Question

I am looking into the code written by other members and I came across the code shown below:

struct myType
{
 int   myInt  : 1;
 int   reserved : 31;
};

What is 1 and 31 stands above and when above notation is used?

Answer 1

These are bit fields. This code means, that myInt is just one bit and reserved is 31 bits

For example, on my machine

struct a
{
    int asd : 1;
    int b : 2;
};

std::cout << sizeof( a );

prints 4 (it’s platform dependent). In you’re example, the exact size of the struct is 32bits, but it’s possible the actual size to be different – depends on the alignment