1 files changed, 1 insertions, 1 deletions
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c b/mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c
index 999bd6328..03846cd50 100755
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c
@@ -45,7 +45,7 @@ build_path(mrb_state *mrb, const char *dir, const char *base)
   len = strlen(base) + 1;
 
   if (strcmp(dir, ".")) {
-    len += strlen(dir) + strlen("/");
+    len += strlen(dir) + sizeof("/") - 1;
   }
 
   path = mrb_malloc(mrb, len);