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title: "alignof and alignas (C++) | Microsoft Docs"
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# alignof and alignas (C++)
The `alignas` type specifier is a portable, C++ standard way to specify custom alignment of variables and user defined types. The `alignof` operator is likewise a standard, portable way to obtain the alignment of a specified type or variable.  
  
## Example  
 You can use `alignas` on a class, struck or union, or on individual members. When multiple `alignas` specifiers are encountered, the compiler will choose the strictest one, (the one with the largest value).  
  
```cpp  
// alignas_alignof.cpp
// compile with: cl /EHsc alignas_alignof.cpp
#include <iostream>

struct alignas(16) Bar  
{      
    int i;       // 4 bytes  
    int n;      // 4 bytes  
    alignas(4) char arr[3];  
    short s;          // 2 bytes  
};  

int main()
{  
    std::cout << alignof(Bar) << std::endl; // output: 16  
}  
```  
  
## See Also  
 [Alignment](../cpp/alignment-cpp-declarations.md)