Re: [Gcc4cli-devel] gettimeofday

[Erven R. <erv...@in...>]

I do not have any definite answer.
But time_t has a wiki page!!!   http://en.wikipedia.org/wiki/Time_t

The standard does not specify the type. Instead there is:
double difftime(time_t time1, time_t time0);

Excerpt from the man:
        On  a  POSIX  system,  time_t is an arithmetic type, and one could just
        define
               #define difftime(t1,t0) (double)(t1 - t0)
        when the possible overflow in the subtraction is  not  a  concern.   On
                 ^^^^^^^^^^^^^^^^^^
        other systems, the data type time_t might use some other encoding where
        subtraction doesn't work directly.



My understanding is that it is not safe to rely on the signedness of time_t.
But we probably increase our level our bug-compatibility if we use the same as 
GNU lib C.

My only concern: is this going to break anything else?

Thoughts?

--
Erven.


Kevin Williams a écrit :
> Hi all,
> 
> I have noticed that gcc4cli declares time_t as an 'unsigned long'.
> The GNU C lib declares it as 'signed long'.
> 
> This difference causes getimeofday to report incorrect numbers when
> using the common function.....
> 
> double time = (endTime.tv_sec - startTime.tv_sec) + ( (endTime.tv_usec
> - startTime.tv_usec) / 1.e6);
> 
> 
> was time_t declared as unsigned long for a reason?
> If not can we change it to signed?
> 
> Thanks,
> Kevin