# ChangedBlock
<a name="API_ChangedBlock"></a>

A block of data in an Amazon Elastic Block Store snapshot that is different from another snapshot of the same volume/snapshot lineage.

## Contents
<a name="API_ChangedBlock_Contents"></a>

 ** BlockIndex **   <a name="ebs-Type-ChangedBlock-BlockIndex"></a>
The block index.  
Type: Integer  
Valid Range: Minimum value of 0.  
Required: No

 ** FirstBlockToken **   <a name="ebs-Type-ChangedBlock-FirstBlockToken"></a>
The block token for the block index of the `FirstSnapshotId` specified in the `ListChangedBlocks` operation. This value is absent if the first snapshot does not have the changed block that is on the second snapshot.  
Type: String  
Length Constraints: Maximum length of 256.  
Pattern: `^[A-Za-z0-9+/=]+$`   
Required: No

 ** SecondBlockToken **   <a name="ebs-Type-ChangedBlock-SecondBlockToken"></a>
The block token for the block index of the `SecondSnapshotId` specified in the `ListChangedBlocks` operation.  
Type: String  
Length Constraints: Maximum length of 256.  
Pattern: `^[A-Za-z0-9+/=]+$`   
Required: No

## See Also
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For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/ebs-2019-11-02/ChangedBlock) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ebs-2019-11-02/ChangedBlock) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ebs-2019-11-02/ChangedBlock)