race-condition

问题 I'm wondering if calling setArguments on a Fragment immediately after its instantiation creates any problems. For example, say we have the following snippet: Fragment myFragment = new CustomFragment(); Bundle args = new Bundle(); args.putBoolean("amIAnArg", true); myFragment.setArguments(args); This code seems to work fine, although it looks like the code should create a race condition since a Fragment's arguments can only be set before the onAttach method is called. Are there any issues with

问题 If I want to rename A to B , but only if B doesn't exist, the naive thing would be checking if B exists (with access("B", F_OK) or something like that), and if it doesn't proceeding with rename . Unfortunately this opens a window during which some other process might decide to create B , and then it gets overwritten - and even worse there's no indication that something like that ever happened. Other file system access functions don't suffer from this - open has O_EXCL (so copying files is

问题 I am writing a hotel booking software using PHP and MySQL. I am pretty much done with it but I ran into a race condition problem. For example there is only one standard room left and when 2 guests both select it it shows available to both of them. I tried fixing it by checking the room again when the guest clicks confirm before payment but that still has issues. I also tried making the room status to pending when whoever clicks the confirm first but I can't figure out how to change it back to

问题 I'm trying to call a script deepScript and process its output within another script shallowScript ; it looks schematically like the following pieces of code: shallowScript.sh #!/bin/zsh exec 1> >( tr "[a-z]" "[A-Z]" ) print "Hello - this is shallowScript" . ./deepScript.sh deepScript.sh #!/bin/zsh print "Hello - this is deepScript" Now, when I run ./shallowScript.sh , the outcome is erratic : either it works as expected (very rarely), or it prints an empty line followed by the two expected

问题 In an effort to practice my rusty Java, I wanted to try a simple multi-threaded shared data example and I came across something that surprised me. Basically we have a shared AtomicInteger counter between three threads that each take turns incrementing and printing the counter. main AtomicInteger counter = new AtomicInteger(0); CounterThread ct1 = new CounterThread(counter, "A"); CounterThread ct2 = new CounterThread(counter, "B"); CounterThread ct3 = new CounterThread(counter, "C"); ct1.start

问题 I have a use case where I need to cancel an Ajax call and do something else in an epic. There's an example in the redux-observable doc which fits my need exactly. However, when I try to test the racing condition in my epic, the "cancelation" doesn't seem to work. The example code is like: import { ajax } from 'rxjs/ajax'; const fetchUserEpic = action$ => action$.pipe( ofType(FETCH_USER), mergeMap(action => race( ajax.getJSON(`/api/users/${action.payload}`).pipe( map(response =>

问题 Buckle in, this may be a longer ride than expected... Note: all listeners are delegated to the 'body' and all triggered events are on the 'body' as well. Intended On-Page-Load Flow Create selector with id #selectorA Register listener for #selectA value changed (listener1) that triggers ("aChanged") If condition X, register listener for aChanged that reloads the parent page (listener2) Register listener for aChanged that applies CSS changes to #selectorA (listener3) Intended On-Change Flow

问题 Reading a very interesting blog post by Dan Luu about advances in x86 architecture over the past few decades, he says: If we set _foo to 0 and have two threads that both execute incl (_foo) 10000 times each, incrementing the same location with a single instruction 20000 times, is guaranteed not to exceed 20000, but it could (theoretically) be as low as 2. If it’s not obvious why the theoretical minimum is 2 and not 10000, figuring that out is a good exercise. where _foo is some memory address

问题 I have an ugly race condition with a WPF usercontrol, which is some kind of extended ComboBox: The UserControl mainly defines two bindable DependencyProperties, one is the selected item, another one is a list, from which the selected item can be chosen. Both are bindable, so the control may be initialized with or without a selected item and both properties can be changed via binding (on DataContext change), further the selection may change due to user interaction. The UserControl contains a

问题 In the following code example, program execution never ends. It creates a thread which waits for a global bool to be set to true before terminating. There is only one writer and one reader. I believe that the only situation that allows the loop to continue running is if the bool variable is false. How is it possible that the bool variable ends up in an inconsistent state with just one writer ? #include <iostream> #include <pthread.h> #include <unistd.h> bool done = false; void * threadfunc1