Problem when trying to return union type variable from function

Hi all,

I have a problem when trying to return a union type variable from function. The union is defined in a header file called "Dummy.h" like that:

Code:

typedef union
{
        uint32_t A;
        uint32_t B;
} dummy_union;

In "Dummy.c", I declared a function called dummy_union() which just saves 0x55 and 0xFF to a "dummy_union" variable "X" and returns it.

Code:

#include "Dummy.h"

inline  dummy_union Dummy_Task(void)
{
dummy_union X;

X.A = 0x55;
X.B = 0xFF;

return X;
}

Furthermore, Dummy_caller() calls Dummy_Task() and stores its return to a new "dummy_union" variable "var1". Finally, the 2 members of "var1" are printed.

Code:

void Dummy_caller(void)
{
static dummy_union var1;

var1=Dummy_Task();

printf("member 1 of var1 is %u \n", var1.A);
printf("member 2 of var1 is %u \n", var1.B);
}

However, both printfs give 0xFF. Does anyone have any idea why?

Thanks!

The point of a union is that the different parts share storage, so you can only use one at a time.

Your assignment of .B overwrites your assignment of .A. If you want a struct, use a struct.


Quzah.

Thanks for the help!