---
name: "VistaIODecodeAttrValue"
section: "3"
platform: "linux"
package: "libvistaio-dev"
version: "1.2.19-3+b2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/VistaIODecodeAttrValue"
---

# VistaIODecodeAttrValue(3)

decode an attribute value

## NAME

VistaIODecodeAttrValue - decode an attribute value

## SYNOPSIS

```
VistaIOBoolean VistaIODecodeAttrValue (str, dict, repn, value)
VistaIOStringConst str;
VistaIODictEntry *dict;
VistaIORepnKind repn;
VistaIOPointer value;
```

## ARGUMENTS

- *str*

  **Specifies the attribute value to be decoded.**

- *dict*

  **May specify a dictionary to be used in recognizing the value supplied** **as a keyword, or it may be** **NULL**

- *repn*

  **Specifies the representation in which the value is to be returned. It must**  **be one of VistaIOBitRepn, VistaIOUByteRepn, VistaIOSByteRepn,**  **VistaIOShortRepn, VistaIOLongRepn, VistaIOFloatRepn, VistaIODoubleRepn,**  **VistaIOBooleanRepn, or VistaIOStringRepn.**

- *value*

  **Specifies a location at which the value is be returned.**

## DESCRIPTION

**VistaIODecodeAttrValue decodes the string** *str***, returning its value in**  **the form specified by** *repn***.**

**If a dictionary,** *dict***, has been provided, the routine determines**  **whether** *str* **is a keyword defined in the dictionary. If so, it uses**  **the value associated with that keyword rather than the attribute's original**  **value. (See the [VistaIOdictionary(3)](/VistaIOdictionary/3.md) manual page.)**

**The value obtained directly from** *str***, or indirectly via the**  **dictionary, is converted to the representation** *repn* **and then stored**  **at the location pointed to by** *value***.**

## RETURN VALUES

**VistaIODecodeAttrValue returns** **TRUE** **if successful and** **FALSE** **otherwise. It will fail if** *repn* **is invalid, or if the** *str*  **cannot be interpreted as a value of the type indicated by** *repn***.**

## SEE ALSO

[**VistaIOEncodeAttrValue**(3)](/VistaIOEncodeAttrValue/3.md), [**VistaIOGetAttr**(3)](/VistaIOGetAttr/3.md), [**VistaIOattribute**(3)](/VistaIOattribute/3.md),

## NOTES

**The** *value* **argument must point to sufficient storage to contain a**  **value of the representation requested. Neither VistaIODecodeAttrValue nor**  **the C compiler can automatically check that this is so.**

## DIAGNOSTICS

- \`\`Can't decode to *repn*.''

  **The** *repn* **argument is not one of VistaIOBitRepn, VistaIOUByteRepn, ...,** **VistaIOBooleanRepn, or VistaIOStringRepn.**

## AUTHOR

**Art Pope \<pope@cs.ubc.ca\>**

**Adaption to vistaio: Gert Wollny \<gw.fossdev@gmail.com\>**