© 2023 Bloomberg Finance L.P. All rights reserved. Exceptionally Bad: The story on the misuse of exceptions and how to do better Core C++ June 7, 2023 Pete Muldoon Senior Engineering Lead© 2023 Bloomberg Bloomberg Finance L.P. All rights reserved. Exceptionally Bad: The story on the misuse of exceptions and how to do better Core C++ June 7, 2023 Pete Muldoon Senior Engineering Lead Exceptions in C++ object when found and throws an exception when its missing 54 Bloomberg Exceptionally Hard to find55 Bloomberg Exceptionally Hard to find Order findOrder(unsigned int id) { auto it = orders.find(id);

exceptional situations, however, can lead to unpredictable app behavior. The worst case is you miss an exceptionally rare occurrence during normal app operation, but the code doesn’t crash, and you have no logging

consistency that the platform approach brings. Benefits of the platform approach Platforms are exceptionally good at making components repeatable and reusable. This trait is especially useful when an application

Instead Redesigning Legacy Systems : Keys to success Managing External APIs in Enterprise Systems Exceptionally Bad : The Story on the Misuse of Exceptions and How to Do Better (Exceptions in C++ : Better Design

exceptions without explicitly using a try/catch block: When �ow collection completes (normally or exceptionally) it may need to execute an action. As you may have already noticed, it can be done in two ways: the lambda that can be used to determine whether the �ow collection was completed normally or exceptionally. In the following example the foo() �ow throws an exception after emitting the number 1: Flow runBlocking { foo() .onCompletion { cause -> if (cause != null) println("Flow completed exceptionally") } .catch { cause -> println("Caught exception") } .collect { value -> println(value)

src 指向 CF1。 3. 观察者 Completion 中的 fn 属性：用来存储具体的等待被回调的函数。这里需 要注意的是不同的回调方法（thenAccept、thenApply、exceptionally 等）接 收的函数类型也不同，即 fn 的类型有很多种，在上面的例子中 fn 指向 fn2。 3.3.2 整体流程 3.3.2.1 一元依赖 这里仍然以 thenApply 为例来说明一元依赖的流程： 由于异步执行的任务在其他线程上执行，而异常信息存储在线程栈中，因此当前线程 除非阻塞等待返回结果，否则无法通过 try\catch 捕获异常。CompletableFuture 提供了异常捕获回调 exceptionally，相当于同步调用中的 try\catch。使用方法如 下所示： @Autowired private WmOrderAdditionInfoThriftService wmOrder erIdAsync(orderId);// 业务方法，内部会发起异步 rpc 调用 return remarkResultFuture .exceptionally(err -> {// 通过 exceptionally 捕获异常，打印日志并返回默 认值 log.error(“WmOrderRemarkService.getCancelTypeAsync Exception

support any of the inputs in .loc and .iloc. .ix also supports floating point label schemes. .ix is exceptionally useful when dealing with mixed positional and label based hierachical indexes. However, when support any of the inputs in .loc and .iloc. .ix also supports floating point label schemes. .ix is exceptionally useful when dealing with mixed positional and label based hierachical indexes. However, when support any of the inputs in .loc and .iloc. .ix also supports floating point label schemes. .ix is exceptionally useful when dealing with mixed positional and label based hierachical indexes. However, when

you saturate a network link. • EBS volumes have unreliable performance. I/O performance can be exceptionally slow, causing the system to backload reads and writes until the entire cluster becomes unresponsive

gross margins exceeding 70% in 2020, in addition to NDR exceeded 120%, with GitLab performing exceptionally well, with an NDR of 152%. 图表 1：部分开源企业的上市表现 Figure 1: IPO performance of selected

IllegalStateException: Collected 2 Flow completion When flow collection completes (normally or exceptionally) it may need to execute an action. As you may have already noticed, it can be done in two ways: the lambda that can be used to determine whether the flow collection was completed normally or exceptionally. In the following example the simple flow throws an exception after emitting the number 1: import runBlocking { simple() .onCompletion { cause -> if (cause != null) println("Flow completed exceptionally") } .catch { cause -> println("Caught exception") } .collect { value -> println(value)