sl@0: #ifndef BOOST_STATIC_WARNING_HPP
sl@0: #define BOOST_STATIC_WARNING_HPP
sl@0: 
sl@0: //  (C) Copyright Robert Ramey 2003. Jonathan Turkanis 2004.
sl@0: // Use, modification and distribution is subject to the Boost Software
sl@0: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
sl@0: // MS compatible compilers support #pragma once
sl@0: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
sl@0: # pragma once
sl@0: #endif
sl@0: 
sl@0: // http://www.boost.org/LICENSE_1_0.txt)
sl@0: 
sl@0: //  See http://www.boost.org/libs/static_assert for documentation.
sl@0: 
sl@0: /*
sl@0:  Revision history:
sl@0:    15 June  2003 - Initial version.
sl@0:    31 March 2004 - improved diagnostic messages and portability 
sl@0:                    (Jonathan Turkanis)
sl@0:    03 April 2004 - works on VC6 at class and namespace scope
sl@0:                  - ported to DigitalMars
sl@0:                  - static warnings disabled by default; when enabled,
sl@0:                    uses pragmas to enable required compiler warnings
sl@0:                    on MSVC, Intel, Metrowerks and Borland 5.x.
sl@0:                    (Jonathan Turkanis)
sl@0:    30 May 2004   - tweaked for msvc 7.1 and gcc 3.3
sl@0:                  - static warnings ENabled by default; when enabled,
sl@0:                    (Robert Ramey)
sl@0: */
sl@0: 
sl@0: #include <boost/config.hpp>
sl@0: 
sl@0: //
sl@0: // Implementation
sl@0: // Makes use of the following warnings:
sl@0: //  1. GCC prior to 3.3: division by zero.
sl@0: //  2. BCC 6.0 preview: unreferenced local variable.
sl@0: //  3. DigitalMars: returning address of local automatic variable.
sl@0: //  4. VC6: class previously seen as struct (as in 'boost/mpl/print.hpp')
sl@0: //  5. All others: deletion of pointer to incomplete type.
sl@0: //
sl@0: // The trick is to find code which produces warnings containing the name of
sl@0: // a structure or variable. Details, with same numbering as above:
sl@0: // 1. static_warning_impl<B>::value is zero iff B is false, so diving an int
sl@0: //    by this value generates a warning iff B is false.
sl@0: // 2. static_warning_impl<B>::type has a constructor iff B is true, so an
sl@0: //    unreferenced variable of this type generates a warning iff B is false.
sl@0: // 3. static_warning_impl<B>::type overloads operator& to return a dynamically
sl@0: //    allocated int pointer only is B is true, so  returning the address of an
sl@0: //    automatic variable of this type generates a warning iff B is fasle.
sl@0: // 4. static_warning_impl<B>::STATIC_WARNING is decalred as a struct iff B is 
sl@0: //    false. 
sl@0: // 5. static_warning_impl<B>::type is incomplete iff B is false, so deleting a
sl@0: //    pointer to this type generates a warning iff B is false.
sl@0: //
sl@0: 
sl@0: //------------------Enable selected warnings----------------------------------//
sl@0: 
sl@0: // Enable the warnings relied on by BOOST_STATIC_WARNING, where possible. The 
sl@0: // only pragma which is absolutely necessary here is for Borland 5.x, since 
sl@0: // W8073 is disabled by default. If enabling selected warnings is considered 
sl@0: // unacceptable, this section can be replaced with:
sl@0: //   #if defined(__BORLANDC__) && (__BORLANDC__ <= 0x600)
sl@0: //    pragma warn +stu
sl@0: //   #endif
sl@0: 
sl@0: # if defined(BOOST_MSVC)
sl@0: #  pragma warning(2:4150) // C4150: deletion of pointer to incomplete type 'type'.
sl@0: # elif defined(BOOST_INTEL) && (defined(__WIN32__) || defined(WIN32))
sl@0: #  pragma warning(2:457) // #457: delete of pointer to incomplete class.
sl@0: # elif defined(__BORLANDC__) && (__BORLANDC__ <= 0x600)
sl@0: #  pragma warn +stu  // W8073: Undefined structure 'structure'.
sl@0: # elif defined(__MWERKS__)
sl@0: #  pragma extended_errorcheck on // Enable 'extended error checking'.
