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Manual page for GETSERVENT(3N)

getservent, getservbyport, getservbyname, setservent, endservent - get service entry


#include <netdb.h>

struct servent *getservent()

struct servent *getservbyname(name, proto) char *name, *proto;

struct servent *getservbyport(port, proto) int port; char *proto;

setservent(stayopen) int stayopen;



getservent, getservbyname, and getservbyport each return a pointer to an object with the following structure containing the broken-out fields of a line in the network services data base, /etc/services.

struct	servent {
	char	*s_name;	/* official name of service */
	char	**s_aliases;	/* alias list */
	int	s_port;		/* port service resides at */
	char	*s_proto;	/* protocol to use */

The members of this structure are:

The official name of the service.
A zero terminated list of alternate names for the service.
The port number at which the service resides. Port numbers are returned in network short byte order.
The name of the protocol to use when contacting the service.

getservent() reads the next line of the file, opening the file if necessary.

getservent() opens and rewinds the file. If the stayopen flag is non-zero, the net data base will not be closed after each call to getservent() (either directly, or indirectly through one of the other ``getserv'' calls).

endservent() closes the file.

getservbyname() and getservbyport() sequentially search from the beginning of the file until a matching protocol name or port number is found, or until end-of-file is encountered. If a protocol name is also supplied (non-NULL), searches must also match the protocol.




getprotoent.3n services.5 ypserv.8


A NULL pointer is returned on end-of-file or error.


All information is contained in a static area so it must be copied if it is to be saved. Expecting port numbers to fit in a 32 bit quantity is probably naive.

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Created by unroff & hp-tools. © by Hans-Peter Bischof. All Rights Reserved (1997).

Last modified 21/April/97