| Subject: | error checking on close() |
Date: Thu, 21 Apr 2005 12:14:06 -0700
From: Eric Wilhelm <ewilhelm@sbcglobal.net>
Subject: error checking on close()
To: Raphael Manfredi <Raphael_Manfredi@pobox.com>
Raphael,
I ran into a problem with the debmirror program which took me quite a
while to track down. The disk was full, but instead of being told
this, I was just getting "use of uninitialized variable" messages from
the chop() statement in _acs_lock().
# Attempt to create lock
if (open(FILE, ">$lockfile")) {
local $\ = undef;
print FILE "$stamp\n";
close FILE;
# here it looks like you are opening the file again
# to ensure that the write worked?
open(FILE, $lockfile); # Check lock
my $l;
chop($l = <FILE>);
$locked = $l eq $stamp;
$l = <FILE>; # Must be EOF
$locked = 0 if defined $l;
close FILE;
last if $locked; # Lock seems to be ours
Maybe you want to do something like this at the first close():
unless(close(FILE)) {
carp("error in writing lockfile $lockfile ($!)");
unlink($lockfile); # maybe not (your call)
return(0);
}
That $! would contain the OS error (in my case "no space left on
device"), which would be very helpful.
Thanks,
Eric