sl@0: # endif
sl@0: 
sl@0: //------------------Configure-------------------------------------------------//
sl@0: 
sl@0: # if defined(__BORLANDC__) && (__BORLANDC__ >= 0x600)
sl@0: #  define BOOST_HAS_DESCRIPTIVE_UNREFERENCED_VARIABLE_WARNING
sl@0: # elif defined(__GNUC__) && !defined(BOOST_INTEL) // && (__GNUC__ * 100 + __GNUC_MINOR__ <= 302)
sl@0: #  define BOOST_HAS_DESCRIPTIVE_DIVIDE_BY_ZERO_WARNING
sl@0: # elif defined(__DMC__)
sl@0: #  define BOOST_HAS_DESCRIPTIVE_RETURNING_ADDRESS_OF_TEMPORARY_WARNING
sl@0: # elif defined(BOOST_MSVC) // && (BOOST_MSVC < 1300)
sl@0: #  define BOOST_NO_PREDEFINED_LINE_MACRO
sl@0: #  pragma warning(disable:4094) // C4094: untagged 'stuct' declared no symbols
sl@0: #endif
sl@0: 
sl@0: //------------------Helper templates------------------------------------------//
sl@0: 
sl@0: namespace boost {
sl@0: 
sl@0: struct STATIC_WARNING;
sl@0: 
sl@0: template<bool>
sl@0: struct static_warning_impl;
sl@0: 
sl@0: template<>
sl@0: struct static_warning_impl<false> {
sl@0:     enum { value = 0 };
sl@0:     #if !defined(BOOST_HAS_DESCRIPTIVE_UNREFERENCED_VARIABLE_WARNING) && \
sl@0:         !defined(BOOST_HAS_DESCRIPTIVE_RETURNING_ADDRESS_OF_TEMPORARY_WARNING)
sl@0:         typedef boost::STATIC_WARNING type;
sl@0:     #else
sl@0:         typedef int type;
sl@0:     #endif
sl@0:     #if defined(BOOST_NO_PREDEFINED_LINE_MACRO)
sl@0:         struct STATIC_WARNING { };
sl@0:     #endif
sl@0: };
sl@0: 
sl@0: template<>
sl@0: struct static_warning_impl<true> {
sl@0:     enum { value = 1 };
sl@0:     struct type { type() { } int* operator&() { return new int; } };
sl@0:     #if defined(BOOST_NO_PREDEFINED_LINE_MACRO)
sl@0:         class STATIC_WARNING { };
sl@0:     #endif
sl@0: };
sl@0: 
sl@0: } // namespace boost
sl@0: 
sl@0: //------------------Definition of BOOST_STATIC_WARNING------------------------//
sl@0: 
sl@0: #if defined(BOOST_HAS_DESCRIPTIVE_UNREFERENCED_VARIABLE_WARNING)
sl@0: #    define BOOST_STATIC_WARNING_IMPL(B)                   \
sl@0:      struct BOOST_JOIN(STATIC_WARNING, __LINE__) {         \
sl@0:        void f() {                                          \
sl@0:            ::boost::static_warning_impl<(bool)( B )>::type \
sl@0:            STATIC_WARNING;                                 \
sl@0:        }                                                   \
sl@0:      }                                                     \
sl@0:      /**/
sl@0: #elif defined(BOOST_HAS_DESCRIPTIVE_RETURNING_ADDRESS_OF_TEMPORARY_WARNING)
sl@0: #    define BOOST_STATIC_WARNING_IMPL(B)                        \
sl@0:      struct BOOST_JOIN(STATIC_WARNING, __LINE__) {              \
sl@0:         int* f() {                                              \
sl@0:             ::boost::static_warning_impl<(bool)( B )>::type     \
sl@0:             STATIC_WARNING;                                     \
sl@0:             return &STATIC_WARNING;                             \
sl@0:         }                                                       \
sl@0:      }                                                          \
sl@0:      /**/
sl@0: #elif defined(BOOST_HAS_DESCRIPTIVE_DIVIDE_BY_ZERO_WARNING)
sl@0: #    define BOOST_STATIC_WARNING_IMPL(B)                             \
sl@0:      struct BOOST_JOIN(STATIC_WARNING, __LINE__) {                   \
sl@0:          int f() { int STATIC_WARNING = 1;                           \
sl@0:                    return STATIC_WARNING /                           \
sl@0:                    boost::static_warning_impl<(bool)( B )>::value; } \
sl@0:      }                                                               \
sl@0:      /**/
sl@0: #elif defined(BOOST_NO_PREDEFINED_LINE_MACRO) 
sl@0:      // VC6; __LINE__ macro broken when -ZI is used see Q199057, so 
sl@0:      // non-conforming workaround is used.
sl@0: #    define BOOST_STATIC_WARNING_IMPL(B)                       \
sl@0:      struct {                                                  \
sl@0:         struct S {                                             \
sl@0:             typedef boost::static_warning_impl<(bool)( B )> f; \
sl@0:             friend class f::STATIC_WARNING;                    \
sl@0:         };                                                     \
sl@0:      }                                                         \
sl@0:      /**/
sl@0: #else // Deletion of pointer to incomplete type.
sl@0: #    define BOOST_STATIC_WARNING_IMPL(B)                     \
sl@0:      struct BOOST_JOIN(STATIC_WARNING, __LINE__) {           \
sl@0:          ::boost::static_warning_impl<(bool)( B )>::type* p; \
sl@0:          void f() { delete p; }                              \
sl@0:      }                                                       \
sl@0:      /**/
sl@0: #endif
sl@0: 
sl@0: #ifndef BOOST_DISABLE_STATIC_WARNINGS
sl@0: # define BOOST_STATIC_WARNING(B) BOOST_STATIC_WARNING_IMPL(B)
sl@0: #else // #ifdef BOOST_ENABLE_STATIC_WARNINGS //-------------------------------//
sl@0: # define BOOST_STATIC_WARNING(B) BOOST_STATIC_WARNING_IMPL(true)
sl@0: #endif
sl@0: 
sl@0: #endif // BOOST_STATIC_WARNING_HPP