Function speex_lib_ctl 

pub unsafe extern "C" fn speex_lib_ctl(
    request: c_int,
    ptr: *mut c_void,
) -> c_int

Functions for controlling the behavior of libspeex @param request ioctl-type request (one of the SPEEX_LIB_* macros) @param ptr Data exchanged to-from function @return 0 if no error, -1 if request in unknown, -2 for invalid parameter