Function mmal_sys::mmal_pool_pre_release_callback_set

pub unsafe extern "C" fn mmal_pool_pre_release_callback_set(
    pool: *mut MMAL_POOL_T, 
    cb: MMAL_BH_PRE_RELEASE_CB_T, 
    userdata: *mut c_void
)

Set a pre-release callback for all buffer headers in the pool. Each time a buffer header is about to be released to the pool, the callback will be triggered.

@param pool Pointer to the pool @param cb Pre-release callback function @param userdata User-specific data passed back with each callback