ONIGENC_MBCLEN_CHARFOUND_P  117 include/ruby/encoding.h #define MBCLEN_CHARFOUND_P(ret)     ONIGENC_MBCLEN_CHARFOUND_P(ret)
ONIGENC_MBCLEN_CHARFOUND_P   57 regenc.c         if (ONIGENC_MBCLEN_CHARFOUND_P(ret))