ios - Editing argument in objective-c blocks -

i want edit uiimage pointer in block it's not allowed.

-(void)downloadimage:(nsurl *)url ofpointer:(uiimage *)imagepointer {     __weak typeof(self) weakself = self;     [sdwebimagemanager.sharedmanager downloadwithurl:url                                              options:0                                             progress:^(nsuinteger receivedsize, long long expectedsize) {}                                            completed:^(uiimage *image, nserror *error, sdimagecachetype cachetype, bool finished) {                                                imagepointer = image;                                                [weakself setneedsdisplay];                                            }]; 

}

i tried pass argument __block it's not allowed too.

-(void)downloadimage:(nsurl *)url ofpointer:(__block uiimage *)imagepointer

is there way edit pointer passed argument?

you need use pointer pointer (uiimage **) image immutable object if change inside block wouldn't have effect desire.

what should use delegation or callback block pass downloaded image out of block instance going use it.