Shell Alternative

 BBS: Inland Empire Archive
Date: 03-08-92 (01:52)             Number: 151
From: RICH GELDREICH               Refer#: NONE
  To: TIM FITZGERALD                Recvd: NO  
Subj: Shell Alternative              Conf: (11) Quik_Bas

Well... this is about preventing the user from seeing anything that a SHELL'd program writes to the screen. I have two ways(off the top of my head)- one of 'em might not work. The first method, which probably won't work, is to keep your display and work screens seperate. For instance: Screen 0,,1,0 'sets up text mode with work page of 1 and display of 0 Then, shell to your program. This *may* make dos write everything to page 1 while the user only sees page 0, but I haven't tested this out so you will have to experiment with that. The second way is to set all of the palette attributes to black, shell to dos, and then set the palette back to normal. Setting all of the screen attributes to 0 will effectively turn off the display so anything written to it will not be seen. Like this: pcopy 0,1 'save your clean text screen to a temperary page for A=0 to 255:palette A,0:next 'this will work with VGA shell "myprog" pcopy 1,0 palette 'set palette back to normal The first pcopy 0,1 copies the normal display page to a temperary place so it can be restored later. Next, all of the atttributes to the screen are set to 0. The program is executed, effectively invisible to the user. Then, the original screen is copied back and the palettes are set back to normal. Hope that helps! Rich Geldreich --- RBBSMAIL 17.2A * Origin: Computer Co-Op RBBS HST, 609-784-9404 Voorhees NJ (RBBS-PC 1:266/29)
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