Then of course you can't use the usual file operators to read your data (but you shouldn't be doing that with a binary file anyway, even on *nix -- hopefully someone with more *nix experience can point out the pitfalls there).

You can use the usual file operators. There is nothing wrong with using them to read binary data. In fact, it can be quite handy as long as you understand what you are doing.

Usually, you'll want to change $/, the input record separator, before you do so. By default, $/ is a newline which is unlikely to be a meaningful delimiter in your binary data. A null, "\0", is often used to delimit variable length records though. If you have fixed length records or even if you just want to read chunks of a specific length in, you can do that by setting $/ to a reference. For example, 

$/ = \16384;

[download]
would result in 16Kb block reads. Another useful value to set $/ to for binary data (as well as for text) is undef. Setting it to undef results in the whole file being slurped in a single read.

-sauoq
"My two cents aren't worth a dime.";

In reply to Re: Re: perl in DOS woes by sauoq
in thread perl in DOS woes by manzico

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.