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< h1 > assert.hpp</ h1 >
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< p >
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< a href = "#BOOST_ASSERT" > BOOST_ASSERT</ a >< br />
< a href = "#BOOST_ASSERT_MSG" > BOOST_ASSERT_MSG</ a >< br />
< a href = "#BOOST_VERIFY" > BOOST_VERIFY</ a >< br />
< a href = "#BOOST_VERIFY_MSG" > BOOST_VERIFY_MSG</ a >< br />
</ p >
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< h2 >< a name = "BOOST_ASSERT" > BOOST_ASSERT</ a ></ h2 >
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< p >
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The header < code > < boost/assert.hpp> </ code > defines the macro < code > BOOST_ASSERT</ code > ,
which is similar to the standard < code > assert</ code > macro defined in < code > < cassert> </ code > .
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The macro is intended to be used in both Boost libraries and user
code.
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</ p >
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< p > • By default, < code > BOOST_ASSERT(expr)</ code > expands to < code > assert(expr)</ code > .</ p >
< p > • If the macro < code > BOOST_DISABLE_ASSERTS</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_ASSERT(expr)</ code > expands to < code > ((void)0)</ code > , regardless of whether
the macro < code > NDEBUG</ code > is defined. This allows users to selectively disable < code > BOOST_ASSERT</ code > without
affecting the definition of the standard < code > assert</ code > .</ p >
< p > • If the macro < code > BOOST_ENABLE_ASSERT_HANDLER</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_ASSERT(expr)</ code > expands to</ p >
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< blockquote >
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< pre > (< a href = "../config/doc/html/boost_config/boost_macro_reference.html#boost_config.boost_macro_reference.boost_helper_macros" > BOOST_LIKELY</ a > (!!(expr))? ((void)0): ::boost::assertion_failed(#expr, < a href = "current_function.html" > BOOST_CURRENT_FUNCTION</ a > , __FILE__, __LINE__))</ pre >
</ blockquote >
< p > That is, it evaluates < code > expr</ code > and if it's false, calls < code > ::boost::assertion_failed(#expr, BOOST_CURRENT_FUNCTION, __FILE__, __LINE__)</ code > .
This is true regardless of whether < code > NDEBUG</ code > is defined.</ p >
< p >< code > boost::assertion_failed</ code > is declared in < code > < boost/assert.hpp> </ code > as</ p >
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< blockquote >
< pre > namespace boost
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{
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void assertion_failed(char const * expr, char const * function, char const * file, long line);
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}
</ pre >
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</ blockquote >
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< p > but it is never defined. The user is expected to supply an appropriate
definition.</ p >
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< p > • If the macro < code > BOOST_ENABLE_ASSERT_DEBUG_HANDLER</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_ASSERT(expr)</ code > expands to < code > ((void)0)</ code > when < code > NDEBUG</ code > is
defined. Otherwise the behavior is as if < code > BOOST_ENABLE_ASSERT_HANDLER</ code > has been defined.</ p >
< p > As is the case with < code > < cassert> </ code > , < code > < boost/assert.hpp> </ code >
can be included multiple times in a single translation unit. < code > BOOST_ASSERT</ code >
will be redefined each time as specified above.</ p >
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< h2 >< a name = "BOOST_ASSERT_MSG" > BOOST_ASSERT_MSG</ a ></ h2 >
< p >
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The macro < code > BOOST_ASSERT_MSG</ code > is similar to < code > BOOST_ASSERT</ code > , but it takes an additional argument,
a character literal, supplying an error message.</ p >
< p > • By default, < code > BOOST_ASSERT_MSG(expr,msg)</ code > expands to < code > assert((expr)&& (msg))</ code > .</ p >
< p > • If the macro < code > BOOST_DISABLE_ASSERTS</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_ASSERT_MSG(expr,msg)</ code > expands to < code > ((void)0)</ code > , regardless of whether
