[Oorexx-bugs] [ oorexx-Bugs-2207721 ] ObjectToDouble(nan) native API failure on AIX

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Bugs item #2207721, was opened at 2008-10-29 17:40
Message generated for change (Comment added) made by tammer
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Category: APIs
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Mark Miesfeld (miesfeld)
Assigned to: Nobody/Anonymous (nobody)
Summary: ObjectToDouble(nan) native API failure on AIX

Initial Comment:
Hi Rick,

Think I need help with this one too.  Rather than post to the list, I thought I'd open up a bug so you can look at it when you have time.

On AIX, in the CONVERSION.testGroup these types of test cases are failing:

  val = "nan"
  self~assertSame(val, .CONVERSIONTester~TestObjectToDouble(val))

Rather than nan, they are producing +infinity

[failure] [20081029 16:31:13.155443]
 svn:    r3371   Change date: 2008-09-21 06:33:29 +0200
 Test:   TESTDOUBLE03
 Class:  CONVERSION.testGroup
 File:   /daten/svn/ooRexx/test/trunk/ooRexx/API/oo/CONVERSION.testGroup
 Line:   827
 Failed: assertSame
   Expected: [[nan], identityHash="100785925"]
   Actual:   [[-infinity], identityHash="112493565"]

I think it is a difference in the C++ libraries on AIX, maybe coming from here in StringClass.cpp:

    // non numeric, so this could be one of the special cases
    if (strCompare("nan"))
    {
        result = std::numeric_limits<double>::signaling_NaN();
        return true;
    }

But, I'm not sure.  Plus, I don't really know what to do about it even if it is the root cause.  <grin>

I'll attach the log output.

----------------------------------------------------------------------

Comment By: Rainer Tammer (tammer)
Date: 2008-10-30 15:22

Message:
Hello,
ok here is the thing: 

With the following test:

#include <stdio.h>
#include <math.h>
#include <limits>

int main(void)
{

    /* double number = NAN; */
    double number = std::numeric_limits<double>::signaling_NaN();

    if (isnan(number))
    {
        printf(">0\n");
    }
    else if (number == +HUGE_VAL)
    {
      printf("+HUGE_VAL\n");
    }
    else if (number == -HUGE_VAL)
    {
      printf("-HUGE_VAL\n");
    }
    else
    {
        printf("none\n");
    }
    return(0);
}

I get the following results:

Linux SLES9 / 32 Bit
./test
>0

AIX 5.3 32 bit compile on 64 bit OS:

./test
-HUGE_VAL

Bye
  Rainer

----------------------------------------------------------------------

Comment By: Rainer Tammer (tammer)
Date: 2008-10-30 15:15

Message:
Hello,
I am not good the the C++ stuff ... but here is another example:

#include <stdio.h>
#include <math.h>
#include <limits>

int main(void)
{

    /* double number = NAN; */
    double number = std::numeric_limits<double>::signaling_NaN();
    printf("number=%lld\n", number);

    // make a nan value a string value
    if (isnan(number))
    {
        printf(">0\n");
    }
    else if (number == -HUGE_VAL)
    {
      printf("HUGE_VAL");
    }
    else
    {
        printf("no\n");
    }
    return(0);
}

./test_isnan
number=-4503599627370496
HUGE_VAL

Bye
  Rainer


----------------------------------------------------------------------

Comment By: Rainer Tammer (tammer)
Date: 2008-10-30 15:01

Message:
Hello,
on Linux (SLES9 / 32 bit):

./test
number=1074642088
>0

Bye
  Rainer

----------------------------------------------------------------------

Comment By: Rick McGuire (bigrixx)
Date: 2008-10-30 15:00

Message:
I'm not sure I understand what you mean by "where is nan defined ??".  In
that context, "nan" is just the character string "nan".  The
ObjectToDouble() code recognizes that value as special and returns the
value "std::numeric_limits<double>::signaling_NaN()" as a result.  This is
part of the standard C++ standard library.  That's the value you need to be
using in your test program. 

----------------------------------------------------------------------

Comment By: Rainer Tammer (tammer)
Date: 2008-10-30 14:54

Message:
Hello,
in the test you use val = "nan".
where is nan defined ??

this is a little test:

#include <stdio.h>
#include <math.h>

int main(void)
{

    double number = NAN;  /* NAN comes from math.h */
    printf("number=%ld\n");
....
    // make a nan value a string value
    if (isnan(number))
    {
        printf(">0\n");
    }
    else if (number == +HUGE_VAL)
    {
        printf("+infinity\n");
    }
    else if (number == -HUGE_VAL)
    {
        printf("-infinity\n");
    }
    return(0);
}

./test_isnan
number=804399748
>0


Bye
  Rainer

----------------------------------------------------------------------

Comment By: Rick McGuire (bigrixx)
Date: 2008-10-29 17:56

Message:
I see two potential places where things can go wrong, but this most likely
is due to a problem in the C++ libraries.  The first place is where you
noted.  It's possible that std::numeric_limits<double>::signaling_NaN() is
not actually returning a NaN value.  The other place is in
NumberString::newInstanceFromDouble() where the double object is converted
back into a Rexx object.  It is possible that the test for isnan() is
failing, but given that an "==" comparison is always supposed to fail for a
NaN value, the comparison to -HUGE_VAL should not work.  The other
possibility is it made it through all of the if special cases and sprintf()
formatted the value as "-infinity" for us.  Understanding where the
"-infinity" string comes from would help narrow down the real point of
failure. 

----------------------------------------------------------------------

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