Created a hashed substring
char *SLang_create_nslstring (char *s, unsigned int n)
SLang_create_nslstring is like SLang_create_slstring
except that only the first n characters of s are used to
perform the string. Upon error, it returns NULL, otherwise it
returns the hashed substring. Such a string must be freed by the
function SLang_free_slstring.
Do not use free or SLfree to free the string returned by
SLang_create_slstring or SLang_create_nslstring. Also
it is important that no attempt is made to modify the hashed string
returned by either of these functions. If one needs to modify a
string, the functions SLmake_string or SLmake_nstring
should be used instead.
SLang_free_slstring, SLang_create_slstring, SLmake_nstring