Now, my question is, if I want to print the value of i before calling the foo() function in the file2.c, what should I do in order to not to end up in the linker error?
// file2.c
Code:
#include <stdio.h>
#include "file.h"
i = 20; // treats as an altogether a new definition of i, implicitly adds int keyword before i
int main() {
i = 20; // multiple definition error
printf("%d\n", i);
foo();
printf("%d\n", i);
}
Last edited by royalibrahim; 03-27-2013 at 02:54 AM..
#include <stdio.h>
#include "file.h"
int i = 20; // treats as a altogether a new definition of i, implicitly adds int keyword before i
int main() {
i = 20;
printf("%d\n", i);
foo();
printf("%d\n", i);
}
If you have the "extern int i" declaration in your file.h then I do not see why you would still get the multiple definition error...because the i in file2.c inside main is unrelated to the i in file1.c inside foo which in turn is unrelated to the global i that is defined in file2.c.
You have to look at the way the different variables are setup in the segments to understand the linkages between them. The global i defined in file2.c lies in the data segment and is unrelated to the local i inside main within the file2.c which lies on the stack frame created for main...similarly the local i inside foo of file1.c lies in the stack frame created for foo and is unrelated to the global i or the i that is local to main...let me know if this helps or if i have managed to confuse you even more
You have to look at the way the different variables are setup in the segments to understand the linkages between them. The global i defined in file2.c lies in the data segment and is unrelated to the local i inside main within the file2.c which lies on the stack frame created for main...similarly the local i inside foo of file1.c lies in the stack frame created for foo and is unrelated to the global i or the i that is local to main...let me know if this helps or if i have managed to confuse you even more
Your analysis is incorrect. There are no versions of i which are local to a block (function or otherwise). All of those identifiers refer to the same externally-linked, global storage allocation.
Your analysis is incorrect. There are no versions of i which are local to a block (function or otherwise). All of those identifiers refer to the same externally-linked, global storage allocation.
Regards,
Alister
Thanks alister, but when you say so then why in file2.c, the identifier 'i' is not referring to the same externally-linked, global storage allocation as how the file1.c does? that is,
Code:
#include <stdio.h>
#include "file.h"
int main() {
printf("%d\n", i); // undefined reference to `_i'
foo();
printf("%d\n", i);
}
Why I have to allocate a memory for i (declaring an int i) in the global scope in file2.c to get rid of this problem?
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03-26-2013
