Unfortunately, having no file *is* a legal situation (and, from the processing logic, equivalent to an empty file)

Then change the logic, and make no file different to an empty file. That is, make it so that the create always creates a file, even if that file is empty. That way, your reader will always wait until there is a file before deciding upon its next action.

Having the absence of a file be logically equivalent to the presence of an empty file creates the situation where the reader takes the crash of the writer to mean the same thing as the writer creating an empty file. And that's just silly. It just creates a false dilemma.

With locking, the reader would have to wait for the writer to unlock the file. This will normally be a short period, but could potentially be forever if the creator crashed whilst holding the lock.

If the reader waits (with timeout) for the appearance of the file you have the same situation.

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.

In reply to Re^3: locking over the network by BrowserUk
in thread locking over the network 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.