Structs declared in @interface

Many headers from Apple, line the NSTableView, have structs declared containing flags:

Code:

typedef struct __TvFlags {
    unsigned int        allowsColumnReordering:1;
    unsigned int        allowsColumnResizing:1;
    unsigned int        oldDrawsGridFlag:1;
    unsigned int        allowsEmptySelection:1;
    unsigned int        allowsMultipleSelection:1;
    unsigned int        allowsColumnSelection:1;
    unsigned int        selectionType:2;
    unsigned int        changingLayout:1; // Unused
    unsigned int        compareWidthWithSuperview:2;
    unsigned int        delegateWillDisplayCell:1;
    ...
    unsigned int        delegateShouldEditTableColumn:1;
    unsigned int        delegateShouldSelectRow:1;
    unsigned int        delegateShouldSelectTableColumn:1;
    unsigned int        delegateSelectionShouldChangeInTableView:1;
    unsigned int        oldAutoresizesAllColumnsToFit:1;
    unsigned int        dataSourceSetObjectValue:1;
    unsigned int        selectionPostingDisableCount:7;
} _TvFlags;

This brings me 2 questions:

1.What is this ":1" (or ":2") at the end of each line? I've never seen this!
2.How can I then access this struct from inside object: _TvFlags.(~) or _TvFlags->(~) (dereferenced)

Thanks!

 

Thanks. I had never learned about it (beginner programmer)

Indeed. Sorry, I mean to use the struct itself like you concluded.

Means "something".

Ok, thanks for the comparison which clarified things.

I know they are private, and I do not intent to use this struct, just pointed it out. I will be using these struct's to flags in my classes.

Thank you chown33, everything is clear now.