int s: 3 ; declaration in structure is possible

Code:

---

#include<stdio.h>
struct a
{
int s: 3;
};

int main()
{
struct a a1;
printf("%d \n",a1.s);
return 0;
}

---

is there any use by defining int s: 3; with this systax program is compiling and linking.

wts the inner secret of this systx int s:3

i can apreciate any replys

Google bit fields for that.

It's a bit field: C Bit Fields (C)

Thanks for your replys