DPMSForceLevel - forces a DPMS capable display into the specified power level
cc [ flag ... ] file ... -lXext [ library ... ]
#include <X11/extensions/dpms.h>
Status DPMSForceLevel ( Display *display, CARD16 level );
  - display
- Specifies the connection to the X server
- level
- Specifies the level to force power to
The DPMSForceLevel function forces a DPMS capable display into the
  specified power level. The level must be one of following four states:
  DPMSModeOn, DPMSModeStandby, DPMSModeSuspend, or DPMSModeOff. Values other
  than these will result in a BadValue error. If DPMS is disabled on the
  display, trying to set the power level on the display will result in a
  BadMatch protocol error.
  - TRUE
- The DPMSForceLevel function always returns TRUE.
  - BadValue
- A level other than DPMSModeOn, DPMSModeStandby, DPMSModeSuspend, or
      DPMSModeOff was specified.
- BadMatch
- DPMS is disabled on the specified display.
DPMSCapable(3), DPMSInfo(3), DPMSGetTimeouts(3),
  DPMSSetTimeouts(3)