GNAT.Sockets: Timeval_Duration is in milliseconds?

GNAT.Sockets: Timeval_Duration is in milliseconds?

[gpriv]

Hello,

I find it somewhat misleading that Timeout values use different scale
than Ada duration while share that type (not Ada way).  Is there a
purpose in that (other than direct translation in socket library).  It
does cost some headache to figure that out and it would be more
appropriate in Ada style to make a new type for timeouts or scale it
back to seconds.  Anyone would agree?

George

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Simon Wright]

gpriv@axonx.com writes:

> I find it somewhat misleading that Timeout values use different scale
> than Ada duration while share that type (not Ada way).  Is there a
> purpose in that (other than direct translation in socket library).  It
> does cost some headache to figure that out and it would be more
> appropriate in Ada style to make a new type for timeouts or scale it
> back to seconds.  Anyone would agree?

GNAT GPL 2006[1] agrees with you! from GNAT.Sockets,

   --  Timeval_Duration is a subtype of Standard.Duration because the full
   --  range of Standard.Duration cannot be represented in the equivalent C
   --  structure. Moreover, negative values are not allowed to avoid system
   --  incompatibilities.

   Immediate : constant := 0.0;
   Forever   : constant := Duration (Integer'Last) * 1.0;

   subtype Timeval_Duration is Duration range Immediate .. Forever;

[1] No GNAT GPL 2007 for Mac OS X :-(

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[gpriv]

On Dec 8, 5:11 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
> gp...@axonx.com writes:
> > I find it somewhat misleading that Timeout values use different scale
> > than Ada duration while share that type (not Ada way).  Is there a
> > purpose in that (other than direct translation in socket library).  It
> > does cost some headache to figure that out and it would be more
> > appropriate in Ada style to make a new type for timeouts or scale it
> > back to seconds.  Anyone would agree?
>
> GNAT GPL 2006[1] agrees with you! from GNAT.Sockets,
>
>    --  Timeval_Duration is a subtype of Standard.Duration because the full
>    --  range of Standard.Duration cannot be represented in the equivalent C
>    --  structure. Moreover, negative values are not allowed to avoid system
>    --  incompatibilities.
>
>    Immediate : constant := 0.0;
>    Forever   : constant := Duration (Integer'Last) * 1.0;
>
>    subtype Timeval_Duration is Duration range Immediate .. Forever;
>
> [1] No GNAT GPL 2007 for Mac OS X :-(

But that was precisely my point to rather make a new type instead of
subtyping, since scales are totally different.  But that is subjective
I guess.

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[tmoran]

> But that was precisely my point to rather make a new type instead of
> subtyping, since scales are totally different.  But that is subjective
> I guess.

  The Ada 95 LRM 9.6(7) says
"...; a value of type Duration is used to represent the length of
an interval of time, expressed in seconds."

It would be bad practice to use a value of type Duration to represent,
say, the number of gallons of gasoline remaining, and it would be even
worse, because even more confusing, to use it to represent a number
of milliseconds.

>>    Forever   : constant := Duration (Integer'Last) * 1.0;
Is that legal Ada?

Something like
   Forever : constant := Integer'last * 1.0;
or
   Forever : constant Duration := Integer'last * 1.0;
or
   Forever : constant Duration := Duration(Integer'last);
would seem preferable.

(It should probably use Interfaces.C.Int'Last instead of Integer'Last,
and if Interfaces.C.Int is 64 bits that would probably give a compile
time warning.)

>    --  Timeval_Duration is a subtype of Standard.Duration because the full
>    --  range of Standard.Duration cannot be represented in the equivalent C
>    --  structure.
>...
>    Forever   : constant := Duration (Integer'Last) * 1.0;
>
>    subtype Timeval_Duration is Duration range Immediate .. Forever;

If the code is going to multiply by 1000 to convert milliseconds to integers
to put into the C structure, then of course it should be
     Forever : constant Duration := Duration(Integer'last)/1000;

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Dmitry A. Kazakov]

On Sat, 08 Dec 2007 19:45:53 -0600, tmoran@acm.org wrote:

>   The Ada 95 LRM 9.6(7) says
> "...; a value of type Duration is used to represent the length of
> an interval of time, expressed in seconds."
> 
> It would be bad practice to use a value of type Duration to represent,
> say, the number of gallons of gasoline remaining, and it would be even
> worse, because even more confusing, to use it to represent a number
> of milliseconds.

