Re: When do filehandles close?

A filehandle will bet closed when:

It is formally closed with close
When it goes out of scope which occurs:
1. If it is localised to a block and you exit said block, provided no closure of course
2. When the program exits everything goes out of scope.

Examples, no or die $! for clarity not form.

open F, $file;
close F;
# F is closed

{
    open my $fh, $file;
}
# $fh is closed

open F, $file;
exit 0;
# program is gone and F is closed

# closure
{
    my $fh;
    sub append {
        unless ( $fh ) { open $fh, $file }
    }
}
# closure means $fh is not destroyed, $fh remains open until program e
+xit
[download]

cheers

tachyon

Comment on Re: When do filehandles close? Download Code

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Re^2: When do filehandles close? by pg (Canon) on Jul 23, 2004 at 00:04 UTC
Missed one little thing;-) as the OP already pointed out, reopen implicitly close a file handler. However in this case $. (current line number for the last filehandle accessed) is not reset. I would prefer explicit close all the time simply because of this. Update Just add a piece of code for demon (name this script a.pl): `use strict; use warnings; open(SCRIPT, "<", "a.pl"); <SCRIPT>; <SCRIPT>; print $., "\n"; #close(SCRIPT); open(SCRIPT, "<", "a.pl"); <SCRIPT>; print $., "\n";` [download] Try to comment or uncomment that close. If it is commented, print out: `2 3` [download] If it is not commented: `2 1` [download]	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^2: When do filehandles close?
by pg (Canon) on Jul 23, 2004 at 00:04 UTC

Missed one little thing;-) as the OP already pointed out, reopen implicitly close a file handler.

However in this case $. (current line number for the last filehandle accessed) is not reset. I would prefer explicit close all the time simply because of this.

Update

Just add a piece of code for demon (name this script a.pl):

use strict;
use warnings;

open(SCRIPT, "<", "a.pl");
<SCRIPT>;
<SCRIPT>;
print $., "\n";
#close(SCRIPT);
open(SCRIPT, "<", "a.pl");
<SCRIPT>;
print $., "\n";
[download]

Try to comment or uncomment that close. If it is commented, print out:

2
3
[download]

If it is not commented:

2
1
[download]

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom