4.1 Functions of the serial interface
● If "COM_OPEN_STD_PUF" is transferred as the buffer size, the buffer size from the
● The returned handle must be transferred as a parameter with all further calls.
● Each buffer can hold several frames at the same time. The number is restricted only by
This function is used for the blocking receipt of frames.
● The call blocks if no frame is present. No timeout parameter is intended.
● This call fetches incoming frames from an internal buffer. The actual receive routine is
parameter assignment dialog is adopted.
the total of the lengths of all buffered frames.
interface handle from
Pointer to the receive buffer of the caller
Length of the receive buffer
Number of bytes read (≙ frame length)
possible error message:
Installation Manual, 01/2013, J31069-D0131-U001-A2-7218
SIMATIC 3964R protocol for Windows 9x/XP/7