why would sv_2nv convert "aa" to a [...] double

Because you asked it to.

how may I avoid this but still have it work for real numbers.

If you need an NV, "aa" would be an error. There are ways of checking that (looks_like_number), but you say you don't want that.

If you need an SV that contains a number if possible, you already have that. You don't need to do anything. Useless numifying is useless.

If it's not useless, it's because you have code that treats PV 1.2 different than NV 1.2, and that's a bug. Perl has an example of that (bitwise ops), and it has caused many headaches.

In reply to Re^5: Why does sv_2nv on non-number look like an NV by ikegami
in thread Why does sv_2nv on non-number look like an NV by mje

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.