> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
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# SetParallelProcessingCallback Method of the Engine Object

<Note>
  This method is implemented in FRE for Linux and Windows.
</Note>

This method allows you to specify the user-implemented object supporting the [IParallelProcessingCallback](/fine-reader/engine/api-reference/supplementary-objects-and-methods/iparallelprocessingcallback) interface, which will be used to send error notifications during parallel processing.

## Syntax

### C++

```cpp theme={null}
HRESULT SetParallelProcessingCallback( IParallelProcessingCallback* Callback );
```

### C\#

```csharp theme={null}
void SetParallelProcessingCallback( IParallelProcessingCallback Callback );
```

### Visual Basic .NET

```vb theme={null}
Sub SetParallelProcessingCallback(Callback As IParallelProcessingCallback)
```

## Parameters

Callback

\[in] This parameter refers to the interface [IParallelProcessingCallback](/fine-reader/engine/api-reference/supplementary-objects-and-methods/iparallelprocessingcallback).

## Return values

This method has no specific return values. It returns the [standard return values of ABBYY FineReader Engine functions](/fine-reader/engine/api-reference/return-codes).

## Remarks

For Linux, this method does not work if the Engine object is loaded as an out-of-process server.

## See also

[Engine](/fine-reader/engine/api-reference/engine-object-iengine-interface)