Stop trying to cater to platforms with a broken HUGE_VAL definition. It

breaks other platforms (in this case, the hack for broken Cray systems in
turn caused failure on a Mac system broken in a different way).

2 files changed, 25 insertions, 12 deletions

diff --git a/Include/pyport.h b/Include/pyport.h
index 5c3e0a9..3f0923f 100644
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -229,19 +229,14 @@ extern "C" {
  */
 #define Py_IS_INFINITY(X) ((X) && (X)*0.5 == (X))
 
-/* According to
- * http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
- * on some Cray systems HUGE_VAL is incorrectly (according to the C std)
- * defined to be the largest positive finite rather than infinity.  We need
- * the std-conforming infinity meaning (provided the platform has one!).
- *
- * Then, according to a bug report on SourceForge, defining Py_HUGE_VAL as
- * INFINITY caused internal compiler errors under BeOS using some version
- * of gcc.  Explicitly casting INFINITY to double made that problem go away.
+/* HUGE_VAL is supposed to expand to a positive double infinity.  Python
+ * uses Py_HUGE_VAL instead because some platforms are broken in this
+ * respect.  We used to embed code in pyport.h to try to worm around that,
+ * but different platforms are broken in conflicting ways.  If you're on
+ * a platform where HUGE_VAL is defined incorrectly, fiddle your Python
+ * config to #define Py_HUGE_VAL to something that works on your platform.
  */
-#ifdef INFINITY
-#define Py_HUGE_VAL ((double)INFINITY)
-#else
+#ifndef Py_HUGE_VAL
 #define Py_HUGE_VAL HUGE_VAL
 #endif
 
diff --git a/Misc/NEWS b/Misc/NEWS
index defbc47..c8bda83 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -289,6 +289,24 @@ Tools/Demos
 
 Build
 
+- Accoring to Annex F of the current C standard,
+
+    The Standard C macro HUGE_VAL and its float and long double analogs,
+    HUGE_VALF and HUGE_VALL, expand to expressions whose values are
+    positive infinities.
+
+  Python only uses the double HUGE_VAL, and only to #define its own symbol
+  Py_HUGE_VAL.  Some platforms have incorrect definitions for HUGE_VAL.
+  pyport.h used to try to worm around that, but the workarounds triggered
+  other bugs on other platforms, so we gave up.  If your platform defines
+  HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
+  that works on your platform.  The only instance of this I'm sure about
+  is on an unknown subset of Cray systems, described here:
+
+  http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
+
+  Presumably 2.3a1 breaks such systems.  If anyone uses such a system, help!
+
 - The configure option --without-doc-strings can be used to remove the
   doc strings from the builtin functions and modules; this reduces the
   size of the executable.