Variable assigning Functions

I know this might sound stupid, but I want to use a function to assign my own data type..

Code:

---

#include <stdio.h>
#include <stdlib.h>

typedef unsigned char byte;

typedef struct {
 byte header[15];
 int a;
 int b;
 byte *data;
} MY_TYPE;

int my_function(MY_TYPE mt)
{
 

}

int main()
{
 int er;
 MY_TYPE a;

 er = my_function(a);
}

---

What I want is for my_function to return an integer value to indicate the functions success or failure. This I know how to do..

But I want my_function's My_TYPE mt, to be equal to the main's MY_TYPE a, after the function is called..

Here's my problem, I want to do it without making ANY of the variables GLOBAL.

Any help would be great..

I'm a little confused by what your saying, but I am going to assume, you want to assign MY_TYPE a values through my_function.

Since you pass my_function a pointer to MY_TYPE a, it should change the values within...

I may be getting this confused with Java, but have you tried to write your function yet? -- If you have did it not work?

It is as follows..

Code:

---

int my_function(MY_TYPE mt)
{
 mt = get_data();  //  A custom function that assigns the variables  of  mt from a file  No need to post that code, it is irrelevant to what I want.

 if((strcmp(mt.header, "###MY  TYPE###") != 0)
 {
  return -1; // Unsuccessful
 }
 else
 {
  return 0;  // Successful.. but I also want it to assign mt's value to main's a. As main's a is empty.
 }
}

---

Pass a pointer:

Code:

---

#include <stdio.h>
#include <stdlib.h>

typedef unsigned char byte;

typedef struct {
 byte header[15];
 int a;
 int b;
 byte *data;
} MY_TYPE;

int my_function(MY_TYPE *mt)
{
  *mt = get_data();
  // do other stuff here
}

int main()
{
 int er;
 MY_TYPE a;

 er = my_function(&a);
}

---

I suppose I should have done more research before posting..

pointers, duh, I am an idiot..

Thanks much for the help,