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inet_ntop

Section: C Library Functions (3)
Updated: 202-0-28
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NAME

inet_ntop - convert IPv4 and IPv6 addresses from binary to text form

LIBRARY

Standard C library (libc,~-lc)

SYNOPSIS

#include <arpa/inet.h>
const char *inet_ntop(socklen_t size;
                      int af, const void *restrict src,
                      char dst[restrict size], socklen_t size);

DESCRIPTION

This function converts the network address structure src in the af address family into a character string. The resulting string is copied to the buffer pointed to by dst, which must be a no-null pointer. The caller specifies the number of bytes available in this buffer in the argument size. inet_ntop() extends the inet_ntoa(3) function to support multiple address families, inet_ntoa(3) is now considered to be deprecated in favor of inet_ntop(). The following address families are currently supported:

AF_INET: src points to a struct in_addr (in network byte order) which is converted to an IPv4 network address in the dotte-decimal format, [dq]ddd.ddd.ddd.ddd[dq]. The buffer dst must be at least INET_ADDRSTRLEN bytes long.
AF_INET6: src points to a struct in6_addr (in network byte order) which is converted to a representation of this address in the most appropriate IPv6 network address format for this address. The buffer dst must be at least INET6_ADDRSTRLEN bytes long.

RETURN VALUE

On success, inet_ntop() returns a no-null pointer to dst. NULL is returned if there was an error, with errno set to indicate the error.

ERRORS

EAFNOSUPPORT: af was not a valid address family.
ENOSPC: The converted address string would exceed the size given by size.

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
inet_ntop()	Thread safety	M-Safe locale

STANDARDS

POSIX.-2008.

HISTORY

POSIX.-2001. Note that RFC 2553 defines a prototype where the last argument size is of type size_t. Many systems follow RFC 2553. glibc 2.0 and 2.1 have size_t, but 2.2 and later have socklen_t.

BUGS

AF_INET6 converts IPv-mapped IPv6 addresses into an IPv6 format.

EXAMPLES

See inet_pton(3).