Debug global variables in C with Eclipse

Question

inside ah I defined a struct and used extern Struct *struct to use an instance of this struct in other .c files and my main.c file.

Following this guide I click on the same icon but all I get is an empty window, where no variables are listed.

How do I fix this?

ah defines Queue:

typedef struct Queue
{
    int size;
    q_elem *root;
} Queue;

and

extern Queue **queue;

ac defines various functions queue-typical functions.

In bc I define

Queue **queue;

as variable and work on it with several functions. I work on the same **queue in my main.c file.

I use Eclipse 3.3.2 for Windows.

Answer 1

This is a problem with potentially two sources of error. 1 being type of declaration you are using, and 2 being the debugging environment you are using.

Addressing 2 first : In my environment, (a National Instruments compiler/debugger) when resources get tight, the debugger begins to do flaky things, like display an array of structs incorrectly as a single struct, etc. I saw this just yesterday after several hours of using my debugger. The solution is to shut down and restart the environment to reset and clear all debugger memory. All debuggers I have used are subject to this type of behavior.

Addressing 1 : First, the way you have your struct defined is not compilable. ie, the line:

q_elem *root;  

Needs to be:

struct q_elem *root;

That alone may fix your problem. But you might also try to create the instance of your struct a little differently. I have not seen how you are using it, but I assume you want to create an array of structs with extern linking (perhaps for the purpose of having project scope). If this is the case, try this:

//In header file:

typedef struct QUEUE
{
    int size;
    struct QUEUE *root;
}QUEUE;

extern QUEUE queue[10], *pQueue;  

Then:

//In .c file:

QUEUE queue[10], *pQueue;

int main(void)
{

    pQueue = &queue[0];

    //...

You now have a pointer to an array of QUEUE with project scope. Note that it does not allocate memory for access to the member *root , For some pointers (no pun intended) on how to do that, Look Here .