Re: passing file handle to functions

Why not use a variable for your filehandle?

Example from the perlfunc docs


# process argument list of files along with any includes

 foreach $file (@ARGV) {
    process($file, 'fh00');
}

sub process {
    my($filename, $input) = @_;
    $input++;               # this is a string increment
    unless (open($input, $filename)) {
      print STDERR "Can't open $filename: $!\n";
      return;
    }

    local $_;
    while (<$input>) {              # note use of indirection
       if (/^#include "(.*)"/) {
           process($1, $input);
           next;
       }
       #...                # whatever
    }
}

See perliol for detailed info on PerlIO.
[download]

Hope it help

UnderMine

Comment on Re: passing file handle to functions Download Code

Replies are listed 'Best First'.
Re^2: passing file handle to functions by davorg (Chancellor) on May 18, 2006 at 07:54 UTC
`foreach $file (@ARGV) { process($file, 'fh00'); } sub process { my($filename, $input) = @_; $input++; # this is a string increment unless (open($input, $filename)) { print STDERR "Can't open $filename: $!\n"; return; } local $_; while (<$input>) { # note use of indirection if (/^#include "(.)"/) { process($1, $input); next; } #... # whatever } }` [download] Did you try that under "use strict"? Can't use string ("fh01") as a symbol ref while "strict refs" in use* From perldoc open: If FILEHANDLE is an undefined scalar variable (or array or hash element) the variable is assigned a reference to a new anonymous filehandle, otherwise if FILEHANDLE is an expression, its value is used as the name of the real filehandle wanted. (This is considered a symbolic reference, so use strict 'refs' should not be in effect.) So what you're trying only works with "use strict" if the variable that you use for the filehandle contains an undefined value. -- <http://dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re^3: passing file handle to functions by UnderMine (Friar) on May 18, 2006 at 11:32 UTC
True. I was quoting directly from perldoc perlfunc examples for open. Which seams different from the perldoc open. UnderMine	[reply]
Re^4: passing file handle to functions by japhy (Canon) on May 18, 2006 at 11:38 UTC
Wow. That example should probably just go away from the docs. It's not strict-safe and it doesn't even make sense: the filehandle variable is 'fh01' every time. Jeff `japhy` Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and `perl` hacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart	[reply]


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