in(5)

NAME

in − Internet Protocol family

SYNOPSIS

#include <netinet/in.h>

DESCRIPTION

The <netinet/in.h> header defines the following types through typedef:

in_port_t An unsigned integral type of exactly 16 bits.

in_addr_t An unsigned integral type of exactly 32 bits.

The <netinet/in.h> header defines the in_addr structure that includes the following member:

in_addr_t

s_addr

The <netinet/in.h> header defines the type sa_family_t as described in socket(5).

The <netinet/in.h> header defines the following macros for use as values of the level argument of getsockopt() and setsockopt():

IPPROTO_IP Dummy for IP

IPPROTO_ICMP Control message protocol

IPPROTO_TCP TCP

IPPROTO_UDP User datagram protocol

The <netinet/in.h> header defines the following macros for use as destination addresses for connect(), sendmsg(), and sendto():

INADDR_ANY Local host address

INADDR_BROADCAST Broadcast address

Default

For applications that do not require standard-conforming behavior (those that use the socket interfaces described in section 3N of the reference manual; see Intro(3) and standards(5)), the <netinet/in.h> header defines the sockaddr_in structure that includes the following members:

sa_family_t	sin_family
in_port_t	sin_port
struct in_addr	sin_addr
char	sin_zero[8]

Standard-conforming

For applications that require standard-conforming behavior (those that use the socket interfaces described in section 3XN of the reference manual; see Intro(3) and standards(5)), the <netinet/in.h> header defines the sockaddr_in structure that includes the following members:

sa_family_t	sin_family
in_port_t	sin_port
struct in_addr	sin_addr
unsigned char	sin_zero[8]

The sockaddr_in structure is used to store addresses for the Internet protocol family. Values of this type must be cast to struct sockaddr for use with the socket interfaces.

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