Check after leaving the stack frame.

testStructAndBlocksHeap.m

static BOOL forceRefresh_ = NO;
-(TestAsyncRequestBlock)structBlockBuilder
{
    SDRefreshTraits traits_ = { YES, NO };
    
   
    TestAsyncRequestBlock block_ = ^( JFFSimpleBlock finishBlock_ )
    {
        forceRefresh_ = traits_.forceRefresh;
        finishBlock_();
    };
    block_ = [ block_ copy ];
    
    return block_;
}

-(void)testStructAndBlocks
{
    TestAsyncRequestBlock block_ = [ self structBlockBuilder ];
    
    [ self performAsyncRequestOnMainThreadWithBlock: block_
                                           selector: _cmd ];
    
    GHAssertTrue( forceRefresh_, @"block does not handle C struct properly" );
}