[ CCode ( has_target = false ) ]
public delegate void SignalCMarshaller (Closure closure, Value? return_value, Value[] param_values, void* invocation_hint, void* marshal_data)

This is the signature of marshaller functions, required to marshall arrays of parameter values to signal emissions into C language callback invocations.

It is merely an alias to ClosureMarshal since the Closure mechanism takes over responsibility of actual function invocation for the signal system.

Namespace: GLib
Package: gobject-2.0