[#btcsignals-signal]
= xref:btcsignals.adoc[btcsignals]::signal
:relfileprefix: ../
:mrdocs:

Functor for calling zero or more connected callbacks.

== Synopsis

Declared in `<util/btcsignals.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename Signature,
    typename Combiner = xref:btcsignals/null_value.adoc[null_value]>
class signal;
----

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:btcsignals/signal/result_type.adoc[`result_type`] 
| The result type of invoking the signal, taken from the combiner.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:btcsignals/signal/2constructor-0d.adoc[`signal`]         [.small]#[constructor]#
| Constructors
| xref:btcsignals/signal/2destructor.adoc[`~signal`] [.small]#[destructor]#
| Destroy the signal and drop all connection state.
| xref:btcsignals/signal/operator_assign-02.adoc[`operator=`] 
| Assignment operators
| xref:btcsignals/signal/connect.adoc[`connect`] 
| Connect a new callback to the signal. A forwarding callable accepts anything that can be stored in a std::function.
| xref:btcsignals/signal/empty.adoc[`empty`] 
| Returns true if there are no enabled callbacks.
| xref:btcsignals/signal/operator_call.adoc[`operator()`] 
| Execute all enabled callbacks for the signal. Rather than allowing for custom combiners, the behavior of any_of is hard‐coded here.
|===


== Template Parameters

[cols="1,4"]
|===
| Name| Description
| *Signature*
| The callable signature accepted by connected callbacks.
| *Combiner*
| The combiner that determines the signal's result type.
|===


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