#define mpiEventMaskCOMPLEMENT(mask)((mask)[0] = ~(mask)[0]), 
                            \ ((mask)[1] = ~(mask)[1])

EventMaskCOMPLEMENT() changes the value of every bit within the event mask. If the mask is origininally set to handle an event, then mask will be set to not handle the event after the call to mpiEventMaskCOMPLEMENT(). Likewise, If the mask is origininally set to not handle an event, then mask will be set to handle the event after the call to mpiEventMaskCOMPLEMENT().