Hi all,
          I am trying to stop running multiple instances of my code.
i have done some thing like this,

        if ((tempFD = open(tempFileName, O_RDWR | O_CREAT | O_EXCL)) <
0)
           return (1);

      if ((tempFD1 = open(tempFileName1, O_RDWR | O_CREAT | O_EXCL)) <
0)
           return (1);

Thing is it works for limited instances but when it exceeds it
breaks.Can some body
explain how to do it in C programming.

Thanks
Prasanna

"Mavinkuli" <boss_bhat@yahoo.co.in> wrote:
# Hi all,
#           I am trying to stop running multiple instances of my code.
# i have done some thing like this,
# 
#         if ((tempFD = open(tempFileName, O_RDWR | O_CREAT | O_EXCL)) <
# 0)
#            return (1);
# 
#       if ((tempFD1 = open(tempFileName1, O_RDWR | O_CREAT | O_EXCL)) <
# 0)
#            return (1);

I do something like
	lockfd = open(lockpath,O_RDWR|O_CREAT);
	if (flock(lockfd,LOCK_EX|LOCK_NB)<0) {
		some other process has the lock
		exit(0);
	}else {
		this process has seized the lock
		do not unlock or close lockfd
		on process exit the lock will be released by the kernel
		...
	}


--
SM Ryan http://www.rawbw.com/~wyrmwif/
TEMPORARILY CLOSED
BE OPENED AFTER FIRST PERIOD

I have SunOS brahma 5.8 box
But when I compile this fix it says LOCK_EX and LOCK_NB are undefined.
I have even included the file sys/file.h but still it fails to compile

Mavinkuli wrote:
> I have SunOS brahma 5.8 box
> But when I compile this fix it says LOCK_EX and LOCK_NB are undefined.
> I have even included the file sys/file.h but still it fails to compile
Read the manpage for flock, maybe you need som other headers.
See the lockf function too.