hist_length
hist_length — finds the total number of values in a history.
Syntax
hist_length (hist_task, history[, start[, end]])
Parameters
- hist_task
- The task object corresponding to the
Cascade Historian. See locate_task
in the Gamma manual.
- history
- The name of the history to be queried.
- start
- Optional, the start of a desired time range in
seconds, expressed as a real number. The default is the
first value available.
- end
- Optional, the end of a desired time range in seconds,
expressed as a real number. The default is the last value
available.
Returns
The number of values collected by the
history between the specified times, if successful. Otherwise
returns nil
and sets _last_error_ to the error string
returned by the Cascade Historian.
Description
This function queries the history for the total number of values
available.
This function corresponds to the length command, and
the Cogent C API function HI_Length.
