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

std::max_align_t is a trivial standard-layout type whose alignment requirement is at least as strict (as large) as that of every scalar type.


[edit] 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.

std::max_align_t is usually synonymous with the largest scalar type, which is long double on most platforms, and its alignment requirement is either 8 or 16.

[edit] Example

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

Possible output:


[edit] References

  • 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)

[edit] See also

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