(PHP 5)
substr_compare — Binary safe comparison of two strings from an offset, up to length characters
$main_str
   , string $str
   , int $offset
   [, int $length
   [, bool $case_insensitivity = false
  ]] )
   substr_compare() compares main_str
   from position offset with str
   up to length characters.
  
main_strThe main string being compared.
strThe secondary string being compared.
offsetThe start position for the comparison. If negative, it starts counting from the end of the string.
length
       The length of the comparison. The default value is the largest of the
       length of the str compared to the length of
       main_str less the
       offset.
      
case_insensitivity
       If case_insensitivity is TRUE, comparison is
       case insensitive.
      
   Returns < 0 if main_str from position
   offset is less than str, >
   0 if it is greater than str, and 0 if they are equal.
   If offset is equal to or greater than the length of
   main_str, or the length is
   set and is less than 1 (prior to PHP 5.6),
   substr_compare() prints a warning and returns
   FALSE.
  
| Version | Description | 
|---|---|
| 5.6.0 | lengthmay now be 0. | 
| 5.1.0 | Added the possibility to use a negative offset. | 
Example #1 A substr_compare() example
<?php
echo substr_compare("abcde", "bc", 1, 2); // 0
echo substr_compare("abcde", "de", -2, 2); // 0
echo substr_compare("abcde", "bcg", 1, 2); // 0
echo substr_compare("abcde", "BC", 1, 2, true); // 0
echo substr_compare("abcde", "bc", 1, 3); // 1
echo substr_compare("abcde", "cd", 1, 2); // -1
echo substr_compare("abcde", "abc", 5, 1); // warning
?>