--- a/plugin_netinfo.c
+++ b/plugin_netinfo.c
@@ -264,7 +264,7 @@ static void my_netmask_short(RESULT * re
     sin = get_netmask(arg1);
     if (NULL != sin) {
 	logval = (long double) (get_netmask(arg1)->sin_addr.s_addr);
-	netlen = (int) rint(log2l(logval) / log2l(2.0));
+	netlen = (int) rint(log2f(logval) / log2f(2.0));
 	qprintf(value, sizeof(value), "/%d", netlen);
     } else {
 	qprintf(value, sizeof(value), "/?");
