scope resolution operator

[heng]

A::B
I can understand that B is a member of the scope A
But, sometimes I read the expression like ::C, what does this mean when
the scope is absent?
Thanks.

 

[Victor Bazarov]

A::B
I can understand that B is a member of the scope A
But, sometimes I read the expression like ::C, what does this mean
when the scope is absent?

It means "global".

V

 

[Howard]

A::B
I can understand that B is a member of the scope A
But, sometimes I read the expression like ::C, what does this mean when
the scope is absent?
Thanks.

That's "global scope". (Or is it "global namespace"? I forget.) It's used
to differentiate it from an identically named function or object in the
current scope. For example, there is the global function strcpy(). It is
possible (though perhaps not adviseable) that you have a class (or
namespace) which implements a function also named strcpy(). Using ::strcpy
from inside a function of that class or namespace would mean you're caling
the global strcpy() instead of your class' or namespace's strcpy().

-Howard

 

[heng]

Thanks a lot.

That's "global scope". (Or is it "global namespace"? I forget.) It's used
to differentiate it from an identically named function or object in the
current scope. For example, there is the global function strcpy(). It is
possible (though perhaps not adviseable) that you have a class (or
namespace) which implements a function also named strcpy(). Using ::strcpy
from inside a function of that class or namespace would mean you're caling
the global strcpy() instead of your class' or namespace's strcpy().

-Howard

 

[Default User]

Thanks a lot.

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