diff --git a/common/environment.c b/common/environment.c
index 0eb7e6b..e5f24ec 100644
--- a/common/environment.c
+++ b/common/environment.c
@@ -109,7 +109,7 @@
 	struct action_data data;
 	void *buf = NULL;
 
-	data.writep = 0;
+	data.writep = NULL;
 	data.base = dirname;
 
 	/* first pass: calculate size */