You could use 

    sub foo { ... }

    *foo->(...);

[download]
to receive compile-time warnings, assuming you don't use any other global datatype called foo (and doesn't try to call the same undefined subroutine twice).

Update: boldened "warnings" and added parenthesis.

ihb

Read argumentation in its context!

In reply to Re^2: Detect undefined subroutines by ihb
in thread Detect undefined subroutines by Sprad

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