LNK1169 & LNK2005

[jrfrago]

where do we properly declare global variables?
I always get this LNK1169 & LNK2005 when I declare a variable to be global. I have 4 cpp and 4 h files.

[Chillieman]

Lets take an example. We want an "int i" in all 4 cpp files

One header needs to have this snipit of code

extern int i;

Include that header in ALL 4 cpp files

ONE cpp file can have this snipit

int i = 1

You can now call i in all 4 cpp files

//Remember that you can only initialize a variable once, so "int i = 1" can only appear once, Any time after that, you need to alter it like "i = 10"

Hope i was clear enough

[andywestken]

Srictly speaking, the rule is that you are allowed to define a variable (or function) just the once: the "One definition rule".
http://en.wikipedia.org/wiki/One_Definition_Rule

You will still get a problem if you have int i; (rather than extern int i;) in a header, irrespective of whether you inititialize the variable at the point you define it.

Andy

LNK1169 one or more multiply defined symbols found
LNK2005 symbol already defined in object

[Chillieman]

Thank you for iterating on what i stated, thats the point i was trying to get at.

You can DECLARE a variable numerous times, in all the files you want to include (extern int i;)

but you can only DEFINE a variable once. (int i;)


Not too good on the grammer, better on the practice

[jrfrago]

I guess it was never defined, only declared....