Actually all three arguments to split [pattern;[, expression, limit]] are optional.

I find that statement misleading. See the 'template' at the top of spilt:

split /PATTERN/,EXPR,LIMIT
split /PATTERN/,EXPR
split /PATTERN/
split

[download]

This implicitly (and rightly) excludes:

split EXPR

Which is exactly what the OP tries to do in the line:

@mails = split ('$line');

This is why the OP's code generates the following error:

Use of uninitialized value $_ in split at XX.pl line YY.

IOW, the 'expression' argument is optional only if the 'pattern' argument is present.

In reply to Re^3: passing arrays by Not_a_Number
in thread passing arrays by ScOut3R

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