std::endian

 

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Endian

endian (C++20)

 

Defined in header <bit>
enumclass endian {     little =/* implementation-defined */,     big    =/* implementation-defined */,     native =/* implementation-defined */, };		(since C++20)

Indicates the endianness of all scalar types:

• If all scalar types are little-endian, std::endian::native equals std::endian::little.
• If all scalar types are big-endian, std::endian::native equals std::endian::big.

Corner case platforms are also supported:

• If all scalar types have sizeof equal to 1, endianness does not matter and all three values, std::endian::little, std::endian::big, and std::endian::native are the same.
• If the platform uses mixed endian, std::endian::native equals neither std::endian::big nor std::endian::little.

Possible implementation

enumclass endian {#if defined(_MSC_VER) && !defined(__clang__) little =0, big =1, native = little #else little = __ORDER_LITTLE_ENDIAN__, big = __ORDER_BIG_ENDIAN__, native = __BYTE_ORDER__ #endif};

Notes

Feature-test macro	Value	Std	Feature
__cpp_lib_endian	201907L	(C++20)	std::endian

Example

Run this code

#include <bit>#include <iostream>   int main(){ifconstexpr(std::endian::native== std::endian::big)std::cout<<"big-endian\n";elseifconstexpr(std::endian::native== std::endian::little)std::cout<<"little-endian\n";elsestd::cout<<"mixed-endian\n";}

Possible output:

mixed-endian

See also

byteswap (C++23)	reverses the bytes in the given integer value (function template)
C documentation for endian