Created
December 3, 2018 09:56
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Get the type of a variable (C++17)
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| // This file is a "Hello, world!" in C++ language by GCC for wandbox. | |
| #include <iostream> | |
| #include <cstdlib> | |
| // https://stackoverflow.com/questions/81870/is-it-possible-to-print-a-variables-type-in-standard-c | |
| template <class T> | |
| constexpr | |
| std::string_view | |
| type_name() | |
| { | |
| using namespace std; | |
| #ifdef __clang__ | |
| string_view p = __PRETTY_FUNCTION__; | |
| return string_view(p.data() + 34, p.size() - 34 - 1); | |
| #elif defined(__GNUC__) | |
| string_view p = __PRETTY_FUNCTION__; | |
| # if __cplusplus < 201402 | |
| return string_view(p.data() + 36, p.size() - 36 - 1); | |
| # else | |
| return string_view(p.data() + 49, p.find(';', 49) - 49); | |
| # endif | |
| #elif defined(_MSC_VER) | |
| string_view p = __FUNCSIG__; | |
| return string_view(p.data() + 84, p.size() - 84 - 7); | |
| #endif | |
| } | |
| int main() | |
| { | |
| std::cout << "Hello, Wandbox!" << std::endl; | |
| int (*(*foo[5])(char(*)()))[3]; | |
| std::cout << "decltype(foo) is " << type_name<decltype(foo)>() << '\n'; | |
| } | |
| // GCC reference: | |
| // https://gcc.gnu.org/ | |
| // C++ language references: | |
| // https://msdn.microsoft.com/library/3bstk3k5.aspx | |
| // http://www.cplusplus.com/ | |
| // https://isocpp.org/ | |
| // http://www.open-std.org/jtc1/sc22/wg21/ | |
| // Boost libraries references: | |
| // http://www.boost.org/doc/ |
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