File locking

ruby-talk
1

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

2

Saluton!

  • Bedo Sandor; 2003-07-15, 12:46 UTC:

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.

Maybe ‘filelock’ is what you are looking for (at least it works fine
when sharing mbox files with mutt).

Gis,

Josef ‘Jupp’ Schugt

···

–
N’attribuez jamais à la malice ce que l’incompétence explique !
– Napoléon

3

have you checked it ‘http://raa.ruby-lang.org/list.rhtml?name=filelock’
out

-r.

Bedo Sandor wrote:

···

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?

–
General Electric - CIAT
Advanced Engineering Center

Rodrigo Bermejo
Information Technologies.
Dial-comm : *879-0644
Phone :(+52) 442-196-0644
mailto:rodrigo.bermejo@ps.ge.com