In one of my modules I have a statement like this:

$MyApp::once{x} ||= 1;
[download]

Perl warns Name "MyApp::once" used only once: possibly typo. While it is true that this happened to be the only usage of %Pck::v in my program at the time, I wonder what is the best way to suppress this warning. Clearly I can't use use vars nor our here. Sure I can suppress the warnings with no warnings in the surrounding block. Any other suggestion?

OK, maybe we have a XY problem here, so this is how I stumbled into this problem (maybe you have a better suggestion, but I still would be interested in an answer to my original question as well): I have some functions, which gets executed often, but are supposed to log some information only during the first time they are executed:

sub f {
  ...
  log('some information'); # but should be called only the first time.
  ...
}
[download]

In languages such as C++, I would use a local static for this purpose:

  static LogRetType const once=log('some information');
[download]

We don't have local statics in Perl, so one possibility would be to use a 'my' variable on file scope:

my $once1=0;
sub f {
  ...
  $once1 ||= (log('some information'),1);
  ...
}
[download]

But I neither like the fact that the definition of $once1 is not logically close to its (only) usage, but also that I need to invent a new variable every time I do this in my package. So I thought that I would instead have a single variable of this kind for my whole application, but use a hash for this purpose, and the file name and line number as a key:

sub f {
   ...
   $MyApp{+__FILE__.' '.__LINE__} ||= (log('some information'),1);
   ...
}
[download]

This works, as long as I have two or more lines of this type in my package; but if there is only one occurence, I get the aforementioned warning.

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