use strict and Win32::API

AcidHawk has asked for the wisdom of the Perl Monks concerning the following question:

Hi, I have the following code to list the running PIDs on a Windows machine. It uses the Win32::API module.

#! /usr/bin/perl

#use strict;
use warnings;

use Win32::API;

#define some constants
my $DWORD_SIZE = 4;
my $PROC_ARRAY_SIZE = 300;
my $MODULE_LIST_SIZE = 300;

#define some Win32 API constants
my $PROCESS_QUERY_INFORMATION = 0x0400;
my $PROCESS_VM_READ = 0x0010;

my $enum_proc    = new Win32::API( 'psapi.dll', 'EnumProcesses', [P,N,
+P], I ) || die "Cannot Enum Processes: $!\n";

#Create a Buffer Array
my $proc_array    = &MakeBuffer($DWORD_SIZE * $PROC_ARRAY_SIZE);
my $proc_num    = &MakeBuffer($DWORD_SIZE);

if (0 != $enum_proc->Call($proc_array, $PROC_ARRAY_SIZE, $proc_num)) {
    $proc_num = unpack ("L", $proc_num) / $DWORD_SIZE;
    print "\$proc_num = $proc_num\n";
    
    my @pid_lst = unpack("L$proc_num", $proc_array);
    foreach my $pid(@pid_lst) {
        print "$pid - Running\n";
    }
}

sub MakeBuffer
{
    my ($buffer_size) = @_;
    return("\x00" x $buffer_size);
}
[download]

You will notice that use strict; is commented out. The reason is that when I uncomment use strict; I get the following error,

Bareword "P" not allowed while "strict subs" in use at C:\dev\Source_P
+erl\MiscTests\pid\roth.pl line 17.
Bareword "N" not allowed while "strict subs" in use at C:\dev\Source_P
+erl\MiscTests\pid\roth.pl line 17.
Bareword "P" not allowed while "strict subs" in use at C:\dev\Source_P
+erl\MiscTests\pid\roth.pl line 17.
Bareword "I" not allowed while "strict subs" in use at C:\dev\Source_P
+erl\MiscTests\pid\roth.pl line 17.
Execution of C:\dev\Source_Perl\MiscTests\pid\roth.pl aborted due to c
+ompilation errors.
[download]

Any ideas how I can still use strict and line 17 together..? I got most of this code from Dave Roths Win32 Perl Scripting book.

-----
Of all the things I've lost in my life, its my mind I miss the most.

Comment on use strict and Win32::API Select or Download Code

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Re: use strict and Win32::API by Corion (Patriarch) on Feb 14, 2003 at 09:38 UTC
Simply put the characters into quotes, as Perl does not want barewords. my $enum_proc = new Win32::API( 'psapi.dll', 'EnumProcesses', [qw[P N +P]], qw[I] ) or die "Cannot Enum Processes: $!\n"; # or my $enum_proc = new Win32::API( 'psapi.dll', 'EnumProcesses', ["P", "N +", "P"], "I" ) or die "Cannot Enum Processes: $!\n"; # or, slightly confusing my $enum_proc = new Win32::API( 'psapi.dll', 'EnumProcesses', [ P => N + => P => ], "I" ) or die "Cannot Enum Processes: $!\n"; # or, slightly perverse use constant P => "P"; use constant N => "N"; use constant I => "I"; my $enum_proc = new Win32::API( 'psapi.dll', 'EnumProcesses', [ P, N, +P ], I ) or die "Cannot Enum Processes: $!\n"; [download] Of course, the last proposal is seen to be as a joke, because real fun will start as soon as you lazily name a file handle `P` and try to read/write with it. `perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ; # The $d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider ($c = $d->accept())->get_request(); $c->send_response( new #in the HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' # web` [download]	[reply] [d/l] [select]
Re: Re: use strict and Win32::API by guha (Priest) on Feb 14, 2003 at 13:12 UTC
Of course, the last proposal is seen to be as a joke, because real fun will start as soon as you lazily name a file handle P and try to read/write with it. Is that a problem ?? Subs (via use constant) and filehandles have different slots in the symboltable AFAIK. Since P, N and I do not need to be interpolated I prefer using ' instead of " with reference to your second alternative. Nice post though++	[reply]
Re: use strict and Win32::API by Enlil (Parson) on Feb 14, 2003 at 09:41 UTC
you should be able to just put quotes around those characters without losing anything (and gaining the ability to use strict). that is: `my $enum_proc = new Win32::API( 'psapi.dll', 'EnumProcesses', [P,N,P +], I ) \|\| die "Cannot Enum Processes: $!\n";` [download] to `my $enum_proc = new Win32::API( 'psapi.dll', 'EnumProcesses', ["P"," +N","P"], "I" ) \|\| die "Cannot Enum Processes: $!\n";` [download] -enlil	[reply] [d/l] [select]
Re: use strict and Win32::API by Cabrion (Friar) on Feb 14, 2003 at 11:32 UTC
The other answers are better in this case. You can also turn strict off in blocks of code using `no strict;` too. Just food for thought.	[reply] [d/l]


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