recvfrom()

データ(とIPAddress, Port番号)を取得
int recvfrom (
  int s,
  char * buf,
  int len,
  int flags,
  struct sockaddr * from,
  int * fromlen
);

s

• [in] Descriptor identifying a bound socket.

buf

• [out] Buffer for the incoming data.

len

• [in] Length of buf, in bytes.

flags

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

from

• [out] Optional pointer to a buffer in a sockaddr structure that will hold the source address upon return.

fromlen

• [in, out] Optional pointer to the size, in bytes, of the from buffer.