the colon (:) in a struct

[Scott Allen]

Hello,

I'm doing some maintenance on some C++ code and I ran across this
struct:

struct datetype
{
unsigned short day : 5;
unsigned short month : 4;
unsigned short year : 7;
};


Can anyone tell me what the : is doing? I think that defines the size
in bits, but I'm not sure.

Thank you, -Scott

 

[Victor Bazarov]

I'm doing some maintenance on some C++ code and I ran across this
struct:

struct datetype
{
unsigned short day : 5;
unsigned short month : 4;
unsigned short year : 7;
};


Can anyone tell me what the : is doing? I think that defines the size
in bits, but I'm not sure.

Yes, it does. It's basically inherited from C. Look up "bit fields"
in your favourite C book.

Victor