Converting Big-Endian network byte order to Little-Endian host byte order in Modern C++:

Before C++23, developers used compiler-specific intrinsics (_byteswap_ulong in MSVC or __builtin_bswap32 in GCC).

In C++23, std::byteswap is a standard, constexpr function in <bit>:

#include <bit>
uint32_t netPacketLength = 0x12345678;
uint32_t hostLength = std::byteswap(netPacketLength); // Evaluates to 0x78563412

Compiles directly to the native bswap x86 CPU instruction or REV on ARM!

Finally a standard, portable way to swap byte orders without preprocessor #ifdef macros.

Also check out std::endian::native == std::endian::little from <bit> for compile-time architecture checks.