GETPROTOENT(3N)                                   GETPROTOENT(3N)



     NAME
          getprotoent, getprotobynumber, getprotobyname, setprotoent,
          endprotoent - get protocol entry

     SYNOPSIS
          #include <netdb.h>

          struct protoent *getprotoent()

          struct protoent *getprotobyname(name)
          char *name;

          struct protoent *getprotobynumber(proto)
          int proto;

          setprotoent(stayopen)
          int stayopen

          endprotoent()

     DESCRIPTION
          Getprotoent, getprotobyname, and getprotobynumber each
          return a pointer to an object with the following structure
          containing the broken-out fields of a line in the network
          protocol data base, /etc/protocols.

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

          The members of this structure are:

          p_name     The official name of the protocol.

          p_aliases  A zero terminated list of alternate names for the
                     protocol.

          p_proto    The protocol number.

          Getprotoent reads the next line of  the  file,  opening  the
          file if necessary.

          Setprotoent opens and rewinds the  file.   If  the  stayopen
          flag is non-zero, the net data base will not be closed after
          each call to getprotobyname or getprotobynumber.

          Endprotoent closes the file.

          Getprotobyname and getprotobynumber sequentially search from
          the  beginning of the file until a matching protocol name or



     Page 1                                        (last mod. 8/20/87)

     GETPROTOENT(3N)                                   GETPROTOENT(3N)



          protocol number is found, or until EOF is encountered.

     FILES
          /etc/protocols

     SEE ALSO
          protocols(5)

     DIAGNOSTICS
          Null pointer (0) returned on EOF or error.

     BUGS
          All information is contained in a static area so it must  be
          copied  if  it  is to be saved.  Only the Internet protocols
          are currently understood.

     NOTE
          There are two versions of the primitives documented in  this
          manual entry:  a vanilla version and a Yellow Pages version.
          The programmatic interface of both  versions  is  identical.
          The  vanilla version gets its information from an ASCII file
          in /etc.  The Yellow Pages version knows about Sun's  Yellow
          Pages  distributed  lookup  service.  If you want the Yellow
          Pages  version,  link   the   program   according   to   the
          instructions  for  (3Y) primitives as described in intro(3).
          Refer to ypserv(1M)  and  the  NFS  User's  Guide  for  more
          information about the Yellow Pages.

     ORIGIN
          4.3 BSD

























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