Function mmal_sys::mmal_buffer_header_pre_release_cb_set

pub unsafe extern "C" fn mmal_buffer_header_pre_release_cb_set(
    header: *mut MMAL_BUFFER_HEADER_T, 
    cb: MMAL_BH_PRE_RELEASE_CB_T, 
    userdata: *mut c_void
)

Set a buffer header pre-release callback. If the callback is NULL, the buffer will be released back into the pool immediately as usual.

@param header buffer header to associate callback with @param cb pre-release callback to invoke @param userdata user-specific data