(PHP 4, PHP 5)
strcmp — Binary safe string comparison
$str1
   , string $str2
   )Note that this comparison is case sensitive.
str1The first string.
str2The second string.
   Returns < 0 if str1 is less than
   str2; > 0 if str1
   is greater than str2, and 0 if they are
   equal.
  
Example #1 strcmp() example
<?php
$var1 = "Hello";
$var2 = "hello";
if (strcmp($var1, $var2) !== 0) {
    echo '$var1 is not equal to $var2 in a case sensitive string comparison';
}
?>