I would code it like this:

#!/usr/bin/perl -w

use strict;
use Fcntl ':flock';

sub add {
  open FH, ">>$file" or die "Cant open config file $!\n";
  flock(FH,LOCK_EX);
  print FH "zone \"$formdata{domain}\" in \{\n\ttype slave\;\n\tfile\"
+$client\/db.$formdata{domain}\"\;\n\tallow-query \{ any\; \}\; \}\;\n
+\n";
  close FH;
}
[download]

I see very little advantage in 1 line subs - the lock sub is three lines where 1 will do. If you wanted to make a more useful lock sub that included a timeout/retry feature you would need to pass the file handle to the sub. May as well pass the lock type too:

#!/usr/bin/perl -w

use strict;
use Fcntl ':flock';

sub add {
  open FH, ">>$file" or die "Cant open config file $!\n";
  lock_file(*FH, LOCK_EX);
  print FH "zone \"$formdata{domain}\" in \{\n\ttype slave\;\n\tfile\"
+$client\/db.$formdata{domain}\"\;\n\tallow-query \{ any\; \}\; \}\;\n
+\n";
  close FH;
}

sub lock_file {
   local *FH = shift;
   my $lock = shift;
   my $count = 0;
   my $timeout = 15;
   until (flock FH, $lock) {
       sleep 1;
       die "Can't get lock\n" if ++$count > $timeout;
   }
}
[download]

When you close a file you automatically release any locks so you can just drop the whole concept of unlocking provided you explicitly close.

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.