getservent(SLIB)

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

Syntax

cc ... -lsocket

#include  <netdb.h>

struct servent *
getservent ( )

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

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

int
setservent (stayopen)
int stayopen;

int
endservent ( )

Description

getservent, getservbyname, and getservbyport each returns 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:

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

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

setservent opens and rewinds the file. If the stayopen flag is non-zero, the network 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 EOF is encountered. If a protocol name is also supplied (non-NULL), searches must also match the protocol.

Files

/etc/services

Diagnostics

A null pointer (0) is returned on EOF or error. This does not apply to endservent or getservent.

Limitations