[#node-BlockManager-LookupBlockIndex-02]
= xref:node.adoc[node]::xref:node/BlockManager.adoc[BlockManager]::LookupBlockIndex
:relfileprefix: ../../
:mrdocs:

Look up a block index entry by hash.

== Synopsis

Declared in `<node/blockstorage.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[requires_capability(0x7ff37af16a18), requires_capability(0x7ff376b839f8), requires_capability(0x7ff37ded15e8), requires_capability(0x7ff36c616808), requires_capability(0x7ff37c49a668), requires_capability(0x7ff39283d068)]]
xref:CBlockIndex.adoc[CBlockIndex]*
LookupBlockIndex(xref:uint256.adoc[uint256] const& hash);
----

== Return Value

The block index entry, or nullptr if the hash is unknown.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *hash*
| The block hash to look up.
|===


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