+--- wmctrl-1.07.orig/main.c
++++ wmctrl-1.07/main.c
+@@ -1425,6 +1425,16 @@
+ *
+ * long_length = Specifies the length in 32-bit multiples of the
+ * data to be retrieved.
++ *
++ * NOTE: see
++ * http://mail.gnome.org/archives/wm-spec-list/2003-March/msg00067.html
++ * In particular:
++ *
++ * When the X window system was ported to 64-bit architectures, a
++ * rather peculiar design decision was made. 32-bit quantities such
++ * as Window IDs, atoms, etc, were kept as longs in the client side
++ * APIs, even when long was changed to 64 bits.
++ *
+ */
+ if (XGetWindowProperty(disp, win, xa_prop_name, 0, MAX_PROPERTY_VALUE_LEN / 4, False,
+ xa_prop_type, &xa_ret_type, &ret_format,
+@@ -1441,6 +1451,8 @@
+
+ /* null terminate the result to make string handling easier */
+ tmp_size = (ret_format / 8) * ret_nitems;
++ /* Correct 64 Architecture implementation of 32 bit data */
++ if(ret_format==32) tmp_size *= sizeof(long)/4;
+ ret = g_malloc(tmp_size + 1);
+ memcpy(ret, ret_prop, tmp_size);
+ ret[tmp_size] = '\0';