# max_align_t

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< c‎ | types

Defined in header `<stddef.h>` |  |
typedef /*implementation-defined*/ max_align_t; |  | (since C11)

max_align_t is a type whose alignment requirement is at least as strict (as large) as that of every scalar type.

### Notes

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

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.

### Example

Run this code

    #include <stdio.h>
    #include <stddef.h>
    #include <stdalign.h>
    #include <stdlib.h>
    #include <stdint.h>
    #include <inttypes.h>

    int main(void)
    {
        size_t a = alignof(max_align_t);
        printf("Alignment of max_align_t is %zu (%#zx)\n", a, a);

        void *p = malloc(123);
        printf("The address obtained from malloc(123) is %#" PRIxPTR"\n",
                (uintptr_t)p);
        free(p);
    }

Possible output:

    Alignment of max_align_t is 16 (0x10)
    The address obtained from malloc(123) is 0x1fa67010

### References

- C17 standard (ISO/IEC 9899:2018):

  - 7.19 Common definitions <stddef.h> (p: 211)

- C11 standard (ISO/IEC 9899:2011):

  - 7.19 Common definitions <stddef.h> (p: 288)

### See also

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