af Specifies the address family. Valid values are AF_INET for an IPv4 address and AF_INET6 for an IPv6 address. src Points to a buffer that contains the numeric IP address. dst Points to a buffer that is to contain the text string. size Specifies the size of the buffer pointed to by the dst parameter. For IPv4 addresses, the minimum buffer size is 16 bytes. For IPv6 addresses, the minimum buffer size is 46 bytes. INET_ADDRSTRLEN constants are defined in the IN.H header file. INET6_ADDRSTRLEN constants are defined in IN6.H.