netdb.h(3HEAD) Headers netdb.h(3HEAD)NAME
netdb.h, netdb - definitions for network database operations
SYNOPSIS
#include <netdb.h>
DESCRIPTION
The <netdb.h> header defines the type in_port_t and the type in_addr_t
as described in in.h(3HEAD).
The <netdb.h> header defines the hostent structure that includes the
following members:
char *h_name /* official name of the host */
char **h_aliases /* pointer to an array of pointers to alternative */
/* host names, terminated by a null pointer */
int h_addrtype /* address type */
int h_length /* length, in bytes, of the address */
char **h_addr_list /* pointer to an array of pointers to network addresses */
/* (in network byte order) for the host, terminated by a */
/* null pointer */
The <netdb.h> header defines the netent structure that includes the
following members:
char *n_name /* official, fully-qualified (including the domain) name */
/* of the network */
char **n_aliases /* pointer to an array of pointers to alternative */
/* network names, terminated by a null pointer */
int n_addrtype /* the address type of the network */
in_addr_t n_net /* the network number, in host byte order */
The <netdb.h> header defines the protoent structure that includes the
following members:
char *p_name /* official name of the protocol */
char **p_aliases /* pointer to an array of pointers to alternative */
/* protocol names, terminated by a null pointer */
int p_proto /* protocol number */
The <netdb.h> header defines the servent structure that includes the
following members:
char *s_name /* fficial name of the service */
char **s_aliases /* pointer to an array of pointers to alternative */
/* service names, terminated by a null pointer */
int s_port /* port number at which the service resides, */
/* in network byte order */
char *s_proto /* name of the protocol to use when */
/* contacting the service */
The <netdb.h> header defines the macro IPPORT_RESERVED with the value
of the highest reserved Internet port number.
The <netdb.h> header provides a declaration for h_errno:
extern int h_errno;
The <netdb.h> header defines the following macros for use as error val‐
ues for gethostbyaddr() and gethostbyname():
HOST_NOT_FOUND NO_DATA
NO_RECOVERY TRY_AGAIN
Inclusion of the <netdb.h> header may also make visible all symbols
from in.h(3HEAD).
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOintro(3), endhostent(3NSL), endhostent(3XNET), endnetent(3SOCKET), end‐
netent(3XNET), endprotoent(3SOCKET), endprotoent(3XNET), endser‐
vent(3SOCKET), endservent(3XNET), in.h(3HEAD), attributes(5), stan‐
dards(5)SunOS 5.10 10 Sep 2004 netdb.h(3HEAD)
