1.. Macros/Asserts//BOOST_MPL_ASSERT_NOT 2 3BOOST_MPL_ASSERT_NOT 4==================== 5 6Synopsis 7-------- 8 9.. parsed-literal:: 10 11 #define BOOST_MPL_ASSERT_NOT( pred ) \\ 12 |unspecified-token-seq| \\ 13 /\*\*/ 14 15 16Description 17----------- 18 19Generates a compilation error when predicate holds true. 20 21 22Header 23------ 24 25.. parsed-literal:: 26 27 #include <boost/mpl/assert.hpp> 28 29 30Parameters 31---------- 32 33+---------------+-----------------------------------+-------------------------------------------+ 34| Parameter | Requirement | Description | 35+===============+===================================+===========================================+ 36| ``pred`` | Boolean nullary |Metafunction| | A predicate to be asserted to be false. | 37+---------------+-----------------------------------+-------------------------------------------+ 38 39 40Expression semantics 41-------------------- 42 43For any boolean nullary |Metafunction| ``pred``: 44 45 46.. parsed-literal:: 47 48 BOOST_MPL_ASSERT_NOT(( pred )); 49 50:Return type: 51 None. 52 53:Semantics: 54 Generates a compilation error if ``pred::type::value != false``, otherwise 55 has no effect. Note that double parentheses are required even if no commas 56 appear in the condition. 57 58 When possible within the compiler's diagnostic capabilities, 59 the error message will include the predicate's full type name, and have a 60 general form of: 61 62 .. parsed-literal:: 63 64 |...| \*\*\*\*\*\*\*\*\*\*\*\*boost::mpl::not_< pred >::\*\*\*\*\*\*\*\*\*\*\*\* |...| 65 66 67Example 68------- 69 70:: 71 72 template< typename T, typename U > struct my 73 { 74 // ... 75 BOOST_MPL_ASSERT_NOT(( is_same< T,U > )); 76 }; 77 78 my<void,void> test; 79 80 // In instantiation of `my<void, void>': 81 // instantiated from here 82 // conversion from ` 83 // mpl_::failed************boost::mpl::not_<boost::is_same<void, void> 84 // >::************' to non-scalar type `mpl_::assert<false>' requested 85 86 87See also 88-------- 89 90|Asserts|, |BOOST_MPL_ASSERT|, |BOOST_MPL_ASSERT_MSG|, |BOOST_MPL_ASSERT_RELATION| 91 92 93.. copyright:: Copyright � 2001-2009 Aleksey Gurtovoy and David Abrahams 94 Distributed under the Boost Software License, Version 1.0. (See accompanying 95 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 96