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Use variadic macros in static assert to make use easier.

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Add warning suppression for GCC.
Minor doc fix.
Fixes #5810.
Fixes #7242.
Fixes #7966.

[SVN r82886]
This commit is contained in:
John Maddock
2013-02-14 18:31:33 +00:00
parent ce9e800db8
commit 2993231dad
3 changed files with 62 additions and 16 deletions
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8
doc/static_assert.qbk
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@ -151,10 +151,10 @@ using something like this:
class myclass class myclass
{ {
private: private:
BOOST_STATIC_ASSERT((std::numeric_limits<UnsignedInt>::digits >= 16) BOOST_STATIC_ASSERT_MSG(std::numeric_limits<UnsignedInt>::is_specialized, "myclass can only be specialized for types with numeric_limits support.");
&& std::numeric_limits<UnsignedInt>::is_specialized BOOST_STATIC_ASSERT_MSG(std::numeric_limits<UnsignedInt>::digits >= 16, "Template argument UnsignedInt must have at least 16 bits precision.")
&& std::numeric_limits<UnsignedInt>::is_integer BOOST_STATIC_ASSERT_MSG(std::numeric_limits<UnsignedInt>::is_integer, "Template argument UnsignedInt must be an integer.");
&& !std::numeric_limits<UnsignedInt>::is_signed); BOOST_STATIC_ASSERT_MSG(!std::numeric_limits<UnsignedInt>::is_signed, "Template argument UnsignedInt must not be signed.");
public: public:
/* details here */ /* details here */
}; };

60
include/boost/static_assert.hpp
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@ -18,9 +18,13 @@
#include <boost/detail/workaround.hpp> #include <boost/detail/workaround.hpp>
#ifndef BOOST_NO_CXX11_STATIC_ASSERT #ifndef BOOST_NO_CXX11_STATIC_ASSERT
# define BOOST_STATIC_ASSERT_MSG( B, Msg ) static_assert(B, Msg) # ifndef BOOST_NO_CXX11_VARIADIC_MACROS
# define BOOST_STATIC_ASSERT_MSG( ... ) static_assert(__VA_ARGS__)
# else
# define BOOST_STATIC_ASSERT_MSG( ... ) static_assert(__VA_ARGS__)
# endif
#else #else
# define BOOST_STATIC_ASSERT_MSG( B, Msg ) BOOST_STATIC_ASSERT( B ) # define BOOST_STATIC_ASSERT_MSG( B, Msg ) BOOST_STATIC_ASSERT( B )
#endif #endif
#ifdef __BORLANDC__ #ifdef __BORLANDC__
@ -39,13 +43,33 @@
// then enable this: // then enable this:
// //
#if defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4))) #if defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4)))
# define BOOST_STATIC_ASSERT_BOOL_CAST( x ) ((x) == 0 ? false : true) # ifndef BOOST_NO_CXX11_VARIADIC_MACROS
# define BOOST_STATIC_ASSERT_BOOL_CAST( ... ) ((__VA_ARGS__) == 0 ? false : true)
# else
# define BOOST_STATIC_ASSERT_BOOL_CAST( x ) ((x) == 0 ? false : true)
# endif
#else #else
# define BOOST_STATIC_ASSERT_BOOL_CAST(x) (bool)(x) # ifndef BOOST_NO_CXX11_VARIADIC_MACROS
# define BOOST_STATIC_ASSERT_BOOL_CAST( ... ) (bool)(__VA_ARGS__)
# else
# define BOOST_STATIC_ASSERT_BOOL_CAST(x) (bool)(x)
# endif
#endif
//
// If the compiler warns about unused typedefs then enable this:
//
#if defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)))
# define BOOST_STATIC_ASSERT_UNUSED_ATTRIBUTE __attribute__((unused))
#else
# define BOOST_STATIC_ASSERT_UNUSED_ATTRIBUTE
#endif #endif
#ifndef BOOST_NO_CXX11_STATIC_ASSERT #ifndef BOOST_NO_CXX11_STATIC_ASSERT
# define BOOST_STATIC_ASSERT( B ) static_assert(B, #B) # ifndef BOOST_NO_CXX11_VARIADIC_MACROS
# define BOOST_STATIC_ASSERT( ... ) static_assert(__VA_ARGS__, #__VA_ARGS__)
# else
# define BOOST_STATIC_ASSERT( B ) static_assert(B, #B)
# endif
#else #else
namespace boost{ namespace boost{
@ -119,17 +143,29 @@ template<int x> struct static_assert_test{};
sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >) ) sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >) )
#else #else
// generic version // generic version
#define BOOST_STATIC_ASSERT( B ) \ # ifndef BOOST_NO_CXX11_VARIADIC_MACROS
typedef ::boost::static_assert_test<\ # define BOOST_STATIC_ASSERT( ... ) \
sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >)>\ typedef ::boost::static_assert_test<\
BOOST_JOIN(boost_static_assert_typedef_, __LINE__) sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( __VA_ARGS__ ) >)>\
BOOST_JOIN(boost_static_assert_typedef_, __LINE__) BOOST_STATIC_ASSERT_UNUSED_ATTRIBUTE
# else
# define BOOST_STATIC_ASSERT( B ) \
typedef ::boost::static_assert_test<\
sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >)>\
BOOST_JOIN(boost_static_assert_typedef_, __LINE__) BOOST_STATIC_ASSERT_UNUSED_ATTRIBUTE
# endif
#endif #endif
#else #else
// alternative enum based implementation: // alternative enum based implementation:
#define BOOST_STATIC_ASSERT( B ) \ # ifndef BOOST_NO_CXX11_VARIADIC_MACROS
enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \ # define BOOST_STATIC_ASSERT( ... ) \
= sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >) } enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \
= sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( __VA_ARGS__ ) >) }
# else
enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \
= sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >) }
# endif
#endif #endif
#endif // defined(BOOST_NO_CXX11_STATIC_ASSERT) #endif // defined(BOOST_NO_CXX11_STATIC_ASSERT)

10
static_assert_test.cpp
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@ -58,6 +58,7 @@ struct Bob
template <class Int, class Char> template <class Int, class Char>
struct Bill struct Bill
{ {
BOOST_STATIC_CONSTANT(int, value = 1);
private: // can be in private, to avoid namespace pollution private: // can be in private, to avoid namespace pollution
BOOST_STATIC_ASSERT(sizeof(Int) > sizeof(char)); BOOST_STATIC_ASSERT(sizeof(Int) > sizeof(char));
BOOST_STATIC_ASSERT_MSG(sizeof(Int) > sizeof(char), "msg9"); BOOST_STATIC_ASSERT_MSG(sizeof(Int) > sizeof(char), "msg9");
@ -89,6 +90,15 @@ void test_Bill() // BOOST_STATIC_ASSERTs are not triggerred until instantiated
int main() int main()
{ {
test_Bill(); test_Bill();
//
// Test variadic macro support:
//
#ifndef BOOST_NO_CXX11_VARIADIC_MACROS
BOOST_STATIC_ASSERT(Bill<int, char>::value);
#ifndef BOOST_NO_CXX11_STATIC_ASSERT
BOOST_STATIC_ASSERT_MSG(Bill<int, char>::value, "This is a message");
#endif
#endif
return 0; return 0;
} }