...It didn't do that in perl 5.8

Another difference to be aware of is this: 

my $s = "\x{1234}\x{5678}";   # string with utf8 flag on

print unpack("H*", $s), "\n";

[download]

With 5.8 this prints a hexdump of the internal (UTF-8) representation of the string — e.g. useful when debugging encoding issues

e188b4e599b8

[download]

while with 5.10, you'd get 

3478

[download]

i.e. the low-byte values of the codepoints, with the high-byte part being truncated. With warnings enabled, you also get "Character in 'H' format wrapped in unpack at...".

With use bytes, or when explicitly turning off the utf8 flag (update: as shown below), you get the old behaviour.  And specifically for debugging encoding issues, Devel::Peek is the recommended alternative since 5.10, because of this difference.

In reply to Re^2: Understanding pack and unpack changes for binary data between 5.8 and 5.10 by almut
in thread Understanding pack and unpack changes for binary data between 5.8 and 5.10 by dkg

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.