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Bit flags for C++ scoped enums

C++ 11 added a new type of enums — enum classes. These are strongly typed enumerations, they do not cast implicitly to or from the underlying integer type. They also do not leak enumeration values to enclosing scope (thus the names of this values do not clash and you no longer need to prefix/suffix them with something to disambiguate).

The only drawback to type safety is you cannot treat variables of enum class types as sets of flags. That is because enum classes do not cast to integers and there are no bitwise operators overloads defined for them.

This library brings a flags class template which provides bit flags for scoped enums.


Using Conan

Add required remote:

$ conan remote add grisumbras

Use inside conanfile.txt:


Installing from source

Download source code and run from inside the project root:

$ b2 install --prefix=/path/to/installation/prefix


#include <flags/flags.hpp>

enum class MyEnum { Value1 = 1 << 0, Value2 = 1 << 1 };

int main() {
  auto mask1 = MyEnum::Value1 | MyEnum::Value2; // set flags Value1 and Value 2
  if (mask1 & MyEnum::Value2) { // if Value2 flag is set
    /* ... */

More info can be found in the docs.


Dmitry Arkhipov


Patches welcome!


MIT (C) Dmitry Arkhipov.