- (IBAction)action:(id)sender {
int i=10000;
NSString * data;
dispatch_queue_t queue = dispatch_queue_create("com.wang.queue", NULL);
while(i>0)
{
    @autoreleasepool {
        data = [[NSString alloc]initWithFormat:@"%i",i];
        NSString * str = data;
        dispatch_async(queue, ^{{
            [self print:str];
        }});
        i--;
    }
}

}

-(void) print:(NSString*)str
{
    NSLog(@"%@",str);
    str = nil;
}