external and static in c
Posted: Mon Jan 26, 2009 12:29 pm
Does anyone know what the result is of declaring a variable or function static external? What about external static?
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external and static in c
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Re: external and static in c
Posted: Mon Jan 26, 2009 12:56 pm
Does that even work? They are both linkage declarations so I figure they would conflict and the compiler won't compile the code.
Re: external and static in c
Posted: Mon Jan 26, 2009 1:00 pm
Yes they both work, but I dont know the difference, but there is a difference. External means global and static means local, so together they should conflict but I think it has a special meaning.
Re: external and static in c
Posted: Mon Jan 26, 2009 10:51 pm
hey, im asking the questions here. dont look to me for explanation. What would two opposite keywords make combined?
Re: external and static in c
Posted: Mon Jan 26, 2009 10:57 pm
Berkus' post is a link...yemista wrote:hey, im asking the questions here. dont look to me for explanation. What would two opposite keywords make combined?
Re: external and static in c
Posted: Mon Jan 26, 2009 11:00 pm
Do you even know what those keywords mean?
Re: external and static in c
Posted: Tue Jan 27, 2009 12:35 am
. If a function is declared as static it cannot be referenced externally , what's the point of your question ?Regards
Shrek
Re: external and static in c
Posted: Tue Jan 27, 2009 12:49 am
EDIT: Shrek explains it better below. This post was full of grammatical fail.
Re: external and static in c
Posted: Tue Jan 27, 2009 10:28 am
Hi,
extern is used to denote symbols that are not present the current object file and its the duty of the linkage editor (linker ) , to find out the symbol from a different module .
static has two meanings
when used for a variable : The variable maitains its values between function calls , just to give a demonstration , type this program in and find out the output
when used for a function :
when used for a function it means that , function has scope restricted to the given file . It provides some sort of isolation .
However all these are very basic and should not be asked at this level
.I now really understand Alboin's and Solar's sentiments. Please read a good C book , then your questions will make more sense .
Regards
Shrek
extern is used to denote symbols that are not present the current object file and its the duty of the linkage editor (linker ) , to find out the symbol from a different module .
static has two meanings
when used for a variable : The variable maitains its values between function calls , just to give a demonstration , type this program in and find out the output
Code: Select all
#include <stdio.h>
#include <stdlib.h>
void func();
int main()
{
func();
func();
func();
}
void func()
{
static int var = 0 ;
var++;
printf("%d \n " , var );
}
when used for a function it means that , function has scope restricted to the given file . It provides some sort of isolation .
However all these are very basic and should not be asked at this level
.I now really understand Alboin's and Solar's sentiments. Please read a good C book , then your questions will make more sense .Regards
Shrek
Re: external and static in c
Posted: Tue Jan 27, 2009 2:12 pm
Doesn't she mean what they mean together? Something like
Which won't compile.
P.S.: I believe I've just advertised foobar2000.
Code: Select all
extern static int foobar;
P.S.: I believe I've just advertised foobar2000.
Re: external and static in c
Posted: Tue Jan 27, 2009 2:48 pm
Yes I do mean together. And its he. If extern static int foobar wont compile, static extern int foobar will, and Im wondering what that means.
Re: external and static in c
Posted: Tue Jan 27, 2009 2:51 pm
Ok it looks like it wont compile. I dont know wat I was thinking of, but as soon as I find that example ill put it up.
Re: external and static in c
Posted: Tue Jan 27, 2009 3:48 pm
The point is, what the hell does gcc do when you declare the same symbol as both extern and static?Shrek wrote:
This code is absolute nonsense, yet it compiles cleanly with gcc 4.3.2. At the very least it's nonsense that "static int oups; extern int oups;" compiles while "static extern int oups;" does not.
#include <stdio.h>
static int oups;
extern int oups;
int main (int argc, char *argv[]) {
printf("%d, %d", argc, oups);
return 0;
}
Re: external and static in c
Posted: Tue Jan 27, 2009 5:51 pm
well i guess it does work then
Re: external and static in c
Posted: Tue Jan 27, 2009 5:52 pm
Why doesn't my code compile?
I don't understands!
Kthx.
Code: Select all
const volatile int a = 3.1415f;Kthx.