cc [ flag ... ] file ... -lXext [ library ... ] #include <X11/extensions/dpms.h>
The DPMSEnable function enables Display Power Management Signaling (DPMS) on the specified display. When DPMS is enabled, DPMS will use the currently saved timeout values. It will trigger the appropriate DPMS power level based on the timeout values. Refer to DPMSSetTimeouts. All physical screens are affected by DPMSEnable at the same time.
If DPMSEnable is invoked on a display which has DPMS already enabled, or on a display which does not support DPMS, no change is made and no error is returned.