--- a/ExternalBytes.st	Thu May 10 15:46:42 2018 +0200
+++ b/ExternalBytes.st	Thu May 10 20:26:02 2018 +0200
@@ -690,6 +690,21 @@
     "
 !
 
+pointerAlignment
+    "return the alignement of pointers in structs and unions"
+
+%{  /* NOCONTEXT */
+    struct {
+        char c;
+        void* p;
+    } dummy;
+    RETURN (__mkSmallInteger( (char *)&dummy.p - (char *)&dummy.c ));
+%}
+    "
+     ExternalBytes pointerAlignment
+    "
+!
+
 sizeofDouble
     "return the number of bytes used by the machines native doubles"