Re: libtool's locking is wrong

[Pavel Cahyna]

> >       until $run ln "$0" "$lockfile" 2>/dev/null; do
                     ^^^^^^^^^^^^^^^^^^^
> > The ln command fails if the libtool script itself
> > and the working directory are on different filesystems.
> > 
> 
> Why does "ln" fail when the script is on a different filesystem?

Because it is trying to make a hard-link from the current directory
(where $lockfile resides) to itself (the script, whose name is in $0).
But it is not possible to have cross-filesystem hardlinks. See the
manpage for link system call.

By using "par" (which is IRIX equivalent to linux's strace) I determined
that the script actually tries to make a cross-filesystem hardlink and
fails with an error (EXDEV).

Man page for link says (in its section on errors):

...
EXDEV               The link named by path2 and the file named by path1
                         are on different logical devices (file systems).

I hope I cleared it a bit.

Bye     Pavel