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# GetImmutableHintValue

Reads an immutable value stored by the plug-in authorization mechanism.

```
int (*)(struct __OpaqueAuthorizationEngine *, const char *, const struct AuthorizationValue **) GetImmutableHintValue;
```

## Parameters

`inEngine`

An opaque handle that is passed to your plug-in when the authorization engine calls your [`MechanismCreate`](/documentation/Security/AuthorizationPluginInterface/MechanismCreate) function.

`inKey`

A key indicating which value you want to retrieve. This key must correspond to one you specified when you used the [`SetHintValue`](/documentation/Security/AuthorizationCallbacks/SetHintValue) function to store a hint value.

`outValue`

On input, allocate a pointer to an [`AuthorizationValue`](/documentation/Security/AuthorizationValue) structure. On output, the structure contains the size of the data and a pointer to the data. Because your [`AuthorizationValue`](/documentation/Security/AuthorizationValue) structure does not own the data, you must not deallocate the structure or the data pointed to by the structure.

## Return Value

A result code. Possible results are [`errAuthorizationSuccess`](/documentation/Security/errAuthorizationSuccess) (no error) and [`errAuthorizationInternal`](/documentation/Security/errAuthorizationInternal) (Security Server internal error).

## Discussion

This function behaves like [`GetHintValue`](/documentation/Security/AuthorizationCallbacks/GetHintValue), except that the hint is immutable.

---

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