COHERENT manpages
This page displays the COHERENT manpage for getprotobynumber() [Get protocol entry by protocol number].
List of available manpages
Index
getprotobynumber() -- Sockets Function (libsocket) Get protocol entry by protocol number #include <netdb.h> struct protoent *getprotobynumber(protocol); int protocol; getprotobynumber() searches file /etc/protocols, which holds information about all protocols recognized by your local network, for the protocol identified by number. /etc/protocols has to have been opened by a call to setprotoent(). getprotobynumber() 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. getprotobynumber() returns NULL if an error occurs, or if it encounters the end of the file. See Also endprotoent(), getprotobyname(), getprotoent(), 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.