--- pyblock-0.53/dm.c.orig	2011-12-08 21:02:03.000000000 +0100
+++ pyblock-0.53/dm.c	2017-03-06 19:06:36.925597603 +0100
@@ -17,6 +17,7 @@
  */
 
 #define _GNU_SOURCE
+#include <sys/sysmacros.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -645,7 +646,7 @@
 
 	rc = pydm_init_table((PydmTableObject *)self, start, size,
 			type, params);
-	if (!rc < 0) {
+	if (rc >= 0) {
 		Py_DECREF(self);
 		return NULL;
 	}