ONIGENC_MBCLEN_CHARFOUND_LEN  118 include/ruby/encoding.h #define MBCLEN_CHARFOUND_LEN(ret)     ONIGENC_MBCLEN_CHARFOUND_LEN(ret)
ONIGENC_MBCLEN_CHARFOUND_LEN   58 regenc.c           return ONIGENC_MBCLEN_CHARFOUND_LEN(ret);