(unknown)

* (unknown)
@ 2004-08-24  6:05 Francisco M. Marzoa Alonso
  2004-08-24  9:39 ` your mail Jan-Benedict Glaw
  0 siblings, 1 reply; 51+ messages in thread
From: Francisco M. Marzoa Alonso @ 2004-08-24  6:05 UTC (permalink / raw)
  To: linux-serial

>>       TOut.tv_sec = Wait / 1000;
>>       TOut.tv_usec = Wait % 1000;
>
>So "Wait" is in milli-seconds? That doesn't look correct, then:)
>
>        TOut.tv_sec = Wait / 1000;
>        TOut.tv_usec = (Wait % 1000) * 1000;

Sure you're right, but this is a thing that I do not understand. I made a 
function GetTickCount to emulate Window's one based on gettimeofday and see 
that milliseconds on timeval structure can have values up to 999999 when I 
expect to found a maximum value of 999 as there are only 1000 milliseconds in 
a second.

>>       if ( select ( FD_SETSIZE, &readfs, NULL, NULL, &TOut ) ) {

>That's most probably wrong. "FD_SETSIZE" should be "HND + 1". ...and the
>"if" should fire like "if (select (...) > 0)"

Ok, I've tried some different values, I'll use only HND+1 from now.

>This could hand because you didn't select() on HND *before* writing to
>it.

You're right. I've fixed this. 

>>       if ( ! select ( FD_SETSIZE, NULL, &writefs, NULL, &TOut ) ) {
>>               perror ( "Timeout waiting on CommWriteChar");
>>               return 0;
>>       }

>select() checks if the next access won't hand (but may return
>successfull or with an error instead). It doesn't make much sense to do
>that *after* having something written down there:)

>>       return ( bcount );
>> }

>Btw: return isn't a function. It's return value doesn't need an own pair
>of parentheses.

I usually forget this, but I think this makes no efective difference and the 
code generated by the compiler is the same and I feel more comfortable using 
them.

I've done this changes, that I've no doubt that are needed, but I continue 
having the same problems as described in my previous e-mail.

Thanks a lot.

-- 
Francisco M. Marzoa Alonso
Responsable de Software - Softrónica S.A.
http://www.softronica.org/
C/Herrerías, 14 - 28760 Tres Cantos (Madrid)
tfno. +34 918 038 600  fax. +34 918 032 297
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^ permalink raw reply	[flat|nested] 51+ messages in thread