The problem is that main::FO1 looks like a file handle. Workarounds: 
print main::FO1();
print "".main::FO1;
print STDOUT main::FO1;

[download]

That said, it makes no sense for a module to rely on the calling script to have a certain function defined.

In reply to Re: Accessing main::Constant by ikegami
in thread Accessing main::Constant by nagalenoj

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