Question

I am trying to copy a structure x into another structure y that has x nested.

For example:

#define DATASIZE 128

typedef struct {
        char data[DATASIZE];    
} x_TYPE;


typedef struct {
    int               number;  
    x_TYPE            nested_x;     
    enum boolean      error;     
} y_TYPE;

/* ---- Values for the type field in xy_union ---- */
#define TYPE_IS_X 0;
#define TYPE_IS_Y 1;

typedef struct {
    union {                       /* structure containing x_object */
           x_TYPE      x_object; /*        or y_object as a union */
           y_TYPE      y_object;
    } u;
int type;            /*One of: TYPE_IS_X, TYPE_IS_Y */

} XY_TYPE;

This is how I currently copy:

copyXY(XY_TYPE *xx)
{
   XY_TYPE *yy; /* assume this is allocated already */


    yy->u.y_object.nested_x = *xx; /* ERROR LINE */


   return 0;
}

I get a compiler error of: error: incompatible types when assigning to type ‘x_TYPE’ from type ‘XY_TYPE’.

Please let me know if anyone knows why this occurs.

Answer 1

Is this what you are looking for?

XY_TYPE *yy; /* assume this is allocated already */

void copyXIntoYY(XY_TYPE *xx)
{
    yy->u.y_object.nested_x = xx->u.x_object;
}

It isn’t clear from the question what you are trying to do.