diff --git a/common/env.c b/common/env.c
index edaf388..f81bd46 100644
--- a/common/env.c
+++ b/common/env.c
@@ -137,7 +137,7 @@
 	const char *val;
 
 	if (strchr(name, '.')) {
-		const char *ret = 0;
+		const char *ret = NULL;
 		char *devstr = strdup(name);
 		char *par = strchr(devstr, '.');
 		struct device_d *dev;