Sorry but this makes no sense. The physical entity being measured is
duration T. Gallon is a measure of volume L**3. Clearly T /= L**3. As for
seconds, milliseconds, years, centuries etc, all they fall under the
category T (duration). They are numbers expressing the *same* physical
entity. It is rather instructive to use the same type for them when
possible.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Gautier]

Dmitry A. Kazakov wrote:
> On Sat, 08 Dec 2007 19:45:53 -0600, tmoran@acm.org wrote:
> 
>>   The Ada 95 LRM 9.6(7) says
>> "...; a value of type Duration is used to represent the length of
>> an interval of time, expressed in seconds."
>>
>> It would be bad practice to use a value of type Duration to represent,
>> say, the number of gallons of gasoline remaining, and it would be even
>> worse, because even more confusing, to use it to represent a number
>> of milliseconds.
> 
> Sorry but this makes no sense. The physical entity being measured is
> duration T. Gallon is a measure of volume L**3. Clearly T /= L**3.

I think it Tom's point: it is so absurd that it is less likely to be mixed.

> As for seconds, milliseconds, years, centuries etc, all they fall under the
> category T (duration). They are numbers expressing the *same* physical
> entity.

Not exactly: the unit for Duration is a second, not a millisecond. I guess it's 
why it is not a floating type, but a fixed one. The SI unit for time is the 
second, not the millisecond; for weight it is the kilogram, not the gram. If 
parts of your program think that a second is worth 1000.0 with type Duration and 
others think that it is 1.0, you are in trouble - imagine a delay statement that 
controls the opening of a door in a space station! HAL, please!
______________________________________________________________
Gautier         -- http://www.mysunrise.ch/users/gdm/index.htm
Ada programming -- http://www.mysunrise.ch/users/gdm/gsoft.htm

NB: For a direct answer, e-mail address on the Web site!

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Dmitry A. Kazakov]

On Sun, 09 Dec 2007 13:50:08 +0100, Gautier wrote:

> Dmitry A. Kazakov wrote:
>> On Sat, 08 Dec 2007 19:45:53 -0600, tmoran@acm.org wrote:
>> 
>>>   The Ada 95 LRM 9.6(7) says
>>> "...; a value of type Duration is used to represent the length of
>>> an interval of time, expressed in seconds."
>>>
>>> It would be bad practice to use a value of type Duration to represent,
>>> say, the number of gallons of gasoline remaining, and it would be even
>>> worse, because even more confusing, to use it to represent a number
>>> of milliseconds.
>> 
>> Sorry but this makes no sense. The physical entity being measured is
>> duration T. Gallon is a measure of volume L**3. Clearly T /= L**3.
> 
> I think it Tom's point: it is so absurd that it is less likely to be mixed.

But seconds and millisecond can be freely mixed. 1ms + 1s = 1.001s =
1001ms.

>> As for seconds, milliseconds, years, centuries etc, all they fall under the
>> category T (duration). They are numbers expressing the *same* physical
>> entity.
> 
> Not exactly: the unit for Duration is a second, not a millisecond.

The point is that the thing measured is duration, not seconds or
milliseconds.

> I guess it's why it is not a floating type, but a fixed one.

? I never heard that duration were a subject of quantization. In any case
it would be far smaller than 1ms. The choice of numerical model is IMO an
implementation issue.

> The SI unit for time is the 
> second, not the millisecond; for weight it is the kilogram, not the gram. If 
> parts of your program think that a second is worth 1000.0 with type Duration and 
> others think that it is 1.0, you are in trouble - imagine a delay statement that 
> controls the opening of a door in a space station! HAL, please!

Exactly my point, this is why one should use Ada's type Duration. There
cannot be any reason to introduce another duration type other than on
implementation grounds.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Martin Krischik]

Dmitry A. Kazakov wrote:

> ? I never heard that duration were a subject of quantization.

You have not read enough articles on quantum physics then:

http://en.wikipedia.org/wiki/Planck_time

>  In any case it would be far smaller than 1ms.

indeed: 5.4 * 10 ** -44

Martin
-- 
mailto://krischik@users.sourceforge.net
Ada programming at: http://ada.krischik.com

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Dmitry A. Kazakov]

On Sun, 09 Dec 2007 15:59:45 +0100, Martin Krischik wrote:

> Dmitry A. Kazakov wrote:
> 
>> ? I never heard that duration were a subject of quantization.
> 
> You have not read enough articles on quantum physics then:

That's for sure! (:-))

