NAME

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

SYNOPSIS

#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

endservent()

DESCRIPTION

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.

structservent {
char*s_name;/* official name of service */
char**s_aliases;/* alias list */
ints_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 net data base will not be closed after each call to getservbyname or .IR getservbyport . 

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

SEE ALSO

getprotoent(3N), services(5)

DIAGNOSTICS

Null pointer (0) returned on EOF or error. 

BUGS

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. 

NOTE

There are two versions of the primitives documented in this manual entry:  a vanilla version and a Yellow Pages version.  The programmatic interface of both versions is identical.  The vanilla version gets its information from an ASCII file in /etc. The Yellow Pages version knows about Sun’s Yellow Pages distributed lookup service. If you want the Yellow Pages version, link the program according to the instructions for (3Y) primitives as described in intro(3). Refer to ypserv(1M) and the NFS User’s Guide for more information about the Yellow Pages. 

Version 2.5  —  April 22, 1987