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OpenComm()

Open the communication port to start using it

Syntax:
OpenComm( <cCommName> [,<nSizeIn>] [,<nSizeOut>] ) --> nIdComm

Parameters:
<cCommName> The name of the comm device to open in a format like "COM" + N or "LPT" + N
<nSizeIn> The size in bytes of the receiving queue. This parameter is ignored for "LPT" devices. By default FiveWin assigns 1024.
<nSizeOut> The size in bytes of the transmission queue. This parameter is ignored for "LPT" devices. By default FiveWin assigns 128.

Returns:

<nIdComm> A numeric identifier for that opened device. 0 if there was an error.

If the function fails, it may return one of the following error values:

Value Meaning
IE_BADID The device identifier is invalid or unsupported.
IE_BAUDRATE The device's baud rate is unsupported.
IE_BYTESIZE The specified byte size is invalid.
IE_DEFAULT The default parameters are in error.
IE_HARDWARE The hardware is not available (is locked by another device).
IE_MEMORY The function cannot allocate the queues.
IE_NOPEN The device is not open.
IE_OPEN The device is already open.

If this function is called with both queue sizes set to zero, the return value is IE_OPEN if the device is already open or IE_MEMORY if the device is not open.indows allows COM ports 1 through 9 and LPT ports 1 through 3. If the device driver does not support a communications port number, the OpenComm function will fail.

The communications device is initialized to a default configuration. The SetCommState function should be used to initialize the device to alternate values. The receiving and transmission queues are used by interrupt-driven device drivers. LPT ports are not interrupt driven--for these ports, the cbInQueue and cbOutQueue parameters are ignored and the queue size is set to zero.

Sample:
SAMPLES\\TestComm.prg

Source Code:
SOURCE\\WINAPI\\Comm.c

See also:
CloseComm() WriteComm() ReadComm() BuildCommDcb() SetCommState() FlushComm() GetCommError()