> http://en.wikipedia.org/wiki/Planck_time
> 
>>  In any case it would be far smaller than 1ms.
> 
> indeed: 5.4 * 10 ** -44

I see, the smallest distance + maximal speed gives a duration quantum.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[gpriv]

On Dec 9, 4:33 am, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> On Sat, 08 Dec 2007 19:45:53 -0600, tmo...@acm.org wrote:
> >   The Ada 95 LRM 9.6(7) says
> > "...; a value of type Duration is used to represent the length of
> > an interval of time, expressed in seconds."
>
> > It would be bad practice to use a value of type Duration to represent,
> > say, the number of gallons of gasoline remaining, and it would be even
> > worse, because even more confusing, to use it to represent a number
> > of milliseconds.
>
> Sorry but this makes no sense. The physical entity being measured is
> duration T. Gallon is a measure of volume L**3. Clearly T /= L**3. As for
> seconds, milliseconds, years, centuries etc, all they fall under the
> category T (duration). They are numbers expressing the *same* physical
> entity. It is rather instructive to use the same type for them when
> possible.
>
> --
> Regards,
> Dmitry A. Kazakovhttp://www.dmitry-kazakov.de

Conceptually you're right, but many annoying bugs are introduced by
assuming wrong scale when using same entities (feet/meter, T(K)/t(C),
X/Y/Z coordinates, etc.) In order to make the language work for you
one should go with different types.  My favorite is X,Y,Z coordinates:
all measure distance but misinterpreting those may case a trouble.  So
by introducing the new types for each plus one direction-less Distance
type will be good safety measure while all three are distance
entities.

Regards,
George Privalov.

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Dmitry A. Kazakov]

On Sun, 9 Dec 2007 07:55:02 -0800 (PST), gpriv@axonx.com wrote:

> On Dec 9, 4:33 am, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
> wrote:
>> On Sat, 08 Dec 2007 19:45:53 -0600, tmo...@acm.org wrote:
>>>   The Ada 95 LRM 9.6(7) says
>>> "...; a value of type Duration is used to represent the length of
>>> an interval of time, expressed in seconds."
>>
>>> It would be bad practice to use a value of type Duration to represent,
>>> say, the number of gallons of gasoline remaining, and it would be even
>>> worse, because even more confusing, to use it to represent a number
>>> of milliseconds.
>>
>> Sorry but this makes no sense. The physical entity being measured is
>> duration T. Gallon is a measure of volume L**3. Clearly T /= L**3. As for
>> seconds, milliseconds, years, centuries etc, all they fall under the
>> category T (duration). They are numbers expressing the *same* physical
>> entity. It is rather instructive to use the same type for them when
>> possible.
> 
> Conceptually you're right, but many annoying bugs are introduced by
> assuming wrong scale when using same entities (feet/meter, T(K)/t(C),
> X/Y/Z coordinates, etc.) In order to make the language work for you
> one should go with different types.  My favorite is X,Y,Z coordinates:
> all measure distance but misinterpreting those may case a trouble.  So
> by introducing the new types for each plus one direction-less Distance
> type will be good safety measure while all three are distance
> entities.

It makes a lot of sense to use distinct types for horizontal and vertical
distances as long no rotation operation is used. I do it too. Similarly it
makes even more sense to distinguish screen coordinates and ones relative
to some window. The same could be true for durations when applied to
different, unsynchronized epochs, for instance.

But all this just does not apply to the case at hand. Because that deals
with exactly the same physical entity as the delay statement does.
Therefore using a separate type is just a bad design that slavishly follows
OS APIs.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Simon Wright]

gpriv@axonx.com writes:

> On Dec 8, 5:11 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
>> gp...@axonx.com writes:
>> > I find it somewhat misleading that Timeout values use different scale
>> > than Ada duration while share that type (not Ada way).  Is there a
>> > purpose in that (other than direct translation in socket library).  It
>> > does cost some headache to figure that out and it would be more
>> > appropriate in Ada style to make a new type for timeouts or scale it
>> > back to seconds.  Anyone would agree?
>>
>> GNAT GPL 2006[1] agrees with you! from GNAT.Sockets,
>>
>>    --  Timeval_Duration is a subtype of Standard.Duration because the full
>>    --  range of Standard.Duration cannot be represented in the equivalent C
>>    --  structure. Moreover, negative values are not allowed to avoid system
>>    --  incompatibilities.
>>
>>    Immediate : constant := 0.0;
>>    Forever   : constant := Duration (Integer'Last) * 1.0;
>>
>>    subtype Timeval_Duration is Duration range Immediate .. Forever;
>>
>> [1] No GNAT GPL 2007 for Mac OS X :-(
>
> But that was precisely my point to rather make a new type instead of
> subtyping, since scales are totally different.  But that is subjective
> I guess.

