The value ofstd::numeric_limits<T>::traps istrue for all arithmetic typesT that have at least one value at the start of the program that, if used as an argument to an arithmetic operation, will generate atrap.

[edit]Standard specializations

[edit]Notes

On most platforms integer division by zero always traps, andstd::numeric_limits<T>::traps istrue for all integer types that support the value​0​. The exception is the typebool: even though division byfalse traps due to integral promotion frombool toint, it is the zero-valuedint that traps. Zero is not a value of typebool.

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 ofstd::numeric_limits<T>::traps for floating-point types reflects the state of floating-point trapping facility at the time of program startup, which isfalse on most modern systems. An exception would be aDEC Alpha program, where it istrue if compiled without-ieee.

[edit]Example

#include <iostream>#include <limits> int main(){std::cout<<std::boolalpha<<"bool:     traps = "<<std::numeric_limits<bool>::traps<<'\n'<<"char:     traps = "<<std::numeric_limits<char>::traps<<'\n'<<"char16_t: traps = "<<std::numeric_limits<char16_t>::traps<<'\n'<<"long:     traps = "<<std::numeric_limits<long>::traps<<'\n'<<"float:    traps = "<<std::numeric_limits<float>::traps<<'\n';}

// GCC output:bool:     traps = truechar:     traps = truechar16_t: traps = truelong:     traps = truefloat:    traps = false // Clang output:bool:     traps = falsechar:     traps = truechar16_t: traps = truelong:     traps = truefloat:    traps = false

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit]See also

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