NOTE: click here if you get an empty page.

inet_ntop(3)		   Linux Programmer's Manual		  inet_ntop(3)


inet_ntop - Parse network address structures


#include <sys/types.h> #include <sys/socket.h> #include <arpa/inet.h> const char *inet_ntop(int af, const void *src, char *dst, socklen_t cnt);


This function converts the network address structure src in the af address family into a character string, which is copied to a character buffer dst, which is cnt bytes long. inet_ntop(3) 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(3). The following address families are currently supported: AF_INET src points to a struct in_addr (network byte order format) which is converted to an IPv4 network address in the dotted-quad for- mat, "ddd.ddd.ddd.ddd". The buffer dst must be at least INET_ADDRSTRLEN bytes long. AF_INET6 src points to a struct in6_addr (network byte order format) 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.


inet_ntop() returns a non-null pointer to dst. NULL is returned if there was an error, with errno set to EAFNOSUPPORT if af was not set to a valid address family, or to ENOSPC if the converted address string would exceed the size of dst given by the cnt argument.


POSIX.1-2001. Note that RFC 2553 defines a prototype where the last parameter cnt is of type size_t. Many systems follow RFC 2553. Glibc 2.0 and 2.1 have size_t, but 2.2 has socklen_t.




AF_INET6 converts IPv6-mapped IPv4 addresses into an IPv6 format. Linux Man Page 2000-12-18 inet_ntop(3)

1994 Man-cgi 1.15, Panagiotis Christias <>