The
getprotoent(),
getprotobyname(), and
getprotobynumber() functions 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 alternative names for the protocol.
p_proto
The protocol number.
The
getprotoent() function reads the next line of the file, opening the file if necessary.
The
setprotoent() function 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().
The
endprotoent() function closes the file.
The
getprotobyname() function 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.