ruby_enc_find_extname  230 ext/pathname/pathname.c     ext = ruby_enc_find_extname(p, &extlen, rb_enc_get(str));
ruby_enc_find_extname 4263 file.c             e = ruby_enc_find_extname(name, &len, rb_enc_get(fname));
ruby_enc_find_extname  282 include/ruby/encoding.h const char *ruby_enc_find_extname(const char *name, long *len, rb_encoding *enc);