VMS Help TCPIP Services, Programming Interfaces, Sockets API, getprotobynumber()  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Searches the protocols database until a matching protocol number
    is found or until end of file is encountered.
    Format
      #include  <netdb.h>
      struct protoent *getprotobynumber  ( int *proto) ;

  Additional Information (explode) :

• Argument
• Description
• Return Values