First time posting on this board hopefully someone will able to help me.
I am looking for some examples of c programs which use a signal to notify the program to begin a certain action instead of having it continually loop to check to see if condition is attained(busy wait). Any tutorials or examples
will be appreciated.
This is how I think it should be done but still feels like a busy wait
if(x == 5) // where x is the condition under which I want
// program to execute the action.
I am looking for some examples of c programs which use a signal to notify the program to begin a certain action instead of having it continually loop to check to see if condition is attained
I suggest a program based around select and have a pipe pair dedicated to supporting signals. The write end is written by the signal handle (write a single byte containing the number of the signal) and have the select include the read end of the pipe in the read fd_set.
Then when a signal occurs a single byte is written to the pipe, this wakes up the select, the code in the select loop then reads the pipe and knows which signal occurred and can then handle it in a more graceful manner.
I am facing a strange issue,
when i call a script from my while loop in background it doesnt go in background, despite the wait i put below the whil loop it goes forward even before the process put in background is completed.
cat abc.txt | while read -u4 line
#if line contains #... (2 Replies)
We have a filesystem mystery on our hands. Given:
2 machines, A and Aa.
Machine Aa is the problem machine.
Machine A is running Ubuntu, kernel 126.96.36.199 #1 SMP Wed Feb 20 08:46:16 CST 2008 x86_64 GNU/Linux. Machine Aa is running RHEL5.3, kernel 2.6.18-128.el5 #1 SMP Wed Dec 17 11:41:38... (2 Replies)
Did not use 'wait' yet.
How I understand by now the wait works only for child processes, started background.
Is there any other way to watch completion of any, not related process (at least, a process, owned by the same user?)
I need to start a background process, witch will be waiting... (2 Replies)
I need to execute a shell script to do the following:
cat a file
run two back ground processes using the first two values from the file
wait till those background processes finish
run two more background processes using the next two values from the file
wait till those background... (1 Reply)
one problem which seems simple but i've faced many times is when i've used cd & want to eject, however i'm not in /dev/cdrom/... in any of my Xterms but it gives the message that the the CD drive is busy.
the only thing i could do is /etc/init.d/volmgt stop & eject the CD manually but it doesn't... (6 Replies)