---
name: "sockaddr_in"
section: "3type"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/sockaddr_in"
---

# sockaddr\_in(3type)

IPv4 socket address

## NAME

sockaddr\_in, in\_addr, in\_addr\_t, in\_port\_t - IPv4 socket address

## LIBRARY

Standard C library (*libc*)

## SYNOPSIS

```
#include <netinet/in.h>
```

**struct sockaddr\_in {**     **sa\_family\_t     sin\_family;**     /\* **AF\_INET** \*/     **in\_port\_t       sin\_port;**       /\* Port number \*/     **struct in\_addr  sin\_addr;**       /\* IPv4 address \*/ **};**

**struct in\_addr {**     **in\_addr\_t s\_addr;** **};**

**typedef uint32\_t in\_addr\_t;** **typedef uint16\_t in\_port\_t;**

## DESCRIPTION

- *sockaddr\_in*

  Describes an IPv4 Internet domain socket address.

-

  *.sin\_port* and *.sin\_addr* are stored in network byte order.

## STANDARDS

POSIX.1-2024.

## HISTORY

POSIX.1-2001.

## SEE ALSO

[**sockaddr**(3type)](/sockaddr/3type.md), [**sockaddr\_in6**(3type)](/sockaddr_in6/3type.md)