unable to resolve warning "Use of uninitialized value in ..."

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

Hello monks,

can't get my way out the following :

  $class = "winmgmts:{impersonationLevel=impersonate}\\\\$key\\Root\\c
+imv2";
  $process_info = Win32::OLE->GetObject( $class ) || warn "\n shit";
  
  my $cnt = 0;
  foreach my $process ( sort { $a->{Name} cmp $b->{Name}} 
    in( $process_info->InstancesOf( "Win32_Process" ))) {

    print LOG $process -> {Name} . "\n";
    print LOG $process -> {ProcessID} . "\n";
    print LOG $process -> {ExecutablePath} . "\n\n";
  }
[download]

The thing is

$process -> {ExecutablePath}
[download]

can be empty (that causes the warning if I'm right). I can't test

if ( "" ne $process->{ExecutablePath} ) {
  ...  
}
[download]

cos warning again!

Hope someone can point out what am doing wrong.
Thanks

Have a nice day.

Comment on unable to resolve warning "Use of uninitialized value in ..." Select or Download Code

Replies are listed 'Best First'.
Re: unable to resolve warning "Use of uninitialized value in ..." by Corion (Patriarch) on Oct 24, 2005 at 13:56 UTC
The way to check for an undefined value in Perl is `if (defined $value) { ... };` [download] (see `perldoc -f defined` for more information). You could also turn off the warning, but usually, turning off a warning is a bad practice because you're likely to forget to turn it on again immediately afterwards. `{ no warnings 'uninitialized'; print LOG $process->{ExecutablePath}, "\n"; };` [download]	[reply] [d/l] [select]
Re: unable to resolve warning "Use of uninitialized value in ..." by jhourcle (Prior) on Oct 24, 2005 at 13:58 UTC
Blank is different from uninitialized ... try changing the test to: `if ( not defined($process->{ExecutablePath} )) { ... }` [download]	[reply] [d/l]
Re: unable to resolve warning "Use of uninitialized value in ..." by jesuashok (Curate) on Oct 24, 2005 at 14:25 UTC
Hi .. if ( $process -> {ExecutablePath} ) { ...... Code Stuff .... } The above will become true ony if it contains any values. It becomes false for "",'' and undef. "Keep pouring your ideas"	[reply]
Re^2: unable to resolve warning "Use of uninitialized value in ..." by lepetitalbert (Abbot) on Oct 24, 2005 at 14:45 UTC
Hi again, problem solved : `if ( defined $process -> {ExecutablePath} ) { print LOG $process -> {ExecutablePath} . "\n\n"; }` [download] Thanks Have a nice day.	[reply] [d/l]