Oh. I don't understand why you think that milliseconds are involved at
all?

*If* a Timeval_Duration was in units of milliseconds you would be
 completely right. But it is in seconds, just as it should be.

If you look at GNAT.Sockets'Body you'll find

   function To_Timeval (Val : Timeval_Duration) return Timeval is
      S  : time_t;
      uS : suseconds_t;

   begin
      --  If zero, set result as zero (otherwise it gets rounded down to -1)

      if Val = 0.0 then
         S  := 0;
         uS := 0;

      --  Normal case where we do round down

      else
         S  := time_t (Val - 0.5);
         uS := suseconds_t (1_000_000 * (Val - Selector_Duration (S)));
      end if;

      return (S, uS);
   end To_Timeval;

which is pretty clearly based on *seconds*.

(If you wanted to ask what Selector_Duration is doing there -- it's an
unconstrained subtype of Timeval_Duration -- you'd have a point!)

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[gpriv]

On Dec 9, 1:26 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
> gp...@axonx.com writes:
> > On Dec 8, 5:11 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
> >> gp...@axonx.com writes:
> >> > I find it somewhat misleading that Timeout values use different scale
> >> > than Ada duration while share that type (not Ada way).  Is there a
> >> > purpose in that (other than direct translation in socket library).  It
> >> > does cost some headache to figure that out and it would be more
> >> > appropriate in Ada style to make a new type for timeouts or scale it
> >> > back to seconds.  Anyone would agree?
>
> >> GNAT GPL 2006[1] agrees with you! from GNAT.Sockets,
>
> >>    --  Timeval_Duration is a subtype of Standard.Duration because the full
> >>    --  range of Standard.Duration cannot be represented in the equivalent C
> >>    --  structure. Moreover, negative values are not allowed to avoid system
> >>    --  incompatibilities.
>
> >>    Immediate : constant := 0.0;
> >>    Forever   : constant := Duration (Integer'Last) * 1.0;
>
> >>    subtype Timeval_Duration is Duration range Immediate .. Forever;
>
> >> [1] No GNAT GPL 2007 for Mac OS X :-(
>
> > But that was precisely my point to rather make a new type instead of
> > subtyping, since scales are totally different.  But that is subjective
> > I guess.
>
> Oh. I don't understand why you think that milliseconds are involved at
> all?
>
> *If* a Timeval_Duration was in units of milliseconds you would be
>  completely right. But it is in seconds, just as it should be.
>
> If you look at GNAT.Sockets'Body you'll find
>
>    function To_Timeval (Val : Timeval_Duration) return Timeval is
>       S  : time_t;
>       uS : suseconds_t;
>
>    begin
>       --  If zero, set result as zero (otherwise it gets rounded down to -1)
>
>       if Val = 0.0 then
>          S  := 0;
>          uS := 0;
>
>       --  Normal case where we do round down
>
>       else
>          S  := time_t (Val - 0.5);
>          uS := suseconds_t (1_000_000 * (Val - Selector_Duration (S)));
>       end if;
>
>       return (S, uS);
>    end To_Timeval;
>
> which is pretty clearly based on *seconds*.
>
> (If you wanted to ask what Selector_Duration is doing there -- it's an
> unconstrained subtype of Timeval_Duration -- you'd have a point!)

That's very good point, but unfortunately it is not what happening in
real (windows at least).  Setsockoption defines timeouts in
milliseconds:

http://msdn2.microsoft.com/en-us/library/ms740532.aspx

"Sets a timeout, in milliseconds, for blocking receive calls. The
default for this option is zero, which indicates that a receive
operation will not time out. If a blocking receive call times out, the
connection is in an indeterminate state and should be closed."

Here is a fragment from my old code to set the timeout in milliseconds
and it worked:


	void Socket::RecvTimeout(int to)
	{
		int rc = setsockopt(mSock, SOL_SOCKET, SO_RCVTIMEO, (char*) &to,
sizeof(to));
		if (rc == SOCKET_ERROR)
			std::cerr << "Failed socket option" << std::endl;
	}



The confusion comes from crudeness of setsockopt with const char*
being passed as parameter.  So in Gnat.socket case it is passing
structure with second.micosecondsecond part. In windows it may be
simply taking the first value and interpret it as milliseconds.  Haven
checked on Linux yet.

