in reply to file modified

For me, it doesn't look right. Note that -M subtracts $^T (the invocation time of perl) from the mtime, so if you don't change the file, the result of -M won't increase in such a loop.

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Re^2: file modified
by Anonymous Monk on Jan 07, 2005 at 16:36 UTC
    Yeah it does not work properly. Basically if a file has not been modified for more than an hour, I go and check the contents of the file (comparison etc.), else I wait till the last modified time becomes more than 1 hr

    What is really happening is that my code goes into the while loop and does not come out...even after an hour. What do you advice? Thanks.

[reply]
      What is really happening is that my code goes into the while loop and does not come out...even after an hour. What do you advice? Thanks.
      (Smacking hand on forehead...)

      It would have helped for you to say that! OK, I see what's happening now. -M is not going to change in that loop for a file that's being "left alone", because the value is measured relative to the start of the program (as captured in $^T)!

      Maybe what you want is more like this: 

      {
  die unless my @stat = stat $the_file;
  my $seconds_until_one_hour_old = 3600 - (time - $stat[9]);
  last if $seconds_until_one_hour_old <= 0; # already old enough
  sleep $seconds_until_one_hour_old; # not yet
  redo; # and test again
}

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      -- Randal L. Schwartz, Perl hacker
      Be sure to read my standard disclaimer if this is a reply.

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