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/funcobject.c	Fri Jun 30 14:58:20 2000 +0000
+++ b/Objects/funcobject.c	Fri Jun 30 15:01:00 2000 +0000
@@ -202,11 +202,11 @@
 {
 	char buf[140];
 	if (op->func_name == Py_None)
-		sprintf(buf, "<anonymous function at %lx>", (long)op);
+		sprintf(buf, "<anonymous function at %p>", op);
 	else
-		sprintf(buf, "<function %.100s at %lx>",
+		sprintf(buf, "<function %.100s at %p>",
 			PyString_AsString(op->func_name),
-			(long)op);
+			op);
 	return PyString_FromString(buf);
 }