[perl #60204] Unhelpful error message from unpack

[perl #60204] Unhelpful error message from unpack

Nigel Sandever said:
> The error message produced by the following snippets is very unhelpful:
>
> c:\>perl -wle"print unpack 'v/a*', qq[a]"
> '/' must follow a numeric type in unpack at -e line 1.
>
> c:\>perl -wle"print unpack 'v/a*', ''"
> '/' must follow a numeric type in unpack at -e line 1.
>
> c:\>perl -wle"print unpack 'v/a*', ' '"
> '/' must follow a numeric type in unpack at -e line 1.

The "problem" is that the data string is too short. But
unpack doesn't generate a warning (or croak) in this case
for simple patterns:

mhx@r2d2 $ perl -MData::Dumper -we'print Dumper([unpack "n", "a"])'
$VAR1 = [];

So, I'd say your code should just behave in exactly the
same way. No warning, no return values.