---
name: "ares_inet_pton"
section: "3"
platform: "linux"
package: "c-ares"
version: "1.34.9-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/ares_inet_pton"
---

# ares\_inet\_pton(3)

convert an IPv4 or IPv6 address from text to binary form

## NAME

ares\_inet\_pton - convert an IPv4 or IPv6 address from text to binary form

## SYNOPSIS

```
#include <ares.h>
int ares_inet_pton(int af, const char *src, void *dst);
```

## DESCRIPTION

This is a portable version of the commonly available *inet\_pton*.  It behaves the same for AF\_INET6, and for AF\_INET it additionally accepts the legacy forms described below.

The ares\_inet\_pton() function converts the address in its standard text presentation form into its numeric binary form. The **af** argument shall specify the family of the address. The AF\_INET and AF\_INET6 address families shall be supported. The **src** argument points to the string being passed in. The **dst** argument points to a buffer into which the function stores the numeric address; this shall be large enough to hold the numeric address (32 bits for AF\_INET, 128 bits for AF\_INET6).

The **src** argument must be an address, not a network: a "/bits" prefix length suffix (CIDR notation) is not accepted and the function returns 0 for such input.  On success, the whole address (4 bytes for AF\_INET, 16 bytes for AF\_INET6) is always written to **dst**.  Versions of c-ares before 1.34.9 accepted a prefix length here.

Unlike POSIX *inet\_pton*, AF\_INET also accepts shortened forms such as "10.1" and hexadecimal forms such as "0x0a000001".  Octets that are not given are set to zero, so "10.1" is 10.1.0.0.

It returns 1 if the address was valid for the specified address family, or 0 if the address was not parseable in the specified address family, or -1 if the address family is not supported (in which case errno will have been set to EAFNOSUPPORT).

## SEE ALSO

[**ares\_init**(3)](/ares_init/3.md), [**ares\_inet\_ntop**(3)](/ares_inet_ntop/3.md)

## AVAILABILITY

made properly publicly available in c-ares for real in version 1.10.0