Re: Questions about const

I was having linking errors when I put:

const LPCTSTR Main_window_name = _TEXT("Thingy_main_window");

in one file and

extern const LPCTSTR Main_window_name;

in another. I've since realised that this is because (in C++) consts
do not, by default, have external linkage. I've solved the problem by
inserting an "extern" in front of the first one. (LPCTSTR is
typedef'ed in the headers somewhere as a pointer to constant
"characters", and _TEXT is a macro to convert a string to the correct
form of characters.)

However, I still have a couple of nagging doubts. The first is, is it
OK to use consts both in and with typedefs? For instance, if I do:

typedef int i;
typedef const int ci;

then can I do whichever I choose of

const i b = 3;

and

ci c = 3;

to get a variable of type const int? I see from testing that

const ci d = 3;

is an error - including the consts twice.

My second question is that, normally, if one were to put "extern int
x;" in several files, you would need to also include a line "int x;"
in one of them. But with consts, it seems that every mention of them
can have the extern keyword. Is this correct?