Dear Monks,

If case there is a thread already discussing this issue, my apology and please redirect me and I'll read up.

Anyway, I am writing CGI form which creates a new file in a solaris box. Numbers is the filename. There is a history file which stores the last number used. What can I do to make sure that the filename will not get clobbered? I am using following routine: 

$fn_number = get_latest_filename(); # read the history file
while ( -e $fn_number ) {
                $fn_number++;
                update_fn_number();  # update the history file
}
write_thefile($fn_number);

[download]

I tested with 3 users at the submitting the form at same time (well, I tried to make sure three of us clicking the submit button at the same time) and 1 out of 5 testing the form clobbers.

TY,
songahji

In reply to CGI filename race by songahji

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.