (((0) << 22) | \ For some reason I can neither add at 2am or before my 2nd cup of coffee. 16+14 is... (((dir) << 30) | \ > > ((size) << 16) | \ > > ((type) << 8) | \ > > ((nr) << 0)) -Bart -- WebSig: http://www.jukie.net/~bart/sig/