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From: PerlFAQ Server on 6 Mar 2010 00:00
This is an excerpt from the latest version perlfaq5.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .

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5.34: How do I close a file descriptor by number?

If, for some reason, you have a file descriptor instead of a filehandle
(perhaps you used "POSIX::open"), you can use the "close()" function
from the "POSIX" module:

use POSIX ();

POSIX::close( $fd );

This should rarely be necessary, as the Perl "close()" function is to be
used for things that Perl opened itself, even if it was a dup of a
numeric descriptor as with "MHCONTEXT" above. But if you really have to,
you may be able to do this:

require 'sys/syscall.ph';
$rc = syscall(&SYS_close, $fd + 0); # must force numeric
die "can't sysclose $fd: $!" unless $rc == -1;

Or, just use the fdopen(3S) feature of "open()":

{
open my( $fh ), "<&=$fd" or die "Cannot reopen fd=$fd: $!";
close $fh;
}



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The perlfaq-workers, a group of volunteers, maintain the perlfaq. They
are not necessarily experts in every domain where Perl might show up,
so please include as much information as possible and relevant in any
corrections. The perlfaq-workers also don't have access to every
operating system or platform, so please include relevant details for
corrections to examples that do not work on particular platforms.
Working code is greatly appreciated.

If you'd like to help maintain the perlfaq, see the details in
perlfaq.pod.
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