diff --git a/cfg/std.cfg b/cfg/std.cfg
index b70d9080d..09d553b66 100644
--- a/cfg/std.cfg
+++ b/cfg/std.cfg
@@ -6540,7 +6540,9 @@ The obsolete function 'gets' is called. With 'gets' you'll get a buffer overrun
   <podtype name="lconv"/>
   <podtype name="sig_atomic_t"/>
   <podtype name="va_list"/>
-  <podtype name="ptrdiff_t"/>
+  <!-- http://en.cppreference.com/w/c/types/ptrdiff_t -->
+  <!-- http://en.cppreference.com/w/cpp/types/ptrdiff_t-->
+  <podtype name="ptrdiff_t,std::ptrdiff_t" sign="s"/>
   <podtype name="max_align_t"/>
   <podtype name="nullptr_t"/>
   <podtype name="fpos_t"/>