It looks like it’s not that null is treated as a NullPointerException, but that the act of attempting to throw null itself throws a NullPointerException. In other words, throw checks that its argument is nonnull, and if it is null, it throws a NullPointerException. JLS 14.18 specifies this behavior: If evaluation of the Expression completes … Read more
It’s somewhat weird to read but yes, the exception will bubble up to the calling code – but only if you await or Wait() the call to Foo. public async Task Foo() { var x = await DoSomethingAsync(); } public async void DoFoo() { try { await Foo(); } catch (ProtocolException ex) { // The … Read more
Your question makes an assertion, that “Writing exception-safe code is very hard”. I will answer your questions first, and then, answer the hidden question behind them. Answering questions Do you really write exception safe code? Of course, I do. This is the reason Java lost a lot of its appeal to me as a C++ … Read more
The difference is that when you use from, the __cause__ attribute is set and the message states that the exception was directly caused by. If you omit the from then no __cause__ is set, but the __context__ attribute may be set as well, and the traceback then shows the context as during handling something else … Read more
Simple: #include <stdexcept> int compare( int a, int b ) { if ( a < 0 || b < 0 ) { throw std::invalid_argument( “received negative value” ); } } The Standard Library comes with a nice collection of built-in exception objects you can throw. Keep in mind that you should always throw by value … Read more
You can trap unhandled exceptions at different levels: AppDomain.CurrentDomain.UnhandledException From all threads in the AppDomain. Dispatcher.UnhandledException From a single specific UI dispatcher thread. Application.Current.DispatcherUnhandledException From the main UI dispatcher thread in your WPF application. TaskScheduler.UnobservedTaskException from within each AppDomain that uses a task scheduler for asynchronous operations. You should consider what level you need to … Read more
What is the difference between the following ways of handling InterruptedException? What is the best way to do it? You’ve probably come to ask this question because you’ve called a method that throws InterruptedException. First of all, you should see throws InterruptedException for what it is: A part of the method signature and a possible … Read more
I use [NSException raise:format:] as follows: [NSException raise:@”Invalid foo value” format:@”foo of %d is invalid”, foo];
You can just do the following: var connection = System.Configuration.ConfigurationManager. ConnectionStrings[“Test”].ConnectionString; Your assembly also needs a reference to System.Configuration.dll
It makes a difference if you return early: try: run_code1() except TypeError: run_code2() return None # The finally block is run before the method returns finally: other_code() Compare to this: try: run_code1() except TypeError: run_code2() return None other_code() # This doesn’t get run if there’s an exception. Other situations that can cause differences: If an … Read more