    NAME
           getprotobyname,  getprotobynumber - get protocol entry

    SYNOPSIS
           #include <network.h>

           struct protoent *getprotobyname(const char *name);

           struct protoent *getprotobynumber(int proto);

    DESCRIPTION
           The getprotobyname() function returns a protoent structure
           for the line from /etc/protocols that matches the protocol
           name name.

           The  getprotobynumber() function returns a protoent struc
           ture for the line that matches the protocol number number.

           The protoent structure is defined in <netdb.h> as follows:

                  struct protoent {
                          char    *p_name;        /* official protocol name */
                          char    **p_aliases;    /* alias list */
                          int     p_proto;        /* protocol number */
                  }

           The members of the protoent structure are:

           p_name The official name of the protocol.

           p_aliases
                  A zero terminated list of alternative names for the
                  protocol.
           p_proto
                  The protocol number.

    RETURN VALUE
           The getprotobyname() and getprotobynumber()
           functions return the protoent structure, or a NULL pointer
           if an error occurs.