hist_access_buffer

Cascade Historian: Version 4.1
Prev |  | Next

# `hist_access_buffer`

`hist_access_buffer` -- accesses buffer elements using array-like syntax.

## Syntax

    hist_access_buffer (buffer, index[, axis])

## Parameters

`buffer`

  A binary buffer of `X`-`Y` pairs of doubles, as created by a call to `hist_buffer_id_read`.

`index`

  The index of the data element to retrieve from the buffer.

`axis`

  An optional string indicating which value of the of the data pair to access, `"X"` or `"Y"`.

## Returns

If `axis` is specified, then the corresponding real-valued data at the `index`. If `axis` is not specified, then an instance of the `HI_stVALUE` class containing the data at the `index`. If an error occurs, then `nil` is returned and `_last_error_` is set to one of the following possible errors:

        "Invalid axis specifier: axis"
        "Index out of range: index"
        "Buffer empty"

## Description

This function provides access to the elements of the buffer as if it were an array.

## Example

        Gamma> hist_access_buffer(buf, 2, "X");
        1025721206.20266
        Gamma> hist_access_buffer(buf, 2, "Y");
        102.1
        Gamma> hist_access_buffer(buf, 2);
        {HI_stVALUE (value . 102.1) (xaxis . 1025721206.20266)}

Prev | Home | Next
Dynamic Library Functions | Up | `hist_buffer2array`

Copyright 1995-2002 by Cogent Real-Time Systems, Inc.