This function is similar to strcasecmp(), with the
difference that you can specify the (upper limit of the) number of
characters from each string to be used in the comparison. Parameters :
str1 - The first string.
str2 - The second string.
len - The length of strings to be used in the comparison.
Syntax
int strncasecmp
( string $str1
, string $str2
, int $len
)