core/doc/demangle.qbk

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[/
Copyright 2014 Peter Dimov
Copyright 2014 Andrey Semashev
Distributed under the Boost Software License, Version 1.0.
See accompanying file LICENSE_1_0.txt
or copy at http://boost.org/LICENSE_1_0.txt
]
[section:demangle demangle]
[simplesect Authors]
* Peter Dimov
* Andrey Semashev
[endsimplesect]
[section Header <boost/core/demangle.hpp>]
The header `<boost/core/demangle.hpp>` defines several tools for undecorating
symbol names.
[section Synopsis]
namespace boost
{
namespace core
{
std::string demangle( char const * name );
char const * demangle_alloc( char const * name ) noexcept;
void demangle_free( char const * demangled_name ) noexcept;
class scoped_demangled_name
{
public:
explicit scoped_demangled_name( char const * name ) noexcept;
~scoped_demangled_name() noexcept;
char const * get() const noexcept;
scoped_demangled_name( scoped_demangled_name const& ) = delete;
scoped_demangled_name& operator= ( scoped_demangled_name const& ) = delete;
};
}
}
[endsect]
[section Conventional interface]
The function `boost::core::demangle` is the conventional
way to obtain demangled symbol name. It takes a mangled string such as
those returned by `typeid(T).name()` on certain implementations
such as `g++`, and returns its demangled, human-readable, form. In case if
demangling fails (e.g. if `name` cannot be interpreted as a mangled name)
the function returns `name`.
[section Example]
#include <boost/core/demangle.hpp>
#include <typeinfo>
#include <iostream>
template<class T> struct X
{
};
int main()
{
char const * name = typeid( X<int> ).name();
std::cout << name << std::endl; // prints 1XIiE
std::cout << boost::core::demangle( name ) << std::endl; // prints X<int>
}
[endsect]
[endsect]
[section Low level interface]
In some cases more low level interface may be desirable. For example:
* Assuming that symbol demangling may fail, the user wants to be able to handle such errors.
* The user needs to post-process the demangled name (e.g. remove common namespaces), and
allocating a temporary string with the complete demangled name is significant overhead.
The function `boost::core::demangle_alloc` performs name demangling and returns a pointer
to a string with the demangled name, if succeeded, or `nullptr` otherwise. The returned pointer
must be passed to `boost::core::demangle_free` to reclaim resources. Note that on some platforms
the pointer returned by `boost::core::demangle_alloc` may refer to the string denoted by `name`,
so this string must be kept immutable for the whole life time of the returned pointer.
The `boost::core::scoped_demangled_name` class is a scope guard that automates the calls to
`boost::core::demangle_alloc` (on its construction) and `boost::core::demangle_free` (on destruction).
The string with the demangled name can be obtained with its `get` method. Note that this method may
return `nullptr` if demangling failed.
[section Example]
#include <boost/core/demangle.hpp>
#include <typeinfo>
#include <iostream>
template<class T> struct X
{
};
int main()
{
char const * name = typeid( X<int> ).name();
boost::core::scoped_demangled_name demangled( name );
std::cout << name << std::endl; // prints 1XIiE
std::cout << (demangled.get() ? demangled.get() : "[unknown]") << std::endl; // prints X<int>
}
[endsect]
[endsect]
[endsect]
[section Acknowledgments]
The implementation of `core::demangle` was taken from
`boost/exception/detail/type_info.hpp`, which in turn was adapted
from `boost/units/detail/utility.hpp` and `boost/log/utility/type_info_wrapper.hpp`.
[endsect]
[endsect]