ITK  4.9.0
Insight Segmentation and Registration Toolkit
itkStaticAssert.h
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3  * Copyright Insight Software Consortium
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5  * Licensed under the Apache License, Version 2.0 (the "License");
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18 
19 #ifndef itkStaticAssert_h
20 #define itkStaticAssert_h
21 
22 #include "itkMacro.h"
23 
24 #if defined(ITK_HAS_CXX11_STATIC_ASSERT)
25 // Use the C++11 static_assert if available
26 
35 # define itkStaticAssert(expr, str) static_assert(expr, str)
36 #elif defined(__GNUC__) && ((__GNUC__ * 100) + __GNUC_MINOR__ ) >= 403 && !defined(__clang__) && !defined( __INTEL_COMPILER )
37 // GCC 4.3 is enough for this trick
38 // But it restricts the static assertion to non global contexts (-> functions)
39 # define itkStaticAssert(expr,str) \
40  ({extern int __attribute__((error(str))) StaticAssertFailure(); \
41  ((void)((expr) ? 0: StaticAssertFailure()), 0); \
42  })
43 #else
44 // Usual trick (boost, clang, ...), but it will loose the error message on the
45 // way
46 # define ITK_JOIN(X,Y) ITK_DO_JOIN(X,Y)
47 # define ITK_DO_JOIN(X,Y) ITK_DO_JOIN2(X,Y)
48 # define ITK_DO_JOIN2(X,Y) X##Y
49 
50 
51 namespace itk {
53 
57 template <bool V> struct StaticAssertFailure;
58 template <> struct StaticAssertFailure<true>{};
60 } // itk namespace
61 
62 # define itkStaticAssert(expr,str) \
63  enum { ITK_JOIN(static_assert_typedef, __LINE__) = sizeof(itk::StaticAssertFailure<((expr) == 0 ? false : true)>) };
64 #endif
65 
66 #endif // itkStaticAssert_h