the compiler may complain that there's no return: tests.c: In function 'main': tests.c:954: warning: control reaches end of non-void function spotted by the OpenBSD bulk builds on sparc64 (using gcc 4.2)

without a call to mpg123_scan the length returned by mpg123_length is not necessarly accurate (well, even in that case it's not guaranteed to be exact, i.e. if a file is modified while it's playing.) fixes the length reporting on some mp3 files i had around.