2.2.3.4 DOMAIN_SERVER_ROLE

The DOMAIN_SERVER_ROLE enumeration indicates whether a server is a PDC.

 typedef  enum _DOMAIN_SERVER_ROLE
 {
   DomainServerRoleBackup = 2,
   DomainServerRolePrimary = 3
 } DOMAIN_SERVER_ROLE,
  *PDOMAIN_SERVER_ROLE;

DomainServerRoleBackup:  The DC is not the PDC.

DomainServerRolePrimary:  The DC is the PDC.