WireWare native: WireWare GetDatapointValueLength

Summary

Retrieves the contents and the current length of a datapoint.

WIREWARE_RESULT WireWare_GetDatapointValueLength (

WIREWARE_DATAPOINT_HANDLE	handle	// handle for datapoint
void*	data	// pointer to buffer for contents
int*	length	// pointer to memory location for current length
WIREWARE_TIMEOUT	maxAge	// max age of cached data in ms
WIREWARE_TIMEOUT	timeout	// timeout in ms

);

handle	Specifies the handle for the datapoint.
data	Specifies a memory location, which receives the contents of the datapoint. The find out the required buffer size, use the function WireWare_GetDatapointMaximumLength.
length	Specifies a memory location, which receives the current length of the datapoint.
maxAge	Specifies the maximum age of the returned value in ms. If the value in the local data cache is older than the given time in ms, the WireWare subsystem retrieves the current value from the machine or device.
timeout	Specifies the maximum allowed execution time (in ms) for this function.

If the function succeeds, the return value is WIREWARE_ERROR_NONE. Otherwise it returns an appropriate error code.

If the function returns WIREWARE_ERROR_HANDLE_MEANINGLESS, the connection dropped and has to be closed.

This function retrieves the contents and the current length of the datapoint, which is referred to by the handle.

The function takes care, that the returned value is not older than maxAge in ms.