I think you're misinterpreting the output from your program. 

Opening 1 of 4 Thread 1 starts processing file 1
Opening 2 of 4 thread 2 starts processing file 2
Closing 1 of 4 Thread 1 finished processing file 1 and ends
Opening 3 of 4 Thread 3 starts processing file 3;             thread 2
+ is still processing file 2
Closing 3 of 4 thread 3 finishes processing file 3 and ends;  thread 2
+ is still processing file 2
Opening 4 of 4 Thread 4 starts processing file 4;             thread 2
+ is still processing file 2
Closing 2 of 4 Thread 2 finishes processing file 2 and ends.
Closing 4 of 4 Thread 4 finishes processing file 4 and ends.

[download]

That all looks pretty much as might be expected to me. What makes you think something is wrong?

The only problem I see is that you have no way to exit the loop when all files have been processed.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
"I'd rather go naked than blow up my ass"

In reply to Re: wait for threads to end in parallel by BrowserUk
in thread wait for threads to end in parallel by pmarcoen

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.