diff --git a/Source/utf.cpp b/Source/utf.cpp
index 8d0f8425..7658552a 100644
--- a/Source/utf.cpp
+++ b/Source/utf.cpp
@@ -32,6 +32,9 @@ bool StrSetUTF16LE(tstring&dest, const void*src)
   if (!cec.Initialize(-1,NStreamEncoding::UTF16LE)) return false;
   src = (const void*) cec.Convert(src);
   if (!src) return false;
+#endif
+#ifdef C_ASSERT
+  C_ASSERT(sizeof(tstring::value_type) >= sizeof(wchar_t));
 #endif
   try { dest = (wchar_t*) src; } catch(...) { return false; }
   return true;