Consider this simple perl program: 

#!/usr/bin/perl -w
sub handle_error
{
    if (open LOG, ">/dev/null") {
        carpout(LOG);
    }
}
print "hello world.\n";

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The intent is to display a very small program to illustrate a problem with a much larger one (whose purpose and design is irrelevant at this point). The problem is, running the program yields a warning from perl: 

Name "main::LOG" used only once: possible typo at bar.pl line 4.

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The context of LOG's use seems clear that it's a parameter to another function, so it's not "used once." ...at least, not in a way that should warn the user. Now, if perl is going to follow that function to see what its doing with that parameter and seeing that nothing is done, fine. But it isn't, so isn't the warning unnecessary? (If you introduce an actual compile-time error, the warning goes away entirely.)

Dan Heller
http://www.danheller.com

In reply to unnecessary warning message? by argv

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