sleeping in a thread

Hello, I will preface this with the fact I am a newbie.

I am running angstrom 3.2.0 on a AM335x kit. I have created an application with a thread that checks to see if a USB drive has been attached.

In the thread where I periodically check to see if the Usb Host has be mounted or not , I sleep.

I have a couple of questions.

1) should i use sleep(), nanosleep(), or pthread_yield()?

2) the other dumb question is i was expecting the application thread to be running in the background allowing me to continue using the command line. this is not the case, the command line is locked up while the application thread is running. is there anyway around this (i.e. i can run my application in the background and still have access to the command line?)

thanks for your help

1) not an expert, but i'd say sleep.

2) put an "&" (without quotes) at the end of the command, then press enter.

You should NOT use sleep.

You can try:
http://www.qnx.com/developers/docs/6...epon_wait.html
http://somethingswhichidintknow.blog...n-pthread.html

What I do when using threads is never assume a function is thread safe. Try as much as possible to use pthreads functions and to make sure other functions are thread safe.

Also, I would make sure that I really need a thread before starting one.

Thanks a lot this helps.

Again a dumb question. You mention to make sure that I really need a thread before starting one.

Like I mentioned, my application periodically checks to see if a USB drive is there and process accordingly. It only does this. So I only have one thread.

If I did not create a thread and just ran my code in a while loop in main. Does this just create a unique process? Are there any detrimental affects to the rest of my linux system running from doing this?

Should I use fork in the main application instead. That way I have access to the command line while mp application (process) is running?

Thanks again.

angstrom 3.2.0 on a AM335x kit

what is this exactly?

are you talking about shell scripting or programming, what sort of linux (distro) are you running there?

Originally Posted by brentw Thanks a lot this helps. Again a dumb question. You mention to make sure that I really need a thread before starting one. Like I mentioned, my application periodically checks to see if a USB drive is there and process accordingly. It only does this. So I only have one thread. If I did not create a thread and just ran my code in a while loop in main. Does this just create a unique process? Are there any detrimental affects to the rest of my linux system running from doing this? Should I use fork in the main application instead. That way I have access to the command line while mp application (process) is running? Thanks again.

I don't think you need a thread for this. Just run it in the main loop. As long as you let the system sleep using whatever sleep function you want, there should be no detrimental effects.

You can send a program to the background using '&' as mentioned above. It will output its pid in case you need to kill it.

Maybe use daemon() (man 3 daemon)

Thanks for the information!