pw_alignment

Oveview

Natural object alignment, guaranteed. Main docs: https://pigweed.dev/pw_alignment.

Classes
struct	pw::NaturallyAligned< T >

Typedefs
template<typename T >
using	pw::AlignedAtomic = std::atomic< NaturallyAligned< T > >

Functions
	pw::NaturallyAligned< T >::NaturallyAligned (const T &t)
template<class U >
	pw::NaturallyAligned< T >::NaturallyAligned (const U &u)
NaturallyAligned &	pw::NaturallyAligned< T >::operator= (T other)

Typedef Documentation

AlignedAtomic

template<typename T >

using pw::AlignedAtomic = typedef std::atomic<NaturallyAligned<T> >

Ensures the object held by std::atomic is naturally aligned. This enables the compiler to replace libcalls to atomic functions with native instructions when appropriate. AlignedAtomic is a convenience wrapper.

Example:

#include "pw_alignment/alignment.h"
 
pw::AlignedAtomic<std::optional<bool>> mute_enable{};

std::optional<bool> has a size of 2 but alignment of 1, which would normally lower to an __atomic_* libcall, but pw::NaturallyAligned in std::atomic tells the compiler to align the object to 2 bytes, which satisfies the requirements for replacing __atomic_* with native instructions.