[Python-checkins] r64349 - python/trunk/Modules/mathmodule.c

[mark.dickinson]

Author: mark.dickinson
Date: Tue Jun 17 23:16:55 2008
New Revision: 64349

Log:
Issue 3118: make test_math pass on Ubuntu/ia64.  exp(-745.0) was raising 
OverflowError incorrectly on this platform, presumably as a result of 
the libm setting errno = ERANGE for this call.


Modified:
   python/trunk/Modules/mathmodule.c

Modified: python/trunk/Modules/mathmodule.c
==============================================================================
--- python/trunk/Modules/mathmodule.c	(original)
+++ python/trunk/Modules/mathmodule.c	Tue Jun 17 23:16:55 2008
@@ -82,12 +82,17 @@
 		 * should return a zero on underflow, and +- HUGE_VAL on
 		 * overflow, so testing the result for zero suffices to
 		 * distinguish the cases).
+		 *
+		 * On some platforms (Ubuntu/ia64) it seems that errno can be
+		 * set to ERANGE for subnormal results that do *not* underflow
+		 * to zero.  So to be safe, we'll ignore ERANGE whenever the
+		 * function result is less than one in absolute value.
 		 */
-		if (x)
+		if (fabs(x) < 1.0)
+			result = 0;
+		else
 			PyErr_SetString(PyExc_OverflowError,
 					"math range error");
-		else
-			result = 0;
 	}
 	else
                 /* Unexpected math error */