title: How to get return value from CHILD PROCESS?
body: <p>Program calculates sum of numbers from 1 to N..
  Child process calculates sum of EVEN numbers.
  Parent process calculates sum of odd numbers.
  I want to get the return value of child process in parent process. How do i do that</p>
  
  <pre><code>#include&lt;stdio.h&gt;
  #include&lt;errno.h&gt;
  #include&lt;unistd.h&gt;
  #include&lt;stdlib.h&gt;
  #include&lt;fcntl.h&gt;
  
  int main()
  {
      int N;
      int id;
      int fd_result;;
  
      printf("Enter N till which you want the sum: \n");
      scanf("%d",&amp;N);
      if ((fd_result=creat("result", 600))== -1)
      {
          perror("Error creating file");
          exit(1);
      }
      if ((fd_result=open("result",O_TRUNC | O_RDWR)) == -1)
      {
          perror("Error Opening file");
          exit(1);
      }
      if ((id=fork())&lt;0)
      {
          perror("Error occurred forking....!");
          exit(errno);
      }
      if (id == 0)
      {
          int i;
          int sum=0;
          for (i=0;i&lt;=N;i=i+2)
              sum+=i;
          printf("Child sum: %d",sum);
          if (write(fd_result,&amp;sum,sizeof(int))==-1) perror("Error writing to file");
          _exit(0);
      }
  
  
      if (id &gt; 0)
      {
          int i;
          int sum=0;
          int sum_odd;
          for (i=1;i&lt;=N;i=i+2)
              sum+=i;
          lseek(fd_result,0,SEEK_SET);
          read(fd_result,&amp;sum_odd,sizeof(int));
          printf("\nThe sum is: %d",sum+(int)sum_odd);
      }
  
      close(fd_result);
      return 0;
  }
  </code></pre>
  
  <p>Pls tell me how do I get the return value of child process?</p>