Function qmap_next 

pub unsafe extern "C" fn qmap_next(
    key: *mut *const c_void,
    value: *mut *const c_void,
    cur_id: u32,
) -> c_int

@brief Fetch next key/value.

@param[out] key Pointer to key. @param[out] value Pointer to value. @param[in] cur_id Cursor handle. @return 1 if valid, 0 if done. See qmap_common for pointer ownership rules.