declaring a struct in .h file and implementing in .c file

Question

this is my .h file:

struct _MyString;  
typedef struct _MyString MyString;

i would like to declare its members in the .c file.

i tried:

typedef struct MyString{
    char * _str;// pointer to the matrix
    unsigned long _strLength;
    }MyString;

but it doesn't work. how do i declare the struct's memebers in the .c file?

thank you

Answer 1

You need only 1 typedef. Keep the one you already have in the .h file and delete all others.

Now, the struct name is struct _MyString. That is what you should define in the .c file, not struct MyString: notice the absence of the '_'.

So

.h file

struct _MyString;  
typedef struct _MyString MyString;

.c file

#include "file.h"
struct _MyString {
    char * _str;// pointer to the matrix
    unsigned long _strLength;
};