UDT Reference: Functions

recvfile

The recvfile method reads certain amount of data into a local file.

int64_t recvfile(
  UDTSOCKET u,
  fstream& ofs,
  int64_t& offset,
  int64_t size,
  int block = 366000
);
Parameters
u
[in] Descriptor identifying a connected socket.
ofs
[in] C++ fstream descriptor for the file to store incoming data.
offset
[in, out] The offset position from where the data is written into the file; after the call returns, this value records the new offset of the write position.
size
[in] The total size to be received.
block
[in] Optional. The size of every data block for file IO.
Return Value

On success, recvfile returns the actual size of received data. Otherwise UDT::ERROR is returned and specific error information can be retrieved by getlasterror.

Error Name Error Code Comment
ECONNLOST 2001 connection has been broken and no data left in receiver buffer.
ENOCONN 2002 u is not connected.
EFILE 4000 File or disk system errors.
EINVSOCK 5004 u is not an valid socket.
EDGRAMILL 5010 cannot use recvfile in SOCK_DGRAM mode.
Description

The recvfile method reads certain amount of data and write it into a local file. It is always in blocking mode and neither UDT_RCVSYN nor UDT_RCVTIMEO affects this method. The actual size of data to expect must be known before calling recvfile, otherwise deadlock may occur due to insufficient incoming data.

See Also

send, sendfile, recv