HI_Length

Cogent API and Utilities: Version 4.1
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# `HI_Length`

`HI_Length` -- finds the total number of values in a history.

## Syntax

    #include <cogent/cogent.h>

``ST_STATUS HI_Length`(IP_hTASK historian, char* retbuf, int buflen, char* histname, int* length);`

## Arguments

`historian`

  The task pointer to the Cascade Historian program.

`retbuf`

  An optional buffer containing an error message.

`buflen`

  The length in bytes of `retbuf`. If `retbuf` is non-NULL, this must be a valid non-zero length. If `retbuf` is NULL, this parameter is ignored.

`histname`

  The name of a history.

`length`

  The return value containing the number of values in the history.

## Returns

`ST_OK` on success. Otherwise `ST_ERROR`, and the `retbuf` will contain a NULL-terminated character string with an error message. If the return value is `ST_OK`, the `retbuf` may not contain useful information.

## Description

This function queries the history for the total number of values available. It returns the result in `length`.

This function corresponds to the Cascade Historian length command and the `hist_length` dynamic library function.

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