What a mess!

George

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Simon Wright]

gpriv@axonx.com writes:

> http://msdn2.microsoft.com/en-us/library/ms740532.aspx
>
> "Sets a timeout, in milliseconds, for blocking receive calls. The
> default for this option is zero, which indicates that a receive
> operation will not time out. If a blocking receive call times out,
> the connection is in an indeterminate state and should be closed."

So if you are using Windows, Microsoft's decision to screw things up
by using a different socket argument structure from the pre-existing
BSD argument structure means that the current GNAT code indeed works in
milliseconds instead of the seconds it is trying to.

I suppose we have to report this as a bug in GNAT though it would be
much more satisfactory to have Microsoft fix it where it should be
fixed. It could never have been the intention to have the effect you
observe!

Which version of GNAT are you using?

Personally I've never used timeouts -- I've used select() and waited
'forever'.

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[gpriv]

On Dec 9, 5:51 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
> gp...@axonx.com writes:
> >http://msdn2.microsoft.com/en-us/library/ms740532.aspx
>
> > "Sets a timeout, in milliseconds, for blocking receive calls. The
> > default for this option is zero, which indicates that a receive
> > operation will not time out. If a blocking receive call times out,
> > the connection is in an indeterminate state and should be closed."
>
> So if you are using Windows, Microsoft's decision to screw things up
> by using a different socket argument structure from the pre-existing
> BSD argument structure means that the current GNAT code indeed works in
> milliseconds instead of the seconds it is trying to.
>
> I suppose we have to report this as a bug in GNAT though it would be
> much more satisfactory to have Microsoft fix it where it should be
> fixed. It could never have been the intention to have the effect you
> observe!
>
> Which version of GNAT are you using?
>
> Personally I've never used timeouts -- I've used select() and waited
> 'forever'.

Isn't MS always making things "Better" without us even knowing it :-)

I use GPS 4.1.3 (20070913), GNAT GPL 2007 (20070405-41)

I prefer sockets with timeouts since the application is monitoring
many (1..100) "field" devices and it is written around abstract device
interfaces. Sets with only one socket seems to be overcomplication,
besides I am not sure that timeouts there are not screwed-up on
windows either.  Those devices send data at least every second, but
may "die" quietly and unexpectedly and that should be detected in
short order.  Timeout works fine when numbers are right.  It may be
good idea to fix windows version of GNAT though.

Regards,

George

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Simon Wright]

gpriv@axonx.com writes:

> I use GPS 4.1.3 (20070913), GNAT GPL 2007 (20070405-41)
>
> It may be good idea to fix windows version of GNAT though.

GNAT 6.0.1 handles this program properly on Windows XP ..

   with Ada.Calendar;
   with Ada.Text_IO; use Ada.Text_IO;
   with GNAT.Sockets;
   procedure Socket_Times is
      Sel : GNAT.Sockets.Selector_Type;
      R, W : GNAT.Sockets.Socket_Set_Type;
      Stat : GNAT.Sockets.Selector_Status;
      Start, Finish : Ada.Calendar.Time;
      use type Ada.Calendar.Time;
   begin
      GNAT.Sockets.Initialize; 
      GNAT.Sockets.Create_Selector (Sel); 
      Put_Line ("starting..");
      Start := Ada.Calendar.Clock;
      GNAT.Sockets.Check_Selector (Sel, R, W, Stat, 5.0);
      Finish := Ada.Calendar.Clock;
      Put_Line ("..done with " 
                & Stat'Img
                & " after "
                & Duration'Image (Finish - Start));
   end Socket_Times;

(I don't have the output here, but it printed

   ..done with EXPIRED after 5.0001

or thereabouts, same as GPL 2006 on Mac OS X).


Anyone care to try this on other Windows GNAT compiler releases?

