[#wallet-AttemptSelection]
= xref:wallet.adoc[wallet]::AttemptSelection
:relfileprefix: ../
:mrdocs:

Attempt to find a valid input set that preserves privacy by not mixing OutputTypes. `ChooseSelectionResult()` will be called on each OutputType individually and the best the solution (according to the waste metric) will be chosen. If a valid input cannot be found from any single OutputType, fallback to running `ChooseSelectionResult()` over all available coins.

== Synopsis

Declared in `<wallet/spend.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:util/Result.adoc[util::Result<SelectionResult>]
AttemptSelection(
    xref:interfaces/Chain.adoc[interfaces::Chain]& chain,
    xref:CAmount.adoc[CAmount] const& nTargetValue,
    xref:wallet/OutputGroupTypeMap.adoc[OutputGroupTypeMap]& groups,
    xref:wallet/CoinSelectionParams.adoc[CoinSelectionParams] const& coin_selection_params,
    bool allow_mixed_output_types);
----

== Return Value

If successful, a SelectionResult containing the input set If failed, returns (1) an empty error message if the target was not reached (general "Insufficient funds") or (2) a specific error message if there was something particularly wrong (e.g. a selection result that surpassed the tx max weight size).

== Parameters

[cols="1,4"]
|===
| Name| Description
| *chain* [in]
| The chain interface to get information on bump fees for unconfirmed UTXOs
| *nTargetValue* [in]
| The target value
| *groups* [in]
| The grouped outputs mapped by coin eligibility filters
| *coin_selection_params* [in]
| Parameters for the coin selection
| *allow_mixed_output_types* [in]
| Relax restriction that SelectionResults must be of the same OutputType
|===


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