Question

typedef struct
{   
    int A;
    int B;

    char* C; // problem is here
}foo;

int SetA(void)
{
    ....
    return retval;
}

int SetB(void)
{
    ....
    return retval;
}

const char* bar(void)
{
    .....
    char* retval="return val";
    .....
    return retval;
}

void SetFoo(foo* paramFoo)
{
paramFoo->A = SetA();
paramFoo->B = SetB();

paramFoo->C = bar();

}


static foo staticFoo;

void main()
{   
    SetFoo(&staticFoo);
    printf("%s",staticFoo.C);// printing
}

everything will go fine but the “char*C” in struct foo will not be written well. why? i need to know if i did mistake and how too correct it?. i’ve ran the bar() and it returns the correct value.

Thank you
~ Max

Answer 1

I would prefer using malloc and later free it, so that I dont have to worry about when the read only string literal get destroyed.

 const char* bar(void) 
 {     
     const char* retval="return val";
     char * value = malloc( strlen(retval) + 1 ); // +1 for the termination 
                                                  // character
     strcpy( value, retval );
     retrun value ;
 }

Remember to free the return value when no longer needed.