std::type_info::name

 

C++

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Utilities library

Language support Type support (basic types, RTTI) Library feature-test macros (C++20) Dynamic memory management Program utilities Coroutine support (C++20) Variadic functions is_constant_evaluated (C++20) is_within_lifetime (C++26) initializer_list (C++11) source_location (C++20) Three-way comparison (C++20) three_way_comparablethree_way_comparable_with (C++20)(C++20) strong_ordering (C++20) weak_ordering (C++20) partial_ordering (C++20) common_comparison_category (C++20) compare_three_way_result (C++20) compare_three_way (C++20) strong_order (C++20) weak_order (C++20) partial_order (C++20) compare_strong_order_fallback (C++20) compare_weak_order_fallback (C++20) compare_partial_order_fallback (C++20)    is_eqis_neqis_ltis_lteqis_gtis_gteq (C++20)(C++20)(C++20)(C++20)(C++20)(C++20)

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Type support

Basic types
Fixed width integer types (C++11)
Fixed width floating-point types (C++23)
ptrdiff_t size_t max_align_t (C++11)     byte (C++17)	nullptr_t (C++11) offsetof NULL
Numeric limits
numeric_limits
C numeric limits interface
Runtime type information
type_info type_index (C++11)	bad_typeid bad_cast

 

std::type_info

Member functions

type_info::~type_info

type_info::operator==type_info::operator!= (until C++20)

type_info::before

type_info::hash_code (C++11)

type_info::name

 

const char* name() const;		(until C++11)
const char* name() const noexcept;		(since C++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 C++ 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 <iostream>
#include <cstdlib>
#include <string>
#include <typeinfo>
 
#include <boost/core/demangle.hpp>
 
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 << "c++filt => " << std::flush;
    std::string s = typeid(pb).name();
    std::system(("c++filt -t " + s).data());
}

Possible output:

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

See also

hash_code (C++11)

returns a value which is identical for the same types (public member function)