Trent Mick <trentm@activestate.com>: The common technique for printing out a pointer has been to cast to a long and use the "%lx" printf modifier. This is incorrect on Win64 where casting to a long truncates the pointer. The "%p" formatter should be used instead. The problem as stated by Tim: > Unfortunately, the C committee refused to define what %p conversion "looks > like" -- they explicitly allowed it to be implementation-defined. Older > versions of Microsoft C even stuck a colon in the middle of the address (in > the days of segment+offset addressing)! The result is that the hex value of a pointer will maybe/maybe not have a 0x prepended to it. Notes on the patch: There are two main classes of changes: - in the various repr() functions that print out pointers - debugging printf's in the various thread_*.h files (these are why the patch is large) Closes SourceForge patch #100505.

--- a/Objects/floatobject.c	Fri Jun 30 14:58:20 2000 +0000
+++ b/Objects/floatobject.c	Fri Jun 30 15:01:00 2000 +0000
@@ -806,8 +806,8 @@
 					char buf[100];
 					PyFloat_AsString(buf, p);
 					fprintf(stderr,
-			     "#   <float at %lx, refcnt=%d, val=%s>\n",
-						(long)p, p->ob_refcnt, buf);
+			     "#   <float at %p, refcnt=%d, val=%s>\n",
+						p, p->ob_refcnt, buf);
 				}
 			}
 			list = list->next;