Subj : Re: usage of time() for timeout handling
To   : comp.arch.embedded,comp.programming
From : Ed Prochak
Date : Thu Jul 28 2005 03:22 pm

and worrying about changing clock settings isn't a problem? the other
solutions all proposed some workaround to calling time(). They all
suffer the reversed clock problem (except for Dan).

The OP asked about timeout and specifically mentioned resolutions on
level of whole seconds. (he's currentlly calling the time() function.)
He made no explicit mention of needing more than one timeout. But if he
does, then he just needs some cooperation between the different
timeouts. It would be easy to set up shared functions that allow him
to:
create a timeout
cancel a timeout
start a timeout for a given number of seconds
with a SIGALARM handler function that uses the data created by those
functions to provide multiple timeouts.
IF he needs this he should be able to program it. This isn't a
difficult thing. Not much more work than what you would do with
start/stop values. He could put all these functions in another small
module.

And yes it is possible to send a SIGALRM from something other than the
alarm(). (And you better read all of the alarm() manpage for other side
effects.) But the point is  the system clock can be changed all they
want, his code will not be effected. And I presented a function that
doesn't have that problem.

So unless there is a special function in his OS/language for this, I
think alarm() is the best choice.

  Ed

.