hist_buffer_id_length

Cascade Historian: Version 4.1
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# `hist_buffer_id_length`

`hist_buffer_id_length` -- queries for the number of `X`-`Y` pairs.

## Syntax

    hist_buffer_id_length (hist_task, queryid)

## Parameters

`hist_task`

  The task object corresponding to the Cascade Historian. A task object is created by a call to the Gamma function `locate_task`, as follows:

          hist_task = locate_task ("tfrc/histdb", nil);

`queryid`

  The reference number for the result of a query made on the Cascade Historian using the `hist_interpolate` function or the interpolate command.

## Returns

The number of `X`-`Y` data pairs, an integer-valued number.

## Description

This function queries the Cascade Historian for the number of `X`-`Y` pairs (the buffer length) in the result of an interpolate query. This value can be used to request the buffer from the Cascade Historian with the `hist_buffer_id_read` function.

This function corresponds in part to the bufferIdLength command and the Cogent API function `HI_BufferIDLength`.

## Example

See the example for hist_exchange_buffer.

## See also

hist_interpolate

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