why is the alarm thread used instead of SO_SNDTIMEO and SO_RCVTIMEO

[MARK CALLAGHAN]

I describe how I think read/write is done for sockets in mysqld.
http://www.facebook.com/note.php?note_id=122655300932

Can someone explain the history of this code? That is, why was the
alarm thread used for read/write timeouts rather than
SO_SNDTIMEO/SO_RCVTIMEO?

Has anyone had success defining NO_ALARM so that SO_SNDTIMEO and
SO_RCVTIMEO are used? I will soon try that myself. Well, I assume that
NO_ALARM will do that but I have to look at the preprocessor output as
the code in question is full of ifdefs.

-- 
Mark Callaghan
mdcallag@stripped