Converts all Unicode characters in the string that have a case to lowercase. The exact manner that this is done depends on the current locale, and may result in the number of characters in the string changing.
a UTF-8 encoded string
length of str, in bytes, or -1 if str is nul-terminated.
a newly allocated string, with all characters converted to lowercase.
Converts all Unicode characters in the string that have a case to lowercase. The exact manner that this is done depends on the current locale, and may result in the number of characters in the string changing.