Ada Programming/Libraries/Ada.Synchronous Task Control.EDF

is a unit of the Predefined Language Environment since Ada 2012.

Specification
Suspend_Until_True_And_Set_Deadline S    Suspension_Object TS      AdaReal_TimeTime_Span AdaSynchronous_Task_ControlEDF

Wikibook

 * Ada Programming/Libraries/Ada
 * Ada Programming/Libraries/Ada.Synchronous_Task_Control