From: Bedo Sandor <bsanyi@...>
Date: 2003-07-15T18:17:17+09:00
Subject: file locking




  Hi All,

There are 3 different file locking mechanisms in C:

	flock
	lockf
	fcntl

I want to write a Ruby script, which shares files with
a C program using all of these lockings.

As I can see objects with the type File have an flock
method.  This is the only one I can use.  There is an
fcntl method, but I don't know how to use it.  What
kind of parameters can I pass to fcntl?  I want to
implement this code in Ruby for fcntl:

	def lock_fcntl(fd)
	
		# struct flock f_lock;

		# memset(&f_lock, '\0', sizeof(f_lock));
		# f_lock.l_type   = F_WRLCK;
		# f_lock.l_whence = SEEK_SET;
		# f_lock.l_start  = 0;
		# f_lock.l_len    = 0;
		# fcntl(fd, F_SETLKW, &f_lock);
	
	end

and I need a lockf-type method too:

	def lock_lockf(fd)
		# ???
	end

Could you show me how to use fcntl, and how to
access lockf from Ruby?

-- 
bSanyI