Store cursor position in class object (ncurses c++) - c++

Question

I am using QTCreator to compile my c++ code and the <curses.h> library.
Let us say we have the following class definition (.h):
struct coordinateYX
{
int y;
int x;
coordinateYX(long int yPos, long int xPos);
coordinateYX() {}
}
class Rogue
{
private:
long int health;
coordinateYX heroPosition;
public:
long int getHealth();
void setHealth(long int initHealth);
void healthChange(long int vDelta);
coordinateYX getHeroPosition();
void setHeroPosition(coordinateYX hPos);
};
and (.cpp):
coordinateYX::coordinateYX(long int yPos, long int xPos) : y{yPos}, x{xPos} {}
long int Rogue::getHealth() {return health;}
void Rogue::setHealth(long int initHealth) {health = initHealth;}
void Rogue::healthChange(long int vDelta) {health += vDelta;}
coordinateYX Rogue::getHeroPosition() {return heroPosition;}
void Rogue::setHeroPosition(coordinateYX hPos)
{
heroPosition.y = hPos.y;
heroPosition.x = hPos.x;
}
In my main.cpp, I am trying to store the current cursor position into an instantiation of Rogue:
Rogue Hero;
getyx(stdscr, Hero.getHeroPosition().y, Hero.getHeroPosition().x);
But I always get an error:
using temporary as lvalue [-fpermissive]
It also shows this below as part of the error which is in the <curses.h> file
#define getyx(w, y, x) (y = getcury(w), x = getcurx(w))
Although I can simply store these values in another struct initialized in main.cpp, how can I store the x and y positions directly in the class data members?
Thank you.

Answer 1

The quickest solution would be to change getHeroPosition to return a reference instead of value:
coordinateYX& Rogue::getHeroPosition() {return heroPosition;}
The problem is here you are trying to assign to the Rogue position:
getyx(stdscr, Hero.getHeroPosition().y, Hero.getHeroPosition().x);
This is equivalent to:
Hero.getHeroPosition().y = getcury(stdscr);
Hero.getHeroPosition().x = getcurx(stdscr);
But getHeroPosition returns the position by value (it returns a copy, an rvalue). If you assign a value to that temporary copy it will just be lost. The solution is to assign to a reference to the actual Rogue position (an lvalue).
Alternatively, you can use your existing setPosition function:
coordinateYX position;
getyx(stdscr, position.X, position.Y);
Hero.setPosition(position);