id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
8738,Signal number = 0 in signal_set handler.,alxn1@…,chris_kohlhoff,"In boost/asio/detail/impl/signal_set_service.ipp, if signal occured, but currently handlers queue is empty, signal_set_service will increment undelivered_ variable, but not save signal number. After what, if new handler will added, it will be called with zero signal number immediately, and undelivered_ decremented:

    if (reg->undelivered_ > 0)
    {
      --reg->undelivered_;
      io_service_.post_deferred_completion(op);
      return;
    }

but signal number doesn't set (op->signal_number_ == 0 in this place).

I think, it's bug :)

It's can be reproduced with small test utility (in attachment): compile it, start, and post to it 10-15 SIGHUP's (kill -s SIGHUP <pid> | kill -s SIGHUP <pid> | kill -s SIGHUP <pid> | kill -s SIGHUP <pid> ...).
In stdout you will see:

signal 1 received
signal 1 received
signal 1 received
signal 1 received
signal 1 received
signal 1 received
signal 1 received
signal 1 received
signal 0 received
signal 1 received
signal 1 received
signal 1 received
signal 1 received
signal 0 received
signal 1 received

In some cases signal number is zero.
",Bugs,closed,To Be Determined,asio,Boost 1.53.0,Problem,fixed,asio signal_set signo,