long mpiFilterStatus(MPIFilter  filter,
                     MPIStatus  *status,
                     void       *external)

FilterStatus writes a Filter's (filter) status into the structure pointed to by status, and also into the implementation-specific structure pointed to by external (if external is not NULL).

The Filter's status information in external is in addition to the Filter's status information in status, i.e, the status configuration information in status and in external is not the same information. Note that status or external can be NULL (but not both NULL).

external either points to a structure of type MEIFilterStatus{} or is NULL.