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Introduced a Py_IS_NAN macro, which probably works on the major platforms

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today.  pyconfig.h can override it if not, and can also override
Py_IS_INFINITY now.  Py_IS_NAN and Py_IS_INFINITY are overridden now
for Microsoft compilers, using efficient MS-specific spellings.
This commit is contained in:
Tim Peters 2004-09-23 19:11:32 +00:00
parent 307fa78107
commit 862f0593d8
3 changed files with 26 additions and 3 deletions
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19
Include/pyport.h
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@ -219,14 +219,29 @@ extern "C" {
#define Py_SAFE_DOWNCAST(VALUE, WIDE, NARROW) (NARROW)(VALUE)
#endif
/* Py_IS_NAN(X)
* Return 1 if float or double arg is a NaN, else 0.
* Caution:
* X is evaluated more than once.
* This may not work on all platforms. Each platform has *some*
* way to spell this, though -- override in pyconfig.h if you have
* a platform where it doesn't work.
*/
#ifndef Py_IS_NAN
#define Py_IS_NAN(X) ((X) != (X))
#endif
/* Py_IS_INFINITY(X)
* Return 1 if float or double arg is an infinity, else 0.
* Caution:
* X is evaluated more than once.
* This implementation may set the underflow flag if |X| is very small;
* it really can't be implemented correctly (& easily) before C99.
* Override in pyconfig.h if you have a better spelling on your platform.
*/
#ifndef Py_IS_INFINITY
#define Py_IS_INFINITY(X) ((X) && (X)*0.5 == (X))
#endif
/* HUGE_VAL is supposed to expand to a positive double infinity. Python
* uses Py_HUGE_VAL instead because some platforms are broken in this
@ -257,12 +272,12 @@ extern "C" {
* Some platforms have better way to spell this, so expect some #ifdef'ery.
*
* OpenBSD uses 'isinf()' because a compiler bug on that platform causes
* the longer macro version to be mis-compiled. This isn't optimal, and
* the longer macro version to be mis-compiled. This isn't optimal, and
* should be removed once a newer compiler is available on that platform.
* The system that had the failure was running OpenBSD 3.2 on Intel, with
* gcc 2.95.3.
*
* According to Tim's checkin, the FreeBSD systems use isinf() to work
* According to Tim's checkin, the FreeBSD systems use isinf() to work
* around a FPE bug on that platform.
*/
#if defined(__FreeBSD__) || defined(__OpenBSD__)