efn OpenVMS usage:ef_number type: longword (unsigned) access: read only mechanism: by value Number of any event flag in the common cluster to be disassociated. The efn argument is a longword containing this number; however, $DACEFC uses only the low-order byte. The number must be in the range of 64 through 95 for cluster 2, and 96 through 127 for cluster 3.