the macro < code > NDEBUG</ code > is defined.</ p >
< p > • If the macro < code > BOOST_ENABLE_ASSERT_HANDLER</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_ASSERT_MSG(expr,msg)</ code > expands to</ p >
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< blockquote >
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< pre > (< a href = "../config/doc/html/boost_config/boost_macro_reference.html#boost_config.boost_macro_reference.boost_helper_macros" > BOOST_LIKELY</ a > (!!(expr))? ((void)0): ::boost::assertion_failed_msg(#expr, msg, < a href = "current_function.html" > BOOST_CURRENT_FUNCTION</ a > , __FILE__, __LINE__))</ pre >
</ blockquote >
< p > This is true regardless of whether < code > NDEBUG</ code > is defined.</ p >
< p >< code > boost::assertion_failed_msg</ code > is declared in < code > < boost/assert.hpp> </ code > as</ p >
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< blockquote >
< pre > namespace boost
{
void assertion_failed_msg(char const * expr, char const * msg, char const * function, char const * file, long line);
}
</ pre >
</ blockquote >
< p > but it is never defined. The user is expected to supply an appropriate
definition.</ p >
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< p > • If the macro < code > BOOST_ENABLE_ASSERT_DEBUG_HANDLER</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_ASSERT_MSG(expr)</ code > expands to < code > ((void)0)</ code > when < code > NDEBUG</ code > is
defined. Otherwise the behavior is as if < code > BOOST_ENABLE_ASSERT_HANDLER</ code > has been defined.</ p >
< p > As is the case with < code > < cassert> </ code > , < code > < boost/assert.hpp> </ code >
can be included multiple times in a single translation unit. < code > BOOST_ASSERT_MSG</ code >
will be redefined each time as specified above.</ p >
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< h2 >< a name = "BOOST_VERIFY" > BOOST_VERIFY</ a ></ h2 >
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< p > The macro < code > BOOST_VERIFY</ code > has the same behavior as < code > BOOST_ASSERT</ code > , except that
the expression that is passed to < code > BOOST_VERIFY</ code > is always
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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.</ p >
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< p > • If the macro < code > BOOST_DISABLE_ASSERTS</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_VERIFY(expr)</ code > expands to < code > ((void)(expr))</ code > .</ p >
< p > • If the macro < code > BOOST_ENABLE_ASSERT_HANDLER</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_VERIFY(expr)</ code > expands to < code > BOOST_ASSERT(expr)</ code > .</ p >
< p > • Otherwise, < code > BOOST_VERIFY(expr)</ code > expands to < code > ((void)(expr))</ code > when < code > NDEBUG</ code > is
defined, to < code > BOOST_ASSERT(expr)</ code > when it's not.</ p >
< h2 >< a name = "BOOST_VERIFY_MSG" > BOOST_VERIFY_MSG</ a ></ h2 >
< p > The macro < code > BOOST_VERIFY_MSG</ code > is similar to < code > BOOST_VERIFY</ code > , with an additional parameter, an error message.</ p >
< p > • If the macro < code > BOOST_DISABLE_ASSERTS</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_VERIFY_MSG(expr,msg)</ code > expands to < code > ((void)(expr))</ code > .</ p >
< p > • If the macro < code > BOOST_ENABLE_ASSERT_HANDLER</ code > is defined when < code > < boost/assert.hpp> </ code >
is included, < code > BOOST_VERIFY_MSG(expr,msg)</ code > expands to < code > BOOST_ASSERT_MSG(expr,msg)</ code > .</ p >
< p > • Otherwise, < code > BOOST_VERIFY_MSG(expr,msg)</ code > expands to < code > ((void)(expr))</ code > when < code > NDEBUG</ code > is
defined, to < code > BOOST_ASSERT_MSG(expr,msg)</ code > when it's not.</ p >
< hr />
< p >
< small > Copyright © 2002, 2007, 2014 by Peter Dimov. Copyright © 2011
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by Beman Dawes. Distributed under the Boost Software
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License, Version 1.0. See accompanying file < a href = "../../LICENSE_1_0.txt" > LICENSE_1_0.txt</ a >
or copy at < a href = "http://www.boost.org/LICENSE_1_0.txt" > http://www.boost.org/LICENSE_1_0.txt</ a > .</ small ></ p >
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