这个程序返回最近一次图形操作结果状态直,有什么用处呢?

或者说具体用在哪里?

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
int main(void)
{
    int gdriver = DETECT, gmode, errorcode;
    initgraph(&gdriver, &gmode,"");
    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s
", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }
    line(0, 0, getmaxx(), getmaxy());
    getch();
    closegraph();
    return 0;
}