07-27-2023, 11:53 AM
I am learning C. In _C Primer Plus_, I saw an bit field example as follows:
struct box_props {
bool opaque : 1;
unsigned int fill_color : 3;
unsigned int : 4;
bool show_border : 1;
unsigned int border_color : 3;
unsigned int border_style : 2;
unsigned int : 2;
};
I do understand the 4-bit unnamed bit field in the middle is used for letting the following bits start at a new byte. However, I don't understand why there is another unnamed bit field at the end of the structure. What's the purpose of it? Is it necessary?
struct box_props {
bool opaque : 1;
unsigned int fill_color : 3;
unsigned int : 4;
bool show_border : 1;
unsigned int border_color : 3;
unsigned int border_style : 2;
unsigned int : 2;
};
I do understand the 4-bit unnamed bit field in the middle is used for letting the following bits start at a new byte. However, I don't understand why there is another unnamed bit field at the end of the structure. What's the purpose of it? Is it necessary?