std::numeric_limits::is_signed - cppreference.com (original) (raw)

| static const bool is_signed; | | (until C++11) | | --------------------------------- | | ------------- | | static constexpr bool is_signed; | | (since C++11) |

The value of std::numeric_limits<T>::is_signed is true for all signed arithmetic types T and false for the unsigned types. This constant is meaningful for all specializations.

[edit] Standard specializations

[edit] Example

#include #include #include   template struct test { test(const char* name, int w = 15) { std::cout << std::left << std::setw(w) << (std::numeric_limits::is_specialized ? name : "non-specialized") << " : " << (std::numeric_limits::is_signed ? "" : "un") << "signed\n"; } };   int main() { test{"bool"}; test{"char"}; test{"wchar_t"}; test{"char16_t"}; test{"char32_t"}; test{"float"}; struct delusion{}; test{"delusion"}; test<decltype(42)>{"decltype(42)"}; }

Possible output:

bool  : unsigned char  : signed wchar_t  : signed char16_t  : unsigned char32_t  : unsigned float  : signed non-specialized : unsigned decltype(42)  : signed

[edit] See also

| | checks if a type is a signed arithmetic type (class template) [edit] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | identifies integer types (public static member constant) [edit] | | | identifies exact types (public static member constant) [edit] | | | identifies types that represent a finite set of values (public static member constant) [edit] |