my $x = <$f>;
$! and croak "can't read mydata.txt: $!";

[download]

This is incorrect, since Perl does not guarantee that $! is cleared on a successful read. You'll have to check for errors by checking the return value of readline:

open my $fh, '<', 'mydata.txt' or die $!;
defined( my $data = do { local $/; <$fh> } ) or die $!;
close $fh or die $!;

[download]

But may I ask why you need this level of error checking? Are you reading from some kind of network resource for example? Because if it's just a regular file from a local harddisk, failures on e.g. close are pretty rare.

If you really do need this level of security, then one possible solution is using read and making sure the number of bytes read matches the file size - however, the following makes sense only if this is a plain ASCII or binary file, the file is not too huge, and note that the following has a theoretical race condition if someone else happens to be writing to the file at the same time as you're reading from it:

open my $fh, '<:raw', 'mydata.txt' or die $!;
my $size = -s $fh;
read($fh, my $data, $size) == $size or die $!;
close $fh or die $!;

[download]

In reply to Re: bullet proof SLURP file by haukex
in thread bullet proof SLURP file by leszekdubiel

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.