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Socket::ReceiveMessageFrom Method

Receives the specified number of bytes of data into the specified location of the data buffer, using the specified SocketFlags, and stores the endpoint and packet information.

Namespace:  System.Net.Sockets
Assembly:  System (in System.dll)
int ReceiveMessageFrom(
	array<unsigned char>^ buffer, 
	int offset, 
	int size, 
	SocketFlags% socketFlags, 
	EndPoint^% remoteEP, 
	[OutAttribute] IPPacketInformation% ipPacketInformation


Type: array<System::Byte>

An array of type Byte that is the storage location for received data.

Type: System::Int32

The position in the buffer parameter to store the received data.

Type: System::Int32

The number of bytes to receive.

Type: System.Net.Sockets::SocketFlags%

A bitwise combination of the SocketFlags values.

Type: System.Net::EndPoint%


Type: System.Net.Sockets::IPPacketInformation%

An IPPacketInformation holding address and interface information.

Return Value

Type: System::Int32
The number of bytes received.

buffer is nullptr.

- or-

remoteEP is nullptr.


offset is less than 0.


offset is greater than the length of buffer.


size is less than 0.


size is greater than the length of the buffer minus the value of the offset parameter.


socketFlags is not a valid combination of values.


The LocalEndPoint property was not set.


The .NET Framework is running on an AMD 64-bit processor.




The Socket has been closed.



The ReceiveMessageFrom method reads data into the buffer parameter, returns the number of bytes successfully read, and captures the remote host endpoint from which the data was sent, as well as information about the received packet.

The ReceiveMessageFrom method is used primarily to receive message data on a connectionless socket. The socket's local address must be known. This method can only be used with datagram and raw sockets. The socket must be initialized with the socket type set to Dgram or Raw before calling this method. This can be done when the socket is constructed using Socket.

For message-oriented sockets, an incoming message is placed into the buffer parameter up to the total size specified in the size parameter. The offset parameter determines where in the buffer the data is placed. The actual amount of data placed into the buffer is returned by the ReceiveMessageFrom method.

The ReceiveMessageFrom method automatically method sets the PacketInformation socket option to true the first time it is called for a given Socket. However, the returned IPPacketInformation object will only be valid for packets which arrive at the local computer after the socket option has been set. If a socket is sent packets between when it is bound to a local endpoint (explicitly by the Bind method or implicitly by one of the Connect, ConnectAsync, SendTo, or SendToAsync methods) and its first call to the ReceiveMessageFrom method, calls to ReceiveMessageFrom method will return invalid IPPacketInformation objects for these packets.

To ensure that all IPPacketInformation objects are valid, an application should set the PacketInformation socket option to true before it is bound to a local endpoint using the SetSocketOption(SocketOptionLevel, SocketOptionName, Boolean) method.

An application can examine the ipPacketInformation parameter if it needs to know if the datagram was sent using a unicast, multicast, or broadcast address.





.NET Framework


.NET Framework Client Profile

Supported in: 4, 3.5 SP1



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