NAME
getprotoent,
getprotoent_r,
getprotobynumber,
getprotobynumber_r,
getprotobyname,
getprotobyname_r,
setprotoent, setprotoent_r,
endprotoent, endprotoent_r
— get protocol entry
SYNOPSIS
#include
<netdb.h>
struct protoent *
getprotoent(void);
int
getprotoent_r(struct
protoent *protoent,
struct protoent_data
*protoent_data);
struct protoent *
getprotobyname(const
char *name);
int
getprotobyname_r(const
char *name, struct
protoent *protoent,
struct protoent_data
*protoent_data);
struct protoent *
getprotobynumber(int
proto);
int
getprotobynumber_r(int
proto, struct protoent
*protoent, struct
protoent_data *protoent_data);
void
setprotoent(int
stayopen);
void
setprotoent_r(int
stayopen, struct
protoent_data *protoent_data);
void
endprotoent(void);
void
endprotoent_r(struct
protoent_data *protoent_data);
DESCRIPTION
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 database,
/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 null-terminated list of alternate 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 protocol database will not be closed after each call
to getprotobyname() or
getprotobynumber().
The
endprotoent()
function closes the file.
The
getprotobyname()
and
getprotobynumber()
functions sequentially search from the beginning of the file until a
matching protocol name or protocol number is found, or until
EOF is encountered.
The
getprotoent_r(),
getprotobyport_r(),
getprotobyname_r(),
setprotoent_r(),
and
endprotoent_r()
functions are reentrant versions of the above functions that take a pointer
to a protoent_data structure which is used to store
state information. The structure must be zero-filled before it is used and
should be considered opaque for the sake of portability.
The
getprotoent_r(),
getprotobyport_r(),
and
getprotobyname_r()
functions also take a pointer to a protoent structure
which is used to store the results of the database lookup.
RETURN VALUES
The getprotoent(),
getprotobyport(), and
getprotobyname() functions return a pointer to a
protoent structure on success or a null pointer if
end-of-file is reached or an error occurs.
The getprotoent_r(),
getprotobyport_r(), and
getprotobyname_r() functions return 0 on success or
-1 if end-of-file is reached or an error occurs.
FILES
- /etc/protocols
SEE ALSO
STANDARDS
The getprotoent(),
getprotobynumber(),
getprotobyname(),
setprotoent(), and
endprotoent() functions conform to
IEEE Std 1003.1-2004 (“POSIX.1”).
The getprotoent_r(),
getprotobyport_r(),
getprotobyname_r(),
setprotoent_r(), and
endprotoent_r() functions are not currently
standardized. This implementation follows the API used by HP, IBM, and
Digital.
HISTORY
The getprotoent(),
getprotobynumber(),
getprotobyname(),
setprotoent(), and
endprotoent() functions appeared in
4.2BSD.
The getprotoent_r(),
getprotobyport_r(),
getprotobyname_r(),
setprotoent_r(), and
endprotoent_r() functions appeared in
OpenBSD 3.7.
BUGS
The non-reentrant functions use a static data space; if the data is needed for future use, it should be copied before any subsequent calls overwrite it. Only the Internet protocols are currently understood.