Defines a type that can be used to represent a set of constant values or any combination of those values. This trait is typically implemented by integer types, std::bitset
Requirements
The bitmask type supports a finite number of bitmask elements, which are distinct non-zero values of the bitmask type, such that, for any pair Ci and Cj, Ci & Ci is nonzero and Ci & Cj is zero. In addition, the value 0
The bitwise operators operator&, operator|, operator^, operator~, operator&=, operator|=, and
operator^=
The following expressions are well-formed and have the following meaning for any BitmaskType:
| X |= Y
|
sets the value Y in the object X
|
| X &= ~Y
|
clears the value Y in the object X
|
| X & Y
|
nonzero result indicates that the value Y is set in the object X
|
Each representable bitmask element is defined as an inline(since C++17)
constexpr
Standard library
The following standard library types satisfy BitmaskType:
Code that relies on some particular implementation option (e.g.
int n =
std::ios_base::hex
) is non-portable because std::ios_base::fmtflags is not necessarily implicitly convertible to int