Because the first parameter passed to open
is the file handle. In the first case, there are 3 file handles: 1,2,3. In
the second case, the same file handle is used for each file, always ‘1’.
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Hugh Loebner
Sent: Friday, July 01, 2005 9:21
AM
To: Perl-Win32-Users Mailing List;
activeperl@listserv.ActiveState.com
Subject: Why is this a problem?
Hello perl gurus,
I spent almost a whole day solving this problem. However, I wonder why
it's a problem.
# ////////////////////////////////////////////////////
use strict;
no strict "refs" ;
# this works fine, produces three files, aa , bb, cc with contents 'xxx aa xxx'
etc
my %fh = ( aa => 1, bb =>2, cc => 3) ; # note
that each instance of $fh{$fhkey} has a different value
foreach my $fhkey ( keys %fh){
open ( $fh{$fhkey}, ">$fhkey" )
;
}
foreach my $fhkey ( keys %fh ){
print { $fh{$fhkey} } "xxx $fhkey xxx \n"
; # note file handle $fh{$fhkey} has to be in a block
} ;
foreach my $fhkey ( keys %fh ){
close $fh{$fhkey} ;
}
#------------------------------------------------------------
# The following program (which is what I started out with) will NOT work
properly: Each element of %fh has a value of 1
# Why doesn't this work properly? - all statements write to one file
#------------------------------------------------------------
my %fh = ( aa => 1, bb =>1, cc => 1)
; # note - only change, each $fh{} has value of 1
foreach my $fhkey ( keys %fh){
open ( $fh{$fhkey}, ">$fhkey" )
;
}
foreach my $fhkey ( keys %fh ){
print { $fh{$fhkey} } "xxx $fhkey xxx \n"
; # note file handle $fh{$fhkey} has to be in a
block
} ;
foreach my $fhkey ( keys %fh ){
close $fh{$fhkey} ;
}
# ////////////////////////////////////////////////////
Hugh Loebner
