PHP字符串比较不适用于图像元数据

Question

I am extracting image metadata using php. The logic of my below code is that if the user uploads the default file with metadata(UserComment)=ASCIIsd11, he/she will get an error.

<?php
$exif_s = exif_read_data('e42889ed00.jpg');
$phtchk = $exif_s["UserComment"];
print $phtchk;
print strcmp($phtchk, "ASCIIsd11");
if(strcmp($phtchk, "ASCIIsd11") == 0){ echo "You have not uploaded your own photo"; exit;} 
else
{
echo"You have uploaded it.";
}
?>

print $phtchk; returns ASCIIsd11

print strcmp($phtchk, "ASCIIsd11"); returns -1

and the last echo statement "You have uploaded it" is printed. Actually I am expecting strcmp() to return 0 . Kindly help.

Answer 1

Do var_dump(phtchk); instead of print $phtchk; Perhaps you don't see some extra-chars (eg: \\n ).

If it concerns the collation, you should see: UTF-8 characters not displaying properly from JPEG IPTC data in PHP