PyInt_FromSsize_t LONG_MIN and LONG_MAX typecasts needed #49130

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1. lkcl commented on Jan 8, 2009

   

   lkclmannequin

   on Jan 8, 2009

   MannequinAuthor

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   there's probably a better way to do this (or a better reason), but
   LONG_MIN and LONG_MAX end up as the wrong constant types when compiling
   python2.5.2 under wine (don't ask...)

   PyObject *
   PyInt_FromSsize_t(Py_ssize_t ival)
   {
       if ((long)ival >= (long)LONG_MIN && (long)ival <= (long)LONG_MAX)
       {
           return PyInt_FromLong((long)ival);
       }
       return _PyLong_FromSsize_t(ival);
   }
2. mdickinson commented on Jan 8, 2009

   

   mdickinson

   on Jan 8, 2009

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   Interesting. How many of those casts are actually necessary to make
   things work? Have you figured out more precisely why this is failing?
   E.g., is it somehow that LONG_MIN ends up being an unsigned constant?

   It seems to me that a better fix would be to fix LONG_MIN and LONG_MAX
   somewhere in the configuration files; there are bound to be more uses of
   LONG_MIN and LONG_MAX in the source that are going to cause problems.

   P.S. Looking at your python-dev messages, does len([1, 2]) really return
   1L? Not 2L?
3. lkcl commented on Jan 8, 2009

   

   lkclmannequin

   on Jan 8, 2009

   MannequinAuthor

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   oh, duh - 2L not 1L yes you're right :)

   yeh i believe it's likely to be because in PC/pyconfig.h LONG_MAX is
   #defined to 7fffffff not 7fffffffL i'll double-check.

   you're right that would make life a looot easier.
4. lkcl commented on Jan 8, 2009

   

   lkclmannequin

   on Jan 8, 2009

   MannequinAuthor

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   .... hmmm... noo, it's already #defined to 0x7fffffffL in
   both PC/pyconfig.h _and_ in /usr/include/wine/msvcrt/limits.h

   so .... this works (Include/pyports.h)

   #ifdef __WINE__  /* weird: you have to typecast 0x7fffffffL to long */
   #undef LONG_MAX
   #undef LONG_MIN
   #define LONG_MAX ((long)0x7FFFFFFFL)
   #define LONG_MIN ((long)(-LONG_MAX-1))
   #else
   #ifndef LONG_MAX
   #if SIZEOF_LONG == 4
   #define LONG_MAX 0X7FFFFFFFL
   #elif SIZEOF_LONG == 8
   #define LONG_MAX 0X7FFFFFFFFFFFFFFFL
   #else
   #error "could not set LONG_MAX in pyport.h"
   #endif
   #endif
   
   #ifndef LONG_MIN
   #define LONG_MIN (-LONG_MAX-1)
   #endif

   #endif /* __WINE__ */
5. loewis commented on Jan 8, 2009

   

   loewismannequin

   on Jan 8, 2009

   Mannequin

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   I think you should study the preprocessor output to find out what
   LONG_MAX really expands to, at the point where it is used.

   In any case, I'm tempted to close this as "works for me" - 0x7FFFFFFFL
   is definitely a long constant in all compilers I know of.
6. mdickinson commented on Feb 11, 2009

   

   mdickinson

   on Feb 11, 2009

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   It seems likely that this is a wine bug rather than a Python bug.
7. mdickinson

   closed this as completedon Feb 11, 2009
8. ezio-melotti

   transferred this issue fromon Apr 10, 2022