dciListClassId returns one of the following values:
DCI_SUCCESS
The DCIReturn structure has been written
to the output buffer.
DCI_NOTINITIALIZED
The requester has not yet
initialized the DCI.
DCI_SYSERROR
A internal error has occurred
(such as a shortage of resources) that may be beyond the control of the
application.
DCI_INVALIDARG
One of the input arguments
is invalid. For example, a negative value was used for numIds or bufferSize.
Also, either metricIdList could not be read or buffer could not be written.