diff --git a/Texassemble/texassemble.cpp b/Texassemble/texassemble.cpp
index e7b344b..6692b0b 100644
--- a/Texassemble/texassemble.cpp
+++ b/Texassemble/texassemble.cpp
@@ -32,8 +32,11 @@ enum OPTIONS    // Note: dwOptions below assumes 32 or less options.
     OPT_USE_DX10,
     OPT_NOLOGO,
     OPT_SEPALPHA,
+    OPT_MAX
 };
 
+static_assert( OPT_MAX <= 32, "dwOptions is a DWORD bitfield" );
+
 struct SConversion
 {
     WCHAR szSrc [MAX_PATH];