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sendto.md

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Function name : sendto

Group: Windows Sockets 2 (Winsock) - Library: ws2_32

Sends data to a specific destination.

Code examples:

How to build UDP responder

Declaration:

int sendto(
  SOCKET s,
  const char* buf,
  int len,
  int flags,
  const struct sockaddr* to,
  int tolen
);

FoxPro declaration:

DECLARE INTEGER sendto IN ws2_32;
	INTEGER s,;
	STRING @buf,;
	INTEGER buflen,;
	INTEGER wsflags,;
	STRING @sendto,;
	INTEGER tolen

Parameters:

s [in] Descriptor identifying a (possibly connected) socket.

buf [in] Buffer containing the data to be transmitted.

len [in] Length of the data in buf, in bytes.

flags [in] Indicator specifying the way in which the call is made.

to [in] Optional pointer to a sockaddr structure that contains the address of the target socket. tolen [in] Size of the address in to, in bytes.

Return value:

If no error occurs, sendto returns the total number of bytes sent, which can be less than the number indicated by len. Otherwise, a value of SOCKET_ERROR is returned, and a specific error code can be retrieved by calling WSAGetLastError.

Comments:

The sendto function is normally used on a connectionless socket to send a datagram to a specific peer socket identified by the to parameter. Even if the connectionless socket has been previously connected to a specific address, the to parameter overrides the destination address for that particular datagram only.

On a connection-oriented socket, the to and tolen parameters are ignored, making sendto equivalent to send.