Chris@16: //  This header intentionally has no include guards.
Chris@16: //
Chris@16: //  Copyright (c) 2001-2009, 2012 Peter Dimov
Chris@16: //
Chris@16: //  Distributed under the Boost Software License, Version 1.0.
Chris@16: //  See accompanying file LICENSE_1_0.txt or copy at
Chris@16: //  http://www.boost.org/LICENSE_1_0.txt
Chris@16: 
Chris@16: #if !defined( BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS ) && !defined( BOOST_NO_CXX11_NULLPTR )
Chris@16: 
Chris@16:     explicit operator bool () const BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         return px != 0;
Chris@16:     }
Chris@16: 
Chris@16: #elif ( defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, < 0x570) ) || defined(__CINT__)
Chris@16: 
Chris@16:     operator bool () const BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         return px != 0;
Chris@16:     }
Chris@16: 
Chris@16: #elif defined( _MANAGED )
Chris@16: 
Chris@16:     static void unspecified_bool( this_type*** )
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     typedef void (*unspecified_bool_type)( this_type*** );
Chris@16: 
Chris@16:     operator unspecified_bool_type() const BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         return px == 0? 0: unspecified_bool;
Chris@16:     }
Chris@16: 
Chris@16: #elif \
Chris@16:     ( defined(__MWERKS__) && BOOST_WORKAROUND(__MWERKS__, < 0x3200) ) || \
Chris@16:     ( defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ < 304) ) || \
Chris@16:     ( defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, <= 0x590) )
Chris@16: 
Chris@16:     typedef element_type * (this_type::*unspecified_bool_type)() const;
Chris@16: 
Chris@16:     operator unspecified_bool_type() const BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         return px == 0? 0: &this_type::get;
Chris@16:     }
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16:     typedef element_type * this_type::*unspecified_bool_type;
Chris@16: 
Chris@16:     operator unspecified_bool_type() const BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         return px == 0? 0: &this_type::px;
Chris@16:     }
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16:     // operator! is redundant, but some compilers need it
Chris@16:     bool operator! () const BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         return px == 0;
Chris@16:     }