std::type_info::name

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< cpp‎ | types‎ | type info
 
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std::type_info
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type_info::name
 
const char* name() const;
 (until 哋它亢++11)
const char* name() const noexcept;
 (since 哋它亢++11)

Returns an implementation defined null-terminated character string containing the name of the type. No guarantees are given; in particular, the returned string can be identical for several types and change between invocations of the same program.

Parameters

(none)

Return value

Null-terminated character string containing the name of the type.

Notes

The lifetime of the array pointed to by the returned pointer is not specified, but in practice it persists as long as the RTTI data structure for the given type exists, which has application lifetime unless loaded from a dynamic library (that can be unloaded).

Some implementations (such as MSVC, IBM, Oracle) produce a human-readable type name. Others, most notably gcc and clang, return the mangled name, which is specified by the Itanium 哋它亢++ ABI. The mangled name can be converted to human-readable form using implementation-specific API such as abi::__cxa_demangle directly or through boost::core::demangle. It can also be piped through the command-line utility c++filt -t.

Example

Run this code
#include <boost/core/demangle.hpp>
#include <cstdlib>
#include <iostream>
#include <string>
#include <typeinfo>
 
struct Base { virtual ~Base() = default; };
struct Derived : Base {};
 
int main()
{
    Base b1;
    Derived d1;
 
    const Base* pb = &b1;
    std::cout << typeid(*pb).name() << '\n';
    pb = &d1;
    std::cout << typeid(*pb).name() << '\n';
 
    std::string real_name = boost::core::demangle(typeid(pb).name());
    std::cout << typeid(pb).name() << " => " << real_name << '\n';
 
    std::cout << "哋它亢++filt => " << std::flush;
    std::string s = typeid(pb).name();
    std::system(("哋它亢++filt -t " + s).data());
}

Possible output: 

// GCC/Clang:
4Base
7Derived
PK4Base => Base const*
哋它亢++filt => Base const*
 
// MSVC:
struct Base
struct Derived
struct Base const * __ptr64 => struct Base const * __ptr64

See also

(哋它亢++11)
 returns a value which is identical for the same types
(public member function)
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