warning 4510 with const member in struct

I write a code section as this 

struct My
{
const int a;
};

OK, then set the warning level

then I will got this 

c:usersluli1documentsvisual studio 2013projectsconsoleapplication3header1.h(4): error C2220: warning treated as error - no 'object' file generated
1>c:usersluli1documentsvisual studio 2013projectsconsoleapplication3header1.h(4): warning C4510: 'My' : default constructor could not be generated
1> c:usersluli1documentsvisual studio 2013projectsconsoleapplication3header1.h(2) : see declaration of 'My'
1>c:usersluli1documentsvisual studio 2013projectsconsoleapplication3header1.h(4): warning C4512: 'My' : assignment operator could not be generated
1> c:usersluli1documentsvisual studio 2013projectsconsoleapplication3header1.h(2) : see declaration of 'My'
1>c:usersluli1documentsvisual studio 2013projectsconsoleapplication3header1.h(4): warning C4610: struct 'My' can never be instantiated - user defined constructor required
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

The ways to stop this are list below 

1.

struct My
{
const int a;

My (int i):a(i){}
};

2.in the property->c++->advanced, set "disable specific warning" as 4510, there you go

3. in the .h file , put on the top 

#pragma warning (disable:4510), and note that if you have inlcude an .h file that has this definition is also OK

Actually, replacing the struct with class, it may be easier to understand.

You may encounter with the warning 4512, but it is another story... :)