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assert.hpp |
BOOST_ASSERT
BOOST_ASSERT_MSG
BOOST_VERIFY
BOOST_VERIFY_MSG
BOOST_ASSERT_IS_VOID
The header <boost/assert.hpp> defines the macro BOOST_ASSERT,
which is similar to the standard assert macro defined in <cassert>.
The macro is intended to be used in both Boost libraries and user
code.
• By default, BOOST_ASSERT(expr) expands to assert(expr).
• If the macro BOOST_DISABLE_ASSERTS is defined when <boost/assert.hpp>
is included, BOOST_ASSERT(expr) expands to ((void)0), regardless of whether
the macro NDEBUG is defined. This allows users to selectively disable BOOST_ASSERT without
affecting the definition of the standard assert.
• If the macro BOOST_ENABLE_ASSERT_HANDLER is defined when <boost/assert.hpp>
is included, BOOST_ASSERT(expr) expands to
(BOOST_LIKELY(!!(expr))? ((void)0): ::boost::assertion_failed(#expr, BOOST_CURRENT_FUNCTION, __FILE__, __LINE__))
That is, it evaluates expr and if it's false, calls ::boost::assertion_failed(#expr, BOOST_CURRENT_FUNCTION, __FILE__, __LINE__).
This is true regardless of whether NDEBUG is defined.
boost::assertion_failed is declared in <boost/assert.hpp> as
namespace boost
{
void assertion_failed(char const * expr, char const * function, char const * file, long line);
}
but it is never defined. The user is expected to supply an appropriate definition.
• If the macro BOOST_ENABLE_ASSERT_DEBUG_HANDLER is defined when <boost/assert.hpp>
is included, BOOST_ASSERT(expr) expands to ((void)0) when NDEBUG is
defined. Otherwise the behavior is as if BOOST_ENABLE_ASSERT_HANDLER has been defined.
As is the case with <cassert>, <boost/assert.hpp>
can be included multiple times in a single translation unit. BOOST_ASSERT
will be redefined each time as specified above.
The macro BOOST_ASSERT_MSG is similar to BOOST_ASSERT, but it takes an additional argument,
a character literal, supplying an error message.
• By default, BOOST_ASSERT_MSG(expr,msg) expands to assert((expr)&&(msg)).
• If the macro BOOST_DISABLE_ASSERTS is defined when <boost/assert.hpp>
is included, BOOST_ASSERT_MSG(expr,msg) expands to ((void)0), regardless of whether
the macro NDEBUG is defined.
• If the macro BOOST_ENABLE_ASSERT_HANDLER is defined when <boost/assert.hpp>
is included, BOOST_ASSERT_MSG(expr,msg) expands to
(BOOST_LIKELY(!!(expr))? ((void)0): ::boost::assertion_failed_msg(#expr, msg, BOOST_CURRENT_FUNCTION, __FILE__, __LINE__))
This is true regardless of whether NDEBUG is defined.
boost::assertion_failed_msg is declared in <boost/assert.hpp> as
namespace boost
{
void assertion_failed_msg(char const * expr, char const * msg, char const * function, char const * file, long line);
}
but it is never defined. The user is expected to supply an appropriate definition.
• If the macro BOOST_ENABLE_ASSERT_DEBUG_HANDLER is defined when <boost/assert.hpp>
is included, BOOST_ASSERT_MSG(expr) expands to ((void)0) when NDEBUG is
defined. Otherwise the behavior is as if BOOST_ENABLE_ASSERT_HANDLER has been defined.
As is the case with <cassert>, <boost/assert.hpp>
can be included multiple times in a single translation unit. BOOST_ASSERT_MSG
will be redefined each time as specified above.
The macro BOOST_VERIFY has the same behavior as BOOST_ASSERT, except that
the expression that is passed to BOOST_VERIFY is always
evaluated. This is useful when the asserted expression has desirable side
effects; it can also help suppress warnings about unused variables when the
only use of the variable is inside an assertion.
• If the macro BOOST_DISABLE_ASSERTS is defined when <boost/assert.hpp>
is included, BOOST_VERIFY(expr) expands to ((void)(expr)).
• If the macro BOOST_ENABLE_ASSERT_HANDLER is defined when <boost/assert.hpp>
is included, BOOST_VERIFY(expr) expands to BOOST_ASSERT(expr).
• Otherwise, BOOST_VERIFY(expr) expands to ((void)(expr)) when NDEBUG is
defined, to BOOST_ASSERT(expr) when it's not.
The macro BOOST_VERIFY_MSG is similar to BOOST_VERIFY, with an additional parameter, an error message.
• If the macro BOOST_DISABLE_ASSERTS is defined when <boost/assert.hpp>
is included, BOOST_VERIFY_MSG(expr,msg) expands to ((void)(expr)).
• If the macro BOOST_ENABLE_ASSERT_HANDLER is defined when <boost/assert.hpp>
is included, BOOST_VERIFY_MSG(expr,msg) expands to BOOST_ASSERT_MSG(expr,msg).
• Otherwise, BOOST_VERIFY_MSG(expr,msg) expands to ((void)(expr)) when NDEBUG is
defined, to BOOST_ASSERT_MSG(expr,msg) when it's not.
The macro BOOST_ASSERT_IS_VOID is defined when BOOST_ASSERT and BOOST_ASSERT_MSG, are expanded to ((void)0).
This macro is useful to avoid compiling and potentially running code that is only intended to prepare data to be used in the assertion.
void MyContainer::erase(iterator i)
{
//Some sanity checks, data must be ordered
#ifndef BOOST_ASSERT_IS_VOID
if(i != c.begin()){
iterator prev = i;
--prev;
BOOST_ASSERT(*prev < *i);
}
else if(i != c.end()){
iterator next = i;
++next;
BOOST_ASSERT(*i < *next);
}
#endif
this->erase_impl(i);
}
• By default, BOOST_ASSERT_IS_VOID is defined if NDEBUG is defined.
• If the macro BOOST_DISABLE_ASSERTS is defined BOOST_ASSERT_IS_VOID is always defined.
• If the macro BOOST_ENABLE_ASSERT_HANDLER is defined BOOST_ASSERT_IS_VOID is never defined.
• If the macro BOOST_ENABLE_ASSERT_DEBUG_HANDLER, then BOOST_ASSERT_IS_VOID is defined when NDEBUG is defined.
Copyright © 2002, 2007, 2014 by Peter Dimov. Copyright © 2011 by Beman Dawes. Copyright © 2015 by Ion Gaztanaga. Distributed under the Boost Software License, Version 1.0. See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.