Function queue_read 

pub unsafe extern "C" fn queue_read(
    s: *mut queue_state_t,
    buf: *mut u8,
    len: c_int,
) -> c_int

Read bytes from a queue. \brief Read bytes from a queue. \param s The queue context. \param buf The buffer into which the bytes will be read. \param len The length of the buffer. \return the number of bytes returned.