First blush

git-svn-id: svn://svn.code.sf.net/p/loki-lib/code/trunk@6 7ec92016-0320-0410-acc4-a06ded1c099a

static_check.h

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+////////////////////////////////////////////////////////////////////////////////
+// The Loki Library
+// Copyright (c) 2001 by Andrei Alexandrescu
+// This code accompanies the book:
+// Alexandrescu, Andrei. "Modern C++ Design: Generic Programming and Design 
+//     Patterns Applied". Copyright (c) 2001. Addison-Wesley.
+// Permission to use, copy, modify, distribute and sell this software for any 
+//     purpose is hereby granted without fee, provided that the above copyright 
+//     notice appear in all copies and that both that copyright notice and this 
+//     permission notice appear in supporting documentation.
+// The author or Addison-Welsey Longman make no representations about the 
+//     suitability of this software for any purpose. It is provided "as is" 
+//     without express or implied warranty.
+////////////////////////////////////////////////////////////////////////////////
+
+// Last update: February 19, 2001
+
+#ifndef STATIC_CHECK_INC_
+#define STATIC_CHECK_INC_
+
+namespace Loki
+{
+////////////////////////////////////////////////////////////////////////////////
+// Helper structure for the STATIC_CHECK macro
+////////////////////////////////////////////////////////////////////////////////
+
+    template<bool> struct CompileTimeChecker
+    {
+        CompileTimeChecker(...); 
+    };
+
+    template<> struct CompileTimeChecker<false> {};
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// macro STATIC_CHECK
+// Invocation: STATIC_CHECK(expr, id)
+// where:
+// expr is a compile-time integral or pointer expression
+// id is a C++ identifier that does not need to be defined
+// If expr is zero, id will appear in a compile-time error message.
+////////////////////////////////////////////////////////////////////////////////
+
+#define STATIC_CHECK(expr, msg) \
+    {\
+        class ERROR_##msg {}; \
+        (void)sizeof(::Loki::CompileTimeChecker<(expr) != 0>(ERROR_##msg()));\
+    }
+
+#endif // STATIC_CHECK_INC_