TIdStack.ReceiveFrom Method

Receives a datagram using a socket handle and stores the source address.

Pascal

function ReceiveFrom(
    ASocket: TIdStackSocketHandle; 
    var VBuffer: TIdBytes; 
    var VIP: string; 
    var VPort: Integer; 
    const AIPVersion: TIdIPVersion = ID_DEFAULT_IP_VERSION
): Integer; virtual; abstract;

Parameters

Parameters	Description
ASocket	Socket handle for the operation.
VIP	IP address for the remote network.
VPort	Port number for the remote network.
AIPVersion	IP address family for the IP address.
ABuffer	Buffer used to store values read from the socket handle.

Returns

Integer - Number of bytes read from the socket handle.

Description

ReceiveFrom is an abstract virtual Integer function that specifies the method used to access the RecvFrom() API for a protocol stack implementation.

ReceiveFrom reads data from the socket handle in ASocket, and stores the remote destination IP address and port number in VIP and VPort. Byte values read from the socket are stored in the ABuffer argument.

The return value for the method is the number of bytes read from the socket handle, or 0 (zero) when the connection has been closed gracefully.

AIPVersion indicates the IP address family supported for transmission on the socket handle.

ReceiveFrom must be overriddden and implemented in a descendant class that provides access to the protocol stack for the platform or operating system hosting the Indy library.

Use ReceiveMsg to capture data for message-oriented datagram transmissions using UDP or IP multicast.