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[gpriv]

On Dec 10, 3:06 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
> gp...@axonx.com writes:
> > I use GPS 4.1.3 (20070913), GNAT GPL 2007 (20070405-41)
>
> > It may be good idea to fix windows version of GNAT though.
>
> GNAT 6.0.1 handles this program properly on Windows XP ..
>
>    with Ada.Calendar;
>    with Ada.Text_IO; use Ada.Text_IO;
>    with GNAT.Sockets;
>    procedure Socket_Times is
>       Sel : GNAT.Sockets.Selector_Type;
>       R, W : GNAT.Sockets.Socket_Set_Type;
>       Stat : GNAT.Sockets.Selector_Status;
>       Start, Finish : Ada.Calendar.Time;
>       use type Ada.Calendar.Time;
>    begin
>       GNAT.Sockets.Initialize;
>       GNAT.Sockets.Create_Selector (Sel);
>       Put_Line ("starting..");
>       Start := Ada.Calendar.Clock;
>       GNAT.Sockets.Check_Selector (Sel, R, W, Stat, 5.0);
>       Finish := Ada.Calendar.Clock;
>       Put_Line ("..done with "
>                 & Stat'Img
>                 & " after "
>                 & Duration'Image (Finish - Start));
>    end Socket_Times;
>
> (I don't have the output here, but it printed
>
>    ..done with EXPIRED after 5.0001
>
> or thereabouts, same as GPL 2006 on Mac OS X).
>
> Anyone care to try this on other Windows GNAT compiler releases?

Yep, it worked:

..done with EXPIRED after  4.999302724

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Simon Wright]

gpriv@axonx.com writes:

> Yep, it worked:
>
> ..done with EXPIRED after  4.999302724

So GNAT GPL 2007 handles _this_ call right -- which functionality was
it you had the problem with? Do you have a test case?

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[gpriv]

On Dec 11, 3:33 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
> gp...@axonx.com writes:
> > Yep, it worked:
>
> > ..done with EXPIRED after  4.999302724
>
> So GNAT GPL 2007 handles _this_ call right -- which functionality was
> it you had the problem with? Do you have a test case?


Linux update:

Timeout value is in seconds here. So it is only a Windows problem as
to be expected.

thanx

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Simon Wright]

gpriv@axonx.com writes:

> On Dec 11, 3:33 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
>> gp...@axonx.com writes:
>> > Yep, it worked:
>>
>> > ..done with EXPIRED after  4.999302724
>>
>> So GNAT GPL 2007 handles _this_ call right -- which functionality was
>> it you had the problem with? Do you have a test case?
>
>
> Linux update:
>
> Timeout value is in seconds here. So it is only a Windows problem as
> to be expected.

Looking at http://msdn2.microsoft.com/en-us/library/ms740141.aspx it
turns out that the Windows version of select(2) uses a struct timeval*
-- so not surprising that it behaves as we were expecting. Huh.

--S

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[gpriv]

On Dec 13, 8:13 am, Simon Wright <simon.j.wri...@mac.com> wrote:
> gp...@axonx.com writes:
> > On Dec 11, 3:33 pm, Simon Wright <simon.j.wri...@mac.com> wrote:
> >> gp...@axonx.com writes:
> >> > Yep, it worked:
>
> >> > ..done with EXPIRED after  4.999302724
>
> >> So GNAT GPL 2007 handles _this_ call right -- which functionality was
> >> it you had the problem with? Do you have a test case?
>
> > Linux update:
>
> > Timeout value is in seconds here. So it is only a Windows problem as
> > to be expected.
>
> Looking athttp://msdn2.microsoft.com/en-us/library/ms740141.aspxit
> turns out that the Windows version of select(2) uses a struct timeval*
> -- so not surprising that it behaves as we were expecting. Huh.
>
> --S

Microsoft could fix that problem by checking the size of the parameter
passed to setsockopt without breaking all the software already written
for winsock.

George.

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[tmoran]

> *If* a Timeval_Duration was in units of milliseconds you would be
>  completely right. But it is in seconds, just as it should be.
  So regardless of where it occurs in the program, the statement
T2 := T1 + Duration'(1.0);
will result in T2 being one second later than T1 - it will never
make T2 one millisecond later than T1.
That's a relief.

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Martin Krischik]

Simon Wright wrote:

> [1] No GNAT GPL 2007 for Mac OS X :-(

Why not  join The GNU Ada Project [1] create your own?

Martin

[1] http://gnuada.sf.net
-- 
mailto://krischik@users.sourceforge.net
Ada programming at: http://ada.krischik.com

Re: GNAT.Sockets: Timeval_Duration is in milliseconds?

[Dmitry A. Kazakov]

On Sat, 8 Dec 2007 11:45:34 -0800 (PST), gpriv@axonx.com wrote:

> I find it somewhat misleading that Timeout values use different scale
> than Ada duration while share that type (not Ada way).  Is there a
> purpose in that (other than direct translation in socket library).  It
> does cost some headache to figure that out and it would be more
> appropriate in Ada style to make a new type for timeouts or scale it
> back to seconds.  Anyone would agree?

I do.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de