public delegate bool SignalAccumulator (SignalInvocationHint ihint, Value return_accu, Value handler_return, void* data)
The signal accumulator is a special callback function that can be used to collect return values of the various callbacks that are called during a signal emission.
The signal accumulator is specified at signal creation time, if it is left null, no accumulation of callback return values is performed. The return value of signal emissions is then the value returned by the last callback.
Signal invocation hint, see SignalInvocationHint.
Accumulator to collect callback return values in, this is the return value of the current signal emission.
A Value holding the return value of the signal handler.
Callback data that was specified when creating the signal.
The accumulator function returns whether the signal emission should be aborted. Returning true will continue with the signal emission. Returning false will abort the current emission. Since 2.62, returning false will skip to the CLEANUP stage. In this case, emission will occur as normal in the CLEANUP stage and the handler's return value will be accumulated.