Calling functions from std::signal handler; SIGWINCH

Question

I need to capture the event of a terminal resize, to do this I am capturing (although other methods are welcome) SIGWINCH with the following:

std::signal(SIGWINCH, &handle_sigwinch);

I was then hoping to have handle_sinwinch do something like:

display_type *dt; //inited elsewhere

void handle_sinwinch(int sig) {
    dt->async_redraw();
}

Where async_redraw post the work to do onto an internal boost::asio::io_service and then returns. Thus there should be no race conditions; however, the doc for std::signal seems to imply that I can safely ONLY manipulate volatile std::sig_atomic_ts.

IE I can set a flag, then pick it up from the main thread as a part of an event loop.

The problem is that this is asynchronous so there is no while(true) loop or anything like that. The only way to loop over such a flag would be to create a deadline timer and check it periodically. Which seems like a real hack.

So my question is, is my understanding of signals correct? And any insight how to do this would be appreciated.

Answer 1

If you use boost::asio you can handle signals with async_wait() method of boost::asio::signal_set. Handler set with async_wait() can do what you want, it is not called in signal handler context.