---
name: "dns_ip4_qualify"
section: "3"
platform: "linux"
package: "libowfat-dev"
version: "0.32-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/dns_ip4_qualify"
---

# dns\_ip4\_qualify(3)

qualify name and look up IPv4 addresses

## NAME

dns\_ip4\_qualify - qualify name and look up IPv4 addresses

## SYNTAX

**#include \<libowfat/dns.h\>**

int **dns\_ip4\_qualify**(stralloc\* *out*,stralloc\* *fqdn*,\
                     const stralloc\* *udn*);

## DESCRIPTION

dns\_ip4\_qualify feeds the name *udn* through qualification and looks up 4-byte IP addresses for the result. It puts the fully qualified domain name into *fqdn*, puts the concatenation of the IP addresses into *out*, and returns 0. If the domain does not exist in DNS, or has no IP addresses, *out* will be empty.

If dns\_ip4\_qualify has trouble with the qualification, has trouble with DNS, or runs out of memory, it returns -1, setting errno appropriately. It may or may not change *out* and *fqdn*.

## QUALIFICATION

See http://cr.yp.to/djbdns/qualification.html

## SEE ALSO

[dns\_ip4(3)](/dns_ip4/3.md), [dns\_ip4\_packet(3)](/dns_ip4_packet/3.md), [dns\_ip6\_qualify(3)](/dns_ip6_qualify/3.md)