in reply to Re^2: Warning in objImageMagick
in thread Warning in objImageMagick

Hi Anonymous,

It looks like you missed the warn statement in front of "$obj_temp" if "$obj_temp", and your precedence on the .0+$obj_temp in the last warn isn't quite right. Also, you'll probably want to further inspect $obj_temp only if it actually was an error, something like:

my $obj_temp = $objImageMagick->Read("foo.jpg","bar.jpg");
if ("$obj_temp") {
    $obj_temp =~ /(\d+)/;
    warn "Error Number $1, number of images read: ".(0+$obj_temp);
    # handle the error further, like maybe "die"
}

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When I run this with the file foo.jpg existing and the file bar.jpg not existing, I get the output:

Error Number 435, number of images read: 1 at ....

[download]

Hope this helps,
-- Hauke D

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Re^4: Warning in objImageMagick
by Anonymous Monk on Apr 02, 2016 at 17:45 UTC
    Did this way and it oppressed the warnings:
    my $obj_temp = "";
   
   $obj_temp = $objImageMagick->Read("dir/$filename");
  
   warn "$obj_temp" if $obj_temp =~ /(\d+)/; # print the error message
   
   warn "Error Number: ".$1." Number of images read: ".0+$obj_temp if 
+$obj_temp =~ /(\d+)/;

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[reply]
[d/l]

      Hi Anonymous,

      Actually there's still a bug in there, you'll still get the same "Argument ... isn't numeric in addition" warning when Read fails. warn "message... ".0+$obj_temp is interpreted by Perl as warn "message... 0" + $obj_temp; (i.e. the concatenation happens first) instead of what you want, warn "message... ".(0+$obj_temp). Try it yourself: perl -MO=Deparse,-p -e 'warn "message... ".0+$obj_temp'

      The reason is the operators + and . have the same precedence but are left associative (compare the output of the aforementioned Deparse with this: perl -MO=Deparse,-p -e 'warn 0+$obj_temp."message... "'). You should use parentheses to set the precedence and for clarity.

      Regards,
      -- Hauke D

[reply]
[d/l]
[select]
        So this line should be like this:
        warn "Error Number: ".$1." Number of images read: ".(0+$obj_temp) if $
+obj_temp =~ /(\d+)/;

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[reply]
[d/l]

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