Re: [gpsd-dev] [PATCH] Use pselect() to reduce wakeups and avoid race conditions

[Eckhart Wörner]

Hi Håkan,

Am Samstag, 14. Januar 2012, 06:43:08 schrieb Håkan Johansson:
> Regarding (p)select and signal races, I did not see the 'self-pipe trick'
> mentioned in the discussion.  Quoting
> http://www.kernel.org/doc/man-pages/online/pages/man2/select.2.html:
> 
> "On systems that lack pselect(), reliable (and more portable) signal
> trapping can be achieved using the self-pipe trick (where a signal handler
> writes a byte to a pipe whose other end is monitored by select() in the
> main program.)"

I considered using that trick myself, but I refrained from doing so since the 
trick requires a lot of extra code and in general is not that easy to get 
right. [1] contains a discussion of all the steps required.

Eckhart

[1] http://lwn.net/Articles/177897/