# How to check if a 64\-bit project is being built in Visual Studio using \#ifdef

You may easily do it using \#define preliminarily defined in the compiler\. The following is the code that shows in what mode a project is being built – 32\-bit mode or 64\-bit mode \(AMD64 or Intel 64\) or in Itanium mode\.

```cpp
#if defined _M_IX86
      cout << _T(" (x86)");
#elif defined _M_X64
      cout << _T(" (x64)");
#elif defined _M_IA64
    cout << _T(" (Itanium)");
#endif
```

## References

1. Predefined Macros\. [https://msdn\.microsoft\.com/en\-us/library/b0084kay\(v\=vs\.80\)\.aspx](https://www.microsoft.com/en-us/download/details.aspx?id=55984)