CancelableWait in misc.c should check for negative timeout

CancelableWait in misc.c should check for negative timeout

[Tor Lillqvist]

I think the function CancelableWait should check for timeout being
negative (when casted to an int, that is). This can happen if you call
pthread_cond_timedwait with an abstime that's already gone, because of
some rounding error or slightly incorrect handling of various
timestamp formats. It happens for instance in GLib's testgthread
program. If timeout is negative, it probably should be treated as
zero.

In CancelableWait, before calling WaitForMultipleObjects, insert:

  if (((int) timeout) < 0)
    timeout = 0;

Cheers,
--tml

Re: CancelableWait in misc.c should check for negative timeout

[Tor Lillqvist]

Tor Lillqvist writes:
 >   if (((int) timeout) < 0)
 >     timeout = 0;

Actually, as INFINITE is 0xFFFFFFFF, i.e. -1, this code snippet
shouldn't be in CancelableWait, but in pthreadCancelableTimedWait.

--tml

Re: CancelableWait in misc.c should check for negative timeout

[Ross Johnson]

Hi Tor,

On Thu, 25 Mar 1999, Tor Lillqvist wrote:

> Tor Lillqvist writes:
>  >   if (((int) timeout) < 0)
>  >     timeout = 0;
> 
> Actually, as INFINITE is 0xFFFFFFFF, i.e. -1, this code snippet
> shouldn't be in CancelableWait, but in pthreadCancelableTimedWait.
> 

I'm thinking that the check should go in _pthread_sem_timedwait
which does the conversion from an abstime value to milliseconds.

pthreadCancelableTimedWait is called by _pthread_sem_timedwait which
is called by pthread_cond_timedwait.

The reason is: I think that the millisecond timeout argument for
pthreadCancelableTimedWait should behave the same as for
WaitForMultipleObjects.

Ross

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