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struct in Background C program


JeffB
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My single file background c program was getting unwieldy so I decided to split it into 1 header and 3 c files. Now I get some strange errors saying my struct is not defined. So I copied my struct to the capp sample program header file and it also didn’t work. Then I defined my struct within the capp.c file and it did compile. What am I missing?

__________

/*For more information see notes.txt in the Documentation folder */

#include

 

#define _PPScriptMode_· · // for enum mode, replace this with #define _EnumMode_

#include "../../Include/pp_proj.h"

 

//#include "capp1.h"

 

typedef unsigned long DWORD;

 

typedef struct _SStatus

{

· union {

· · struct {

· · · DWORD abUnusable : 8;

· · · DWORD bMotionBusy : 1; //0b23

· · · DWORD bInitializeEnd : 1; //0b22

· · · DWORD bAllServoOn : 1; //0b21

· · · DWORD bAlarm : 1; //0b20

· · · DWORD bHomePosition : 1; //0b19

· · · DWORD bStandbyPosition : 1; //0b18

· · · DWORD bExchangePosition : 1; //0b17

· · · DWORD bSystemReady : 1; //0b16

· · · DWORD abUnused :16;

· · };

· · DWORD dwStatus;

· };

} SStatus;

 

int main(void)

{

· InitLibrary(); // Required for accessing Power PMAC library

 

· · · · · //Put your code here

· SStatus status;

· status.bMotionBusy = true;

 

· CloseLibrary();

· return 0;

}

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You can move your structure definition to a .h file. Here is my example which sets P0=12 through the member of a structure defined in structs.h.

 

capp1.c

/*For more information see notes.txt in the Documentation folder */
#include 

#define _PPScriptMode_		// for enum mode, replace this with #define _EnumMode_
#include "../../Include/pp_proj.h"
#include "structs.h"

int main(void)
{
InitLibrary();  // Required for accessing Power PMAC library

struct AStruct MyStruct;
MyStruct.MyVar1=12;
pshm->P[0]=MyStruct.MyVar1;

CloseLibrary();
return 0;
}

 

structs.h

typedef struct AStruct
{
double MyVar1;
double MyVar2;
};

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Thanks for the reply, Eric.

 

So if in the same c file I can use the format

typedef struct _SStatus

{

}SStatus;

 

but if in a header file this doesn't work but

typedef struct SStatus

{

};

 

does work. What about my typedef unsigned long DWORD;? That also works fine when everything is in a .c file. How to make that work in the .h file?

 

I attached a simple sample of my issues. The forum said the .h file type wasn't allowed so I renamed to .txt. I put the same code in one file and in the header file. It will compile as is but if you comment out the 2 typedefs in the .c file and rely on the definitions in the header it won't compile.

 

If there's a sample of some more complicated program I could glean the compile rules from that would be ideal. Or maybe I'm doing something fundamentally wrong -- it seems strange to me that the same code should be handled differently in header and c file.

 

Thanks!

capp1.c

capp1.txt

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  • 2 weeks later...

In case anybody else runs into this, if the struct is defined in a header file, its format should be typedef struct Name{definition}Name;

Both Names must be the same and both must be present.

 

If the struct is in the .c file it can be declared more flexibly.

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