Device node is being polled by ROS node

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Hi ,

I am new to ROS and I am trying to publish a topic for my camera.When I try to obtain frames from my camera,the process fails with EBUSY during VIDOIC_S_FMT or VIDIOC_REQBUF. While trying to debug this issue I noticed that the node is trying to poll my device node. Regardless of the type of device being used, the node tries to poll all the device node being opened in the program.

I have attached the sample code for my node.

#include<iostream>
#include<fcntl.h>
#include<ros/ros.h>
#include<stdio.h>

int ft = 0;

int main (int argc, char **argv)
{

    ros::init (argc, argv, "test");
    ros::NodeHandle node;
    ft = open("/dev/video0",O_RDWR,0);
    while(ros::ok())
    {

    } 
    return 0;
}

After launching the node(test_node), the log message in dmesg is

[19781.321976] The process name is test_node line 930 func vb2_fop_poll

Is this a known behaviour or is something wrong here?Can anyone kindly help me out. I am using ROS melodic.