std::numeric_limits<T>::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 |
char8_t (C++20) |
usually true |
char16_t (C++11) |
usually true |
char32_t (C++11) |
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 (C++11) |
usually true |
unsigned long long (C++11) |
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) |
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