XSGIvcSetOutputBlanking(3)

     NAME
          XSGIvcSetOutputBlanking, XSGIvcQueryOutputBlanking - Channel
          Blanking Operations

     SYNOPSIS
          #include <X11/extensions/XSGIvc.h>

          void XSGIvcSetOutputBlanking(Display *display,
              int screen,
              int channel,
              Bool enable)

          Status XSGIvcQueryOutputBlanking(Display *display,
              int screen,
              int channel,
              Bool *enableReturn)

     PARAMETERS
          display        Specifies the connection to the X server.

          screen         Specifies the screen of the X server.

          channel        Specifies the channel number.

          enable         Specifies whether blanking should be enabled.

          enableReturn   Returns whether blanking is enabled.


     DESCRIPTION
          Simple screen savers use this function to force the screen
          to black.

          When a channel is blanked, the active video portion of the
          signal is disabled.  The screen is drawn black; however,
          normal video synchronization signals persist so the monitor
          can remain locked.  When blanking is disabled, the active
          video is restored and the monitor once again displays
          pictures.

          XSGIvcSetOutputBlanking enables and disables blanking on a
          channel. The value may be True or False.

          XSGIvcQueryOutputBlanking returns the current settings for
          blanking on a channel.  The value may be True or False.


        Interaction with Screen Saver
          Some screen saver programs will simply blank the screen as
          part or all of their function; the screen saver is
          controlled by XSetScreenSaver, et al.  The function of
          OutputBlanking is independent of that supplied by that of
          the screen saver, which uses a different mechanism to enable
          and disable output. A channel will display only if the
          screen saver is not active and blanking is not enabled; that
          is, either one of the screen saver or blanking will disable
          output to a channel.



     EVENTS
          When this control is altered, the server generates a
          OutputBlankingNotify event.


     RETURNED VALUE
          XSGIvcQueryOutputBlanking returns TRUE if successful, FALSE
          upon failure.

          Parameter errors are reported via BadValue or BadMatch.


     SEE ALSO
          XSGIvc, XSetScreenSaver