flags_attribute_

#define flags_attribute_	(		namespace_name,
			enum_type
	)

#include <xtd.core/include/xtd/flags_attribute.h>

Provides the set attribute struct for enumerations helper.

Namespace

xtd

Library

xtd.core

Parameters

namespace_name	The name of the the namespace. Empty if no namespace.
enum_type	The name of the enum flags.

Remarks

This helper is created to facilitate to set the xtd::enum_set_attribute with the xtd::enum_attribute::flags atribute and the implementation of the following operators for enum flags:

Operator	Name
^=	Bitwise XOR assignment
&=	Bitwise AND assignment
|=	Bitwise OR assignment
+=	Addition assignment
-=	Subtraction assignment
	Bitwise XOR
&	Bitwise AND
|	Bitwise OR
+	Addition
-	Subtraction
~	Bitwise NOT

Warning

The helper as one limitiation :

• The enum's flags cannot be in a class or struct. The enum must be in the global namespace or in a namespace hierarchy. If the enum flags is in a class or struct, add operators manually and use xtd::enum_set_attribute to register the xtd::enum_attribute::flags attribute.

Examples

The following code show how to use flags_attribute_ helper.

#include <xtd/console>
#include <xtd/enum_class>
#include <xtd/environment>
#include <xtd/string>
 
using namespace xtd;
 
enum class text_styles {
  normal =    0b0,
  bold =      0b1,
  italic =    0b10,
  underline = 0b100,
  strikeout = 0b1000,
};
 
// Add text_style enum class flags operators and register flags attribute.
flags_attribute_(, text_styles);
 
// Only this operator is needed for text_styles enum class to be recognized by xtd::string::format().
template<> struct xtd::enum_register<text_styles> {
  explicit operator auto() const noexcept {return xtd::enum_collection<text_styles> {{text_styles::normal, "normal"}, {text_styles::bold, "bold"}, {text_styles::italic, "italic"}, {text_styles::underline, "underline"}, {text_styles::strikeout, "strikeout"}};}
};
 
auto main() -> int {
  console::out << string::format("{}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("0b{:b}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("0b{:B}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("{:d}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("{:D}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("{:g}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("{:G}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("0{:o}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("0{:O}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("0x{:x}", text_styles::bold | text_styles::italic) << environment::new_line;
  console::out << string::format("0x{:X}", text_styles::bold | text_styles::italic) << environment::new_line;
}
 
// This code produces the following output :
//
// saturday
// 0b101
// 0b101
// 5
// 5
// saturday
// saturday
// 05
// 05
// 0x5
// 0x5

Examples

enum_class_flags.cpp, enum_class_flags_introspection.cpp, and format_enum_class_flags.cpp.