Serial Port Connection

fbasma · 02-23-2010, 07:24 PM

hello ,

i'm trying to access one of the serial ports, i've used the code posted in the the following website: http://www.tldp.org/HOWTO/Serial-Pro...OWTO/x115.html

The connection works , i start reading from the port, however when i terminate the program ( Control C), i try to reactivate it again , but nothing happens ( it seems like going in an infinite loop). the only way to fix it is to remove the cable and then plug it back again.

any ideas why this is going on ?

I'm using slackware 2.6.31

Thanks in advance.

Elv13 · 02-23-2010, 09:23 PM

When you open a file, close it. A device is a file too in Linux. Be sure when Ctrl+C is pressed to free your ressources, and not just terminate the program. You have to listen to signals (SIGQUIT, SIGKILL) to do that.

fbasma · 02-24-2010, 11:15 AM

Thanks alot,

if your referring to the process itself, i've already checked its execution, however, i thought once the process itself is killed , the resources are freed as well. If that is not the case , how can i check the resources used by the process itself?

however what i did is tried the same program under fedora , it worked fine, i couldn't even replicate the problem.
i was wondering whether the problem might be with either the kernel version or with slackware.

Thanks again.

Elv13 · 02-24-2010, 07:30 PM

the fuser and lsof command will help. But -always- close your resources manually, killing wont free all. A serial connection is kind of stupid, it does not detect the end until you call it. It may be the problem.