Question

The following code is returning an expression unused warning on the assignment operation in the block. The code isn’t very practical, but there is a lot more code in the excluded section and that code has to run on a particular queue.

__block NSNumber *pageId=nil;
dispatch_sync(_myDispatchQueue, ^{
    int val;
    //... code generates an int and puts it in val
    pageId = [NSNumber numberWithInt:val];
}];
//pageId used below

How do I get rid of this error?

Answer 1

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-value"
 pageId = [NSNumber numberWithInt:val];
#pragma clang diagnostic pop