Fun Perl question

Robin Barker Robin.Barker at
Tue Mar 4 10:37:56 GMT 2008

> So there's me with this bit of code that's running a bit slow. I run 
> the following command:
>  perl -M:DProf ./
> and then follow it with dproffpp to see the results. I'm then left
> scratching my head to work out why I've got "Unable to open tmon.out" 
> before spotting my silly mistake.
> The fun question is: why did the original command seem to work?


	perl -wM:DProf ./

cryptically says:

	Useless use of a constant in void context.

More recent development versions of perl would give:

	Useless use of a constant (DProf) in void context.

As of perl at 33407, "perl -M:DProf ./" fails with:

	Invalid module name :DProf with -M option: contains single ':'.


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