The Boost.Assert library provides several configurable diagnostic macros
similar in behavior and purpose to the standard macro assert from <cassert>.
Assertion Macros, <boost/assert.hpp>
BOOST_ASSERT
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.
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By default, BOOST_ASSERT(expr)expands toassert(expr).
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If the macro BOOST_DISABLE_ASSERTSis defined when<boost/assert.hpp>is included,BOOST_ASSERT(expr)expands to((void)0), regardless of whether the macroNDEBUGis defined. This allows users to selectively disableBOOST_ASSERTwithout affecting the definition of the standardassert.
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If the macro BOOST_ENABLE_ASSERT_HANDLERis 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 exprand if it’s false, calls::boost::assertion_failed(#expr, BOOST_CURRENT_FUNCTION, __FILE__, __LINE__). This is true regardless of whetherNDEBUGis defined.boost::assertion_failedis declared in<boost/assert.hpp>asnamespace 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. 
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If the macro BOOST_ENABLE_ASSERT_DEBUG_HANDLERis defined when<boost/assert.hpp>is included,BOOST_ASSERT(expr)expands to((void)0)whenNDEBUGis defined. Otherwise the behavior is as ifBOOST_ENABLE_ASSERT_HANDLERhas 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.
BOOST_ASSERT_MSG
The macro BOOST_ASSERT_MSG is similar to BOOST_ASSERT, but it takes an additional argument,
a character literal, supplying an error message.
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By default, BOOST_ASSERT_MSG(expr,msg)expands toassert((expr)&&(msg)).
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If the macro BOOST_DISABLE_ASSERTSis defined when<boost/assert.hpp>is included,BOOST_ASSERT_MSG(expr,msg)expands to((void)0), regardless of whether the macroNDEBUGis defined.
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If the macro BOOST_ENABLE_ASSERT_HANDLERis 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 NDEBUGis defined.boost::assertion_failed_msgis declared in<boost/assert.hpp>asnamespace 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. 
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If the macro BOOST_ENABLE_ASSERT_DEBUG_HANDLERis defined when<boost/assert.hpp>is included,BOOST_ASSERT_MSG(expr)expands to((void)0)whenNDEBUGis defined. Otherwise the behavior is as ifBOOST_ENABLE_ASSERT_HANDLERhas 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.
BOOST_VERIFY
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.
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If the macro BOOST_DISABLE_ASSERTSis defined when<boost/assert.hpp>is included,BOOST_VERIFY(expr)expands to((void)(expr)).
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If the macro BOOST_ENABLE_ASSERT_HANDLERis defined when<boost/assert.hpp>is included,BOOST_VERIFY(expr)expands toBOOST_ASSERT(expr).
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Otherwise, BOOST_VERIFY(expr)expands to((void)(expr))whenNDEBUGis defined, toBOOST_ASSERT(expr)when it’s not.
BOOST_VERIFY_MSG
The macro BOOST_VERIFY_MSG is similar to BOOST_VERIFY, with an additional parameter, an error message.
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If the macro BOOST_DISABLE_ASSERTSis defined when<boost/assert.hpp>is included,BOOST_VERIFY_MSG(expr,msg)expands to((void)(expr)).
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If the macro BOOST_ENABLE_ASSERT_HANDLERis defined when<boost/assert.hpp>is included,BOOST_VERIFY_MSG(expr,msg)expands toBOOST_ASSERT_MSG(expr,msg).
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Otherwise, BOOST_VERIFY_MSG(expr,msg)expands to((void)(expr))whenNDEBUGis defined, toBOOST_ASSERT_MSG(expr,msg)when it’s not.
BOOST_ASSERT_IS_VOID
The macro BOOST_ASSERT_IS_VOID is defined when BOOST_ASSERT and BOOST_ASSERT_MSG are expanded to ((void)0).
Its purpose is 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_VOIDis defined ifNDEBUGis defined.
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If the macro BOOST_DISABLE_ASSERTSis defined,BOOST_ASSERT_IS_VOIDis always defined.
