On Thursday, 11/30/2006 at 08:49 EST, Ray Mansell <[EMAIL PROTECTED]> wrote: > Long ago one could indeed use other codes, but this proved to be a > security hole. (One could send non-displayable messages containing > privileged commands to a privileged user such that the next time that > user pressed the ENTER key, the command would be executed. Not that *I* > ever did anything like that, of course... well, except perhaps for pure > research purposes.) The fix for that was to filter only the > highlighting codes. The ESAY program I mentioned a couple of days ago > allows you to generate colourful linemode output, but only under control > of CP, so there are no explicit attribute codes involved.
Just in case anyone cares, the only 3270 order CP allows in linemode I/O is Start Field (0x1D). All others are converted to blanks (tab is converted to 0x6A). And you're right, CP allows you to manipulate only bits 4 & 5 in the attribute byte that follows the SF. (Note: If you set your output to 'invisible' it will still be visible in a console log.) Your program takes advantage of the fact that CP constructs the 3270 datastream at the time the virtual I/O is performed, not when it is displayed, and is what also allows mixed red & black on the same line on the 3215. :-) Alan Altmark z/VM Development IBM Endicott
