DPMSQueryExtension - queries the X server to determine the availability of the DPMS Extension

display
              Specifies the connection to the X server

       event_base
              Specifies the return location for the assigned base event

       error_base
              Specifies the return location for the assigned base error

       The  DPMSQueryExtension  function queries the X server to determine the availability of the Display Power
       Management Signaling (DPMS) Extension.   If  the  extension  is  available,  it  returns  TRUE,  and  the
       event_base  and  error_base  are  set  to the base event and error numbers, respectively.  Otherwise, the
       return value is FALSE, and the values of event_base and error_base are undefined.

       DPMSQueryExtension - queries the X server to determine the availability of the DPMS Extension

       TRUE           The DPMSQueryExtension function returns TRUE if the extension is available, and event_base
                      and error_base are set to the base event number and base error number for  the  extension,
                      respectively.

       FALSE          The  DPMSQueryExtension  function  returns  FALSE  if  extension is not available, and the
                      values of event_base and error_base are undefined.

DPMSGetVersion(3)

X Version 11                                      libXext 1.3.4                            DPMSQueryExtension(3)

cc [ flag ... ] file ... -lXext [ library ... ]
       #include <X11/extensions/dpms.h>

       BoolDPMSQueryExtension
              (
                    Display *display,
                    int *event_base,
                    int *error_base
              );