How to do global pointers to struct in "C"?

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Any help is greatly appreciated.
I have four files pasted below. when I try to compile with this command:
gcc -o test Test.c main.c

Got these errors:
In file included from Test.h:4,
from Test.c:1:
Types.h:9:7: warning: no newline at end of file
Test.c:9: error: syntax error before "Status"
In file included from Test.h:4,
from main.c:1:
Types.h:9:7: warning: no newline at end of file
main.c: In function `main':
main.c:6: error: `Status_Ptr_In_Header' undeclared (first use in this function)
main.c:6: error: (Each undeclared identifier is reported only once
main.c:6: error: for each function it appears in.)

main.c:

C

#include "Test.h"

int main(void)
{
	Status * Status_Ptr;
	Status_Ptr = (Status *) Status_Ptr_In_Header;

	int xx = (int)(&Status_Ptr->Status_1);

	printf("Status_Ptr->Status: %d", xx);
	printf("This is main.");

	return 1;
}

Test.h:

C

#ifndef TEST_H
#define TEST_H
#include "Types.h"

typedef struct STATUS_STRUCT {
	Status_Enum Status_1;
	Status_Enum Status_2;
	Status_Enum Status_3;
}Status;

extern Status * Status_Ptr_In_Test;

#endif

Test.c:

C

#include "Test.h"

Status MyStatus = {
	STATUS_ONE,
	STATUS_ONE,
	STATUS_ZERO
};

(Status *)Status_Ptr_In_Test = &MyStatus;

C

Types.h:

#ifndef TYPES_H
#define TYPES_H

typedef enum STATUS_ENUM{
	STATUS_ZERO = 0,
	STATUS_ONE = 1
}Status_Enum;

#endif

Posted 27-Aug-12 3:25am

Tikot123

Updated 27-Aug-12 3:34am

fjdiewornncalwe

v3

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Comments

[no name] 27-Aug-12 9:36am

The title of your question and the contents have nothing to do with each other.

Tikot123 27-Aug-12 10:27am

One of the error is
main.c:6: error: `Status_Ptr_In_Header' undeclared (first use in this function).
I thought using the term "extern" should make the pointer global. Hence the title.

Tikot123 27-Aug-12 10:37am

All the errors in main.c are resolved. In function `main' I changed:
`Status_Ptr_In_Header' to 'Status_Ptr_In_Test'.

1 solution

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Philip Stuyck · Answer 1 · 2012-08-27T03:39:00

Solution 1

The code in test.c is a bit crappy.
Solve one error after the other.

What it boils down to is this :

CSS

Status MyStatus = {
STATUS_ONE,
STATUS_ONE,
STATUS_ZERO
};

What are you trying to do here ? Create an an array or enum ?
My guess is here is that it is suppused to be an array right ?
Then it should be :
Status Mystatus[] = {STATUS_ONE, STATUS_ONE, STATUS_ZERO};
this is also fine :
Status Mystatus[3] = {STATUS_ONE, STATUS_ONE, STATUS_ZERO};
But actually the first method is better, because if you add an element you don't have to change the 3 into a 4, the compiler finds out how many elements are in the array

I actually see a lot more errors because for instance in main.c you do
Status_Ptr = (Status *) Status_Ptr_In_Header;
and Status_Ptr_In_Header is never declared. What you need here is this to change it into Status_Ptr_In_Test;

Posted 27-Aug-12 3:39am

Philip Stuyck

Updated 27-Aug-12 3:44am

v2

Comments

Tikot123 27-Aug-12 9:42am

I wanted to initialize the struct "Status" which is a typedef of STATUS_STRUCT .

Philip Stuyck 27-Aug-12 9:45am

Status is a type and cannot be initialised, only variables are initialised. You are trying to initialise myStatus.

Tikot123 27-Aug-12 10:27am

Sorry... your correct. My bad.

Tikot123 27-Aug-12 10:35am

All the errors in main.c are resolved. In function `main' I changed:
`Status_Ptr_In_Header' to 'Status_Ptr_In_Test'.

Philip Stuyck 27-Aug-12 10:48am

If it works please mark me as solution.

Tikot123 27-Aug-12 11:25am

How do I "mark me" (which is you) as solution. Please advise. Thx

Tikot123 27-Aug-12 11:30am

The error left is the error(in the original question/comment):
Test.c:9: error: syntax error before "Status".

Philip Stuyck 28-Aug-12 4:22am

Can you update your question with the code changes that you have done so far plse ?