[#CalculateLockPointsAtTip]
= CalculateLockPointsAtTip
:mrdocs:

Calculate LockPoints required to check if transaction will be BIP68 final in the next block to be created on top of tip.

== Synopsis

Declared in `<validation.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
std::optional<LockPoints>
CalculateLockPointsAtTip(
    xref:CBlockIndex.adoc[CBlockIndex]* tip,
    xref:CCoinsView.adoc[CCoinsView] const& coins_view,
    xref:CTransaction.adoc[CTransaction] const& tx);
----

== Return Value

The resulting height and time calculated and the hash of the block needed for calculation, or std::nullopt if there is an error.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *tip* [in]
| Chain tip for which tx sequence locks are calculated. For example, the tip of the current active chain.
| *coins_view* [in]
| Any CCoinsView that provides access to the relevant coins for checking sequence locks. For example, it can be a CCoinsViewCache that isn't connected to anything but contains all the relevant coins, or a CCoinsViewMemPool that is connected to the mempool and chainstate UTXO set. In the latter case, the caller is responsible for holding the appropriate locks to ensure that calls to GetCoin() return correct coins.
| *tx* [in]
| The transaction being evaluated.
|===


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