#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>

#include "info.h"

int main()
{
    int  id;
    struct info *ctrl;
    
	id = shmget( KEY,MSIZ, 0 );
	// get the id of the already created shared memory segment
	// .. function to create is same as getting id of the already created shared memory segment
	if ( id < 0 )
    	{
		//error … ; 
		exit(1) ; 
	}
   
  	// attach a local pointer to the shared memory
  	 ctrl = (struct info *) shmat( id, 0, 0);
	if ( ctrl <= (struct info *) (0) )
    	{
		//error … ; 
		exit(1) ;
	}

    while (ctrl->flag!=-1)
    {
    	// if flag is 1, add the numbers from shared memory, set flag to 0
		if (ctrl->flag==1)
		{
			ctrl->sum = ctrl->value1+ctrl->value2;
			printf("Sum: %f + %f = %f\n", ctrl->value1, ctrl->value2, ctrl->sum);
			ctrl->flag = 0;
		}
    }
   
   	//detach the pointer from the shared memory 
   	// .. we do not need to delete here, can be done in either of the process
   	shmdt(ctrl);
   	exit(0);
}