getprotoent() -- Sockets Function (libsocket)

Get protocol entry
#include <netdb.h>
struct protoent *getprotoent();

getprotoent() reads  the next entry  from file /etc/protocols,  which holds
information  about all  protocols  recognized by  your  local network.   If
necessary, it  opens the file.  It  returns a pointer to  an object of type
protoent, which is defined in header file <netdb.h>:

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

The following details each member:

p_name
     The official name of the protocol.

p_aliases
     This  points to  a  zero-terminated list  of alternate  names for  the
     protocol.

p_proto
     The number of the protocol.

To close /etc/protocols, call function endprotoent().

getprotoent() returns NULL if an error  occurs, or if it encounters the end
of the file.

See Also

endprotoent(),
getprotobyname(),
getprotobynumber(),
libsocket,
netdb.h,
setprotoent()

Notes

This function uses a static data  space.  If your application needs to save
these data, it must copy them before any subsequent calls overwrite them.

At present, only the Internet protocols are understood.

© 2012 by Stephen A. Ness