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.
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.