[Developers] flush-ing stdout in cctk_vinfo

[Tom Goodale]

On Wed, 31 Jan 2007, Jonathan Thornburg wrote:

> Hi,
>
> I wrote
>> In my opinion, the fact that Bela used  --buffering line , yet (as I
>> understand it) found additional output appearing when he did explicit
>> flushes, constitutes a bug of some sort.  I'm not quite sure whether
>> it's caused by stdout and stderr not being synchronized, or a bug in
>> stdio that isn't handling line buffering properly, but from the user's
>> perspective, asking for  --buffering line  and not getting it constitues
>> a bug.
>>
>> Given this, IMHO Bela's suggestion is a reasonable workaround, which
>> would certainly avoid the bug in many, albeit not all, cases.  That is,
>> we would change the code so that if  --buffering line  is specified,
>> CCTK_VInfo() does an explicit  fflush(stdout)  just before returning.
>
> Sorry, I now realise bela specified   -bno   .  But I think this
> makes the case even stronger -- he asked for *no* output buffering,
> but yet there clearly was some buffering (since explicit flushing
> gave additional output).

There's definitely a bug somewhere, so putting the fflush in would work 
around it, at least for output using CCTK functions. However I think the 
problem is with the redirection to the CCTK_Proc... files happening after 
the buffering has been set - freopen is equivalent to fclose followed by 
fopen.  I think we just need to move some code about to have code which 
will work even when non CCTK functions output.

Cheers,

Tom