Unresolved Symbols Remain

David Muller1

Hi there,

I'm having some trouble, and I think it's with C syntax... I have a header file "System.h" which is included by multiple c source files (call them foo.c, bar.c).

I'd like to define a struct "alpha" in System.h, and a global variable whose type is alpha in that header as well. I'm not sure if global is the right word here...I'd just like to define a variable whose type is alpha that I can access and modify in foo.c and bar.c.

This is what I have:

"System.h"

struct alpha

{

int a;

int b;

};

extern struct alpha myNewVariable;

"foo.c"

myNewVariable.a = 5;

"bar.c"

myNewVariable.b = 7;

CCS gives me the following error:

error #10234-D: unresolved symbols remain
error #10010: errors encountered during linking; "SeapHOX_source_files.out" not
built

What kind of error is this? How can I fix my declarations? Thanks!

-David

over 12 years ago

0 AartiG over 12 years ago

TI__Guru**** 173310 points

The structure should be declared as extern in the header file and then "defined" once in one of the C source files.

So in either foo.c or bar.c, you should define the variable with:
struct alpha myNewVariable;

The you can reference it in other source files.

0 David Muller1 over 12 years ago in reply to AartiG

Prodigy 220 points

Ok, I have

"System.h"

extern struct alpha

{

int a;

int b;

};

Then in foo.c (above my main) I have: struct alpha myNewVariable;

But, then CCS tells me that identifier "myNewVariable" is undefined in bar.c.

What's still wrong here?

Sorry, I'm pretty new to this stuff, and really appreciate all your help. Thanks!

-David

0 AartiG over 12 years ago in reply to David Muller1

TI__Guru**** 173310 points

Did you make sure to #include "system.h" in both C files?

I tried the following and it builds fine:

system.h
------------

struct alpha
{
int a;
int b;
};

extern struct alpha myNewVariable;

foo.c
-------

#include "system.h"
struct alpha myNewVariable;

main()
{
myNewVariable.a = 5;
}

bar.c
------

#include "system.h"

bar()
{
myNewVariable.b = 7;
}

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Unresolved Symbols Remain