std::numeric_limits::traps
| static const bool traps |
(until C++11) | |
| static constexpr bool traps |
(since C++11) | |
The value of std::numeric_limits<T>::traps is true for all arithmetic types T that have at least one value that, if used as an argument to an arithmetic operation, will generate a trap.
Standard specializations
T
|
value of std::numeric_limits<T>::traps |
| /* non-specialized */ | false |
| bool | false |
| char | usually true |
| signed char | usually true |
| unsigned char | usually true |
| wchar_t | usually true |
| char16_t | usually true |
| char32_t | usually true |
| short | usually true |
| unsigned short | usually true |
| int | usually true |
| unsigned int | usually true |
| long | usually true |
| unsigned long | usually true |
| long long | usually true |
| unsigned long long | usually true |
| float | usually false |
| double | usually false |
| long double | usually false |
Notes
On most platforms integer division by zero always traps, and std::numeric_limits<T>::traps is true for all integer types that support the value 0. The exception is the type bool: even though division by false traps due to integral promotion from bool to int, it is the zero-valued int that traps. Zero is not a value of type bool.
On most platforms, floating-point exceptions may be turned on and off at run time (e.g. feenableexcept() on Linux or _controlfp on Windows), in which case the value of std::numeric_limits<T>::traps for floating-point types reflects the state of floating-point trapping facility at the time of program startup, which is false on most modern systems. An exception would be a DEC Alpha program, where it is true if compiled without -ieee.
See also
| Floating-point environment | |
| [static] |
identifies floating-point types that detect tinyness before rounding (public static member constant) |
| [static] |
identifies the floating-point types that detect loss of precision as denormalization loss rather than inexact result (public static member constant) |