std::max_align_t

 

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Fixed width integer types(C++11)
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ptrdiff_t size_t max_align_t (C++11)     byte (C++17)	nullptr_t (C++11) offsetof NULL
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type_info type_index (C++11)	bad_typeid bad_cast

 

Defined in header <cstddef>
typedef/* implementation-defined */ max_align_t;		(since C++11)

std::max_align_t is a standard-layoutTrivialType(until C++26)TriviallyCopyable type(since C++26) whose alignment requirement is at least as strict (as large) as that of every scalar type.

std::is_trivially_default_constructible_v<std::max_align_t> is true.

Notes

Pointers returned by allocation functions such as std::malloc are suitably aligned for any object, which means they are aligned at least as strictly as std::max_align_t.

Example

Run this code

#include <cstddef>#include <iostream>   int main(){std::cout<< alignof(std::max_align_t)<<'\n';}

Possible output:

16

References

• C++23 standard (ISO/IEC 14882:2024):

• 17.2.4 Sizes, alignments, and offsets [support.types.layout] (p: 504-505)

• C++20 standard (ISO/IEC 14882:2020):

• 17.2.4 Sizes, alignments, and offsets [support.types.layout] (p: 507-508)

• C++17 standard (ISO/IEC 14882:2017):

• 21.2.4 Sizes, alignments, and offsets [support.types.layout] (p: 479)

• C++14 standard (ISO/IEC 14882:2014):

• 18.2 Types [support.types] (p: 443-444)

• C++11 standard (ISO/IEC 14882:2011):

• 18.2 Types [support.types] (p: 454-455)

See also

alignof(C++11)	queries alignment requirements of a type (operator)
alignment_of (C++11)	obtains the type's alignment requirements (class template)
is_scalar (C++11)	checks if a type is a scalar type (class template)
C documentation for max_align_t