Availability:C-language interface function
REP_ISO_LATIN_1, REP_UTF8 or REP_MB. 
If
len is (size_t)-1, it is computed from s 
using strlen().
REP_ISO_LATIN_1, REP_UTF8 or REP_MB. 
If
len is (size_t)-1, it is computed from s 
using strlen().