Parameter values returned to the application

BUF

Defines an input buffer to receive the input data.

NAME

An IPv4 socket address structure containing the address of the socket that sent the data. The structure is as follows:

FAMILY: A halfword binary number specifying the IPv4 addressing family. The value is always decimal 2, indicating AF_INET.
PORT: A halfword binary number specifying the port number of the sending socket.
IP-ADDRESS: A fullword binary number specifying the 32-bit IPv4 IP address of the sending socket.
RESERVED: An 8-byte reserved field. This field is required, but is not used.

An IPv6 socket address structure containing the address of the socket that sent the data. The structure is as follows:

Field: Description
FAMILY: A halfword binary number specifying the IPv6 addressing family. The value is decimal 19, indicating AF_INET6.
PORT: A halfword binary number specifying the port number of the sending socket.
FLOWINFO: A fullword binary field specifying the traffic class and flow label. This value of this field is undefined.
IP-ADDRESS: A 16-byte binary field set to the 128-bit IPv6 IP address of the sending socket.
SCOPE-ID: A fullword binary field which identifies a set of interfaces as appropriate for the scope of the address carried in the IPv6-ADDRESS field. For a link scope IPv6-ADDRESS, SCOPE-ID contains the link index for the IPv6-ADDRESS. For all other address scopes, SCOPE-ID is undefined.

ERRNO

A fullword binary field. If RETCODE is negative, the field contains an error number. See Socket call error return codes for information about ERRNO return codes.

RETCODE

A fullword binary field that returns one of the following values:

Value: Description
0: The socket is closed.
>0: A positive return code indicates the number of bytes of data transferred by the read call.
-1: Check ERRNO for an error code.