--- a/src/pkg_columnizer.cc
+++ b/src/pkg_columnizer.cc
@@ -397,8 +397,8 @@
       break;
     case diskusage:
       {
-	size_t bufsize = 256;
-	char buf[bufsize] = "";
+	const size_t bufsize = 256;
+	char buf[bufsize] = {};
 	if (apt_cache_file && ((*apt_cache_file)->UsrSize() != 0))
 	  {
 	    char sign = ((*apt_cache_file)->UsrSize() > 0) ? '+' : '-';
