A race condition could happen, if something changes to the file between the time I check the existence, and the time I read the file. However, the file is pretty static:

With the network involved, it doesn't have to be the file that changed. Any temporary resource state in the fabric between you and the actual file could -- breifly -- manifest itself as in an inability to open the file.

I'd suggest cutting out the possibility of a race by just opening the file. And if the open fails, retry some number of times before logging an error:


for my $try ( 1 .. RETRIES ) {
  if(open(my $rule_fh,'<',$rule_file)) {
    last;
  }
  if( $try == RETRIES ) {
    die "Can not read file $rule_file : $! / $^E";
  }
}

[download]
With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
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.

RIP Neil Armstrong

In reply to Re^5: Spurious "Invalid Argument" on file open by BrowserUk
in thread Spurious "Invalid Argument" on file open by rovf

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.