registerPoint
registerPoint — registers to receive updates from a DataHub
point.
Syntax
For C++:
ST_STATUS registerPoint( | CDataHubPoint& | point, |
| | bool | create=TRUE); |
ST_STATUS registerPoint( | LPCTSTR | pointname, |
| | bool | create=TRUE); |
For Java:
Exception registerPoint( | DataHubPoint | point, |
| | boolean | create); |
Exception registerPoint( | String | pointname, |
| | boolean | create); |
For C#:
Exception registerPoint( | DataHubPoint | point, |
| | bool | create); |
Exception registerPoint( | String | pointname, |
| | bool | create); |
Parameters
- point
- A
DataHubPoint object. The name
member must be valid.
- pointname
- The name of the point.
- create
- If
TRUE, then the point is created if it does
not already exist. If FALSE and the point
does not exist, then an error message will be
generated.
Returns
For C++:
- ST_OK if the command
was successfully sent to the DataHub. Since the
command is sent asynchronously, the actual success or
failure of the command must be determined through the
onSuccess
or onError
message handlers.
- ST_NO_TASK if a connection to
the DataHub does not exist.
- ST_ERROR if the connection
socket is unable to send the message.
Description
When a point is registered with
the DataHub, any changes to the value of that point in the
DataHub will cause the onPointChange method to be
called. If the DataHub point does not exist, then
the DataHub will respond with an error, and onError will be called with the
following arguments:
| status: ST_NO_POINT |
| msg: "Point does not exist" |
