?
Solved

Some Questions on : process, poll, pollfd

Posted on 2001-09-12
3
Medium Priority
?
445 Views
Last Modified: 2006-11-17
Hi All
 
I have some questions :
 
1. Can I change the owner of the process? Suppose I execute a program.
    pid = 1234
    process owner = "x"
   
    then I fork the process.
    pid of child = 12345
 
    Now I kill the parent.(1234). parent of 1235 is "1" now (init process). but owner still remains the same.. "x". can I change it to y?
 
2. what does POLLHUP signify in poll system call? does somebody have a piece of code that can emulate this??? when will I get POLLHUP as in reevent member of pollfd structure?
 
3. what is the significance of events & revents members of pollfd??? any program that emulates "all/most of" the conditions of poll will be really great.
 
Regards
 
Ajay
0
Comment
Question by:avi_india
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 14

Accepted Solution

by:
chris_calabrese earned 300 total points
ID: 6477724
1.  Only processes running as uid 0 (i.e., 'root') can change their uid.
 This is done with the setuid() system call.

2.  According the poll() man page, it happens when you're trying to access a device that's been physically disconnected..

3.  The significance of event and revent is that these are the structures
used to pass the list of things you want to poll for and where you find
out what actually happened respectively.

Don't have any code, but check the man pages.  The man page for poll
has excellent examples on every system I've seen.
0
 

Author Comment

by:avi_india
ID: 6478440
Thanks Chris....

About 2nd point my main concern is that in real scenario when this actually would happen??? i.e. if I've made a poll call, then when will I get POLLHUP?

0
 
LVL 14

Expert Comment

by:chris_calabrese
ID: 6480075
Say you're reading a file on a CD-ROM and someone ejects the CD...
0

Featured Post

Enroll in August's Course of the Month

August's CompTIA IT Fundamentals course includes 19 hours of basic computer principle modules and prepares you for the certification exam. It's free for Premium Members, Team Accounts, and Qualified Experts!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In tuning file systems on the Solaris Operating System, changing some parameters of a file system usually destroys the data on it. For instance, changing the cache segment block size in the volume of a T3 requires that you delete the existing volu…
Why Shell Scripting? Shell scripting is a powerful method of accessing UNIX systems and it is very flexible. Shell scripts are required when we want to execute a sequence of commands in Unix flavored operating systems. “Shell” is the command line i…
Learn several ways to interact with files and get file information from the bash shell. ls lists the contents of a directory: Using the -a flag displays hidden files: Using the -l flag formats the output in a long list: The file command gives us mor…
Learn how to navigate the file tree with the shell. Use pwd to print the current working directory: Use ls to list a directory's contents: Use cd to change to a new directory: Use wildcards instead of typing out long directory names: Use ../ to move…
Suggested Courses

765 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question