bsd man page for getprotobynumber

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  getpro-
       tobyname or getprotobynumber.

       Endprotoent closes the file.

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

4.2 Berkeley Distribution					   May 19, 1986 						   GETPROTOENT(3N)