This function is similar to strcmp, with the difference that you can specify the (upper limit of the) number of characters from each string to be used in the comparison.
Note that this comparison is case sensitive.
The first string.
The second string.
Number of characters to use in the comparison.
Returns < 0 if string1 is less than string2; > 0 if string1 is greater than string2, and 0 if they are equal.