getservbyport(3) -- Linux man page
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 port port 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 servent structure, or a NULL pointer if an
error occurs or the end of the file is reached.
FILES
- /etc/services
-
services database file
CONFORMING TO
BSD 4.3
SEE ALSO
getprotoent(3),
getnetent(3),
services(5)
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