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/object.c	Fri Jun 30 14:58:20 2000 +0000
+++ b/Objects/object.c	Fri Jun 30 15:01:00 2000 +0000
@@ -229,12 +229,12 @@
 	}
 	else {
 		if (op->ob_refcnt <= 0)
-			fprintf(fp, "<refcnt %u at %lx>",
-				op->ob_refcnt, (long)op);
+			fprintf(fp, "<refcnt %u at %p>",
+				op->ob_refcnt, op);
 		else if (op->ob_type->tp_print == NULL) {
 			if (op->ob_type->tp_repr == NULL) {
-				fprintf(fp, "<%s object at %lx>",
-					op->ob_type->tp_name, (long)op);
+				fprintf(fp, "<%s object at %p>",
+					op->ob_type->tp_name, op);
 			}
 			else {
 				PyObject *s;
@@ -280,8 +280,8 @@
 		return PyString_FromString("<NULL>");
 	else if (v->ob_type->tp_repr == NULL) {
 		char buf[120];
-		sprintf(buf, "<%.80s object at %lx>",
-			v->ob_type->tp_name, (long)v);
+		sprintf(buf, "<%.80s object at %p>",
+			v->ob_type->tp_name, v);
 		return PyString_FromString(buf);
 	}
 	else {