UniStrxfrm transforms the string pointed to by ucs2 to values that represent character collating weights and places the resulting string into the array pointed to by ucs1. The transformation is such that, if UniStrcmp is applied to two transformed strings, it returns a value greater than, equal to, or less than 0, corresponding to the result of UniStrcoll applied to the same two original strings. No more than n elements are placed into the resulting array pointed to by ucs1, including the ending null code element. If n is zero, ucs1 is permitted to be a null pointer. If copying takes place between objects that overlap, the results are unpredictable.

UniStrxfrm is controlled by the LC_COLLATE category of the locale as indicated by the locale object handle argument, locale_object.