Looks like they have the same problem. They're using LC_CTYPE to hint mbrtowc(). In fact, if you web search "mbrtowc slow" you'll get a bunch of hits about "W

Looks like they have the same problem. They're using LC_CTYPE to hint mbrtowc(). In fact, if you web search "mbrtowc slow" you'll get a bunch of hits about "Why is wc so slow"!! :-)