I just started working in Perl the other day and it's been going pretty well but today I hit a hitch I can't seem to overcome. I was creating a do...while loop (this also occurs in a simple while loop) with an embedded sleep statement and it was giving me some strange behavior. Finally, I narrowed down to this: 
do {
    sleep(5);
    printf "Hello...\n";
} while(1);

[download]
it outputs "Hello..." at 5 second intervals. where as this: 
do {
    sleep(5);
    print "Hello...";
} while(1);

[download]
displays nothing and just hangs until I hit C-c. Why will the first one display "Hello..." while the second without "\n" not? It must have to do with sleep because if I remove it both will be displayed ad infinitum.
Thanks much for your help in advance.
-K

In reply to Troubles with do...while loop and sleep by imlepid

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.