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If the macro BOOST_ENABLE_ASSERT_HANDLERis defined,BOOST_ASSERT_IS_VOIDis never defined.
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If the macro BOOST_ENABLE_ASSERT_DEBUG_HANDLERis defined, thenBOOST_ASSERT_IS_VOIDis defined whenNDEBUGis defined.
Current Function Macro, <boost/current_function.hpp>
BOOST_CURRENT_FUNCTION
The header <boost/current_function.hpp> defines a single macro, BOOST_CURRENT_FUNCTION,
similar to the C99 predefined identifier __func__.
BOOST_CURRENT_FUNCTION expands to a string literal containing
the (fully qualified, if possible) name of the enclosing function. If there is
no enclosing function, the behavior is unspecified.
Some compilers do not provide a way to obtain the name of the current enclosing
function. On such compilers, or when the macro BOOST_DISABLE_CURRENT_FUNCTION
is defined, BOOST_CURRENT_FUNCTION expands to "(unknown)".
BOOST_DISABLE_CURRENT_FUNCTION addresses a use case in which the programmer
wishes to eliminate the string literals produced by BOOST_CURRENT_FUNCTION from
the final executable for security reasons.
Source Location Support, <boost/assert/source_location.hpp>
Description
The header <boost/assert/source_location.hpp> defines source_location,
a class representing a source location and containing file, line, function
and column information. It’s similar to std::source_location from C++20,
but only requires C++03.
The macro BOOST_CURRENT_LOCATION creates a source_location object
containing information about the current source location.
Synopsis
namespace boost
{
struct source_location
{
    constexpr source_location() noexcept;
    constexpr source_location(char const* file, uint_least32_t line,
      char const* function, uint_least32_t column = 0) noexcept;
    constexpr char const* file_name() const noexcept;
    constexpr char const* function_name() const noexcept;
    constexpr uint_least32_t line() const noexcept;
    constexpr uint_least32_t column() const noexcept;
    std::string to_string() const;
};
template<class E, class T>
  std::basic_ostream<E, T> &
    operator<<( std::basic_ostream<E, T> & os, source_location const & loc );
} // namespace boost
#define BOOST_CURRENT_LOCATION \
  ::boost::source_location(__FILE__, __LINE__, BOOST_CURRENT_FUNCTION)source_location
constexpr source_location() noexcept;- Effects:
- 
Constructs a source_locationobject for whichfile_name()andfunction_name()return"(unknown)", andline()andcolumn()return0.
constexpr source_location(char const* file, uint_least32_t line,
  char const* function, uint_least32_t column = 0) noexcept;- Effects:
- 
Constructs a source_locationobject for whichfile_name()returnsfile,function_name()returnsfunction,line()returns thelineargument andcolumn()returns thecolumnargument.
to_string
std::string to_string() const;- Returns:
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a string representation of *this.
operator<<
template<class E, class T>
  std::basic_ostream<E, T> &
    operator<<( std::basic_ostream<E, T> & os, source_location const & loc );- Effects:
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os << loc.to_string().
- Returns:
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os.
BOOST_CURRENT_LOCATION
When BOOST_DISABLE_CURRENT_LOCATION is not defined, the definition of
BOOST_CURRENT_LOCATION is:
#define BOOST_CURRENT_LOCATION \
  ::boost::source_location(__FILE__, __LINE__, BOOST_CURRENT_FUNCTION)Otherwise, BOOST_CURRENT_LOCATION is defined as:
#define BOOST_CURRENT_LOCATION ::boost::source_location()This allows producing executables that contain no identifying information, for security reasons.
Revision History
Changes in 1.78.0
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Added source_location::to_string.
Changes in 1.73.0
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Added source_location.
Appendix A: Copyright and License
This documentation is
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Copyright 2002, 2007, 2014, 2017, 2019-2021 Peter Dimov 
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Copyright 2011 Beman Dawes 
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Copyright 2015 Ion GaztaƱaga 
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Distributed under the Boost Software License, Version 1.0.