Linux / Unix Command: getservbyname

http://linux.about.com/library/cmd/blcmdl3_getservbyname.htm

NAME

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

SYNOPSIS

#include <netdb.h>

struct servent *getservent(void);

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

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

void setservent(int stayopen);

void endservent(void);

 

DESCRIPTION

The getservent() function
reads the next line from the file /etc/services and returns a
structure servent containing the broken out fields from the line.
The /etc/services file is opened if necessary.

The getservbyname() function returns a servent structure for the line from /etc/services that matches the service name using protocol proto. If proto is NULL, any protocol will be matched.

The getservbyport() function returns a servent structure for the line that matches the portport given in network byte order using protocol proto. If proto is NULL, any protocol will be matched.

The setservent() function opens and rewinds the /etc/services file. If stayopen is true (1), then the file will not be closed between calls to getservbyname() and getservbyport().

The endservent() function closes /etc/services.

The servent structure is defined in <netdb.h> as
follows:

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

The members of the servent structure are:

s_name
The official name of the service.
s_aliases
A zero terminated list of alternative names for the service.
s_port
The port number for the service given in network byte order.
s_proto
The name of the protocol to use with this service. 

RETURN VALUE

The getservent(), getservbyname() and getservbyport() functions
return the serventstructure, or a NULL pointer if an error occurs
or the end of the file is reached.  

SEE ALSO

getprotoent(3), getnetent(3), services(5)