rosserial, multiple callbacks and interrptions?

edit

Hello, I am new to rosserial. The objective of this program is to make a LED (pin 13) blink with a Period=5s, and then exit this blinking.

Thus, after connecting ROS to Arduino via USB, I apply a 'toggle_msg" to initiate the process (which runs perfectly), and my will is that the process ends when I apply a "end_msg" message. Each message has its own callback function as you can see.On the ROS terminal I apply each message this way:

rostopic pub toggle_led std_msgs/Empty --once

rostopic pub end_led std_msgs/Empty --once

The problem is that I do not know how to exit the while loop in the first callback, and the process really never ends. How can I do this?

The code is here:

# include <ros.h>
# include <std_msgs/Empty.h>

 int k=0;     


ros::NodeHandle  nh;

void messageCb( const std_msgs::Empty& toggle_msg){        

  while(k==0){

  digitalWrite(13, HIGH-digitalRead(13)); 

  delay(5000); 


}

}

void messageCb1( const std_msgs::Empty& end_msg){                 
k=1;
delay(1000);
}

ros::Subscriber<std_msgs::Empty> sub("toggle_led", &messageCb );   
ros::Subscriber<std_msgs::Empty> sub1("end_led", &messageCb1 );


void setup()
{ 

  pinMode(13, OUTPUT);
  nh.initNode();
  nh.subscribe(sub);                                              
  nh.subscribe(sub1);
}

void loop()
{  
  nh.spinOnce();                                                    
  delay(1);
}

THANKS!!!