finally | 易学教程

C++, __try and try/catch/finally

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问题 I'm wondering a bit about C++ try/catch/finally blocks. I've seen these commands with two underscores like __try. But MVSC 2010 projects also run without the underscores. So when do you need these underscores? 回答1: On Windows, exceptions are supported at the operating system level. Called Structured Exception Handling (SEH), they are the rough equivalent to Unix signals. Compilers that generate code for Windows typically take advantage of this, they use the SEH infrastructure to implement C++

Exception in catch block means the finally block never executes? [duplicate]

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问题 This question already has answers here : When is finally run if you throw an exception from the catch block? (7 answers) Finally block in try/catch not working? (4 answers) Try-Catch-Finally block problems with .NET4.5.1 (3 answers) Closed 2 years ago . I have a simple try-catch-finally block in C#. As I understand it, the "finally" block is useful because its code will execute even if an exception is thrown inside the catch block (barring some special exception types). However, in the simple

python之异常

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一、python的异常类型： https://fishc.com.cn/thread-45814-1-2.html 二、try,except,else,finally a=int('xyz')----------->ValueError: invalid literal for int() with base 10: 'xyz' b=1+'1'---------------->TypeError: unsupported operand type(s) for +: 'int' and 'str' f=open("jj.txt")------->FileNotFoundError: [Errno 2] No such file or directory: 'jj.txt' 以上代码可能执行的方案为：方案一：try--->except---->finaly 方案二：try--->else----->finally 总之，无论如何都会执行finally!!! 三、raise 来源： CSDN 作者： jiao_mrswang 链接： https://blog.csdn.net/jiao_mrswang/article/details/103667201

What's the `finally` keyword for in PHP?

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问题 Consider these two examples <?php function throw_exception() { // Arbitrary code here throw new Exception('Hello, Joe!'); } function some_code() { // Arbitrary code here } try { throw_exception(); } catch (Exception $e) { echo $e->getMessage(); } some_code(); // More arbitrary code ?> and <?php function throw_exception() { // Arbitrary code here throw new Exception('Hello, Joe!'); } function some_code() { // Arbitrary code here } try { throw_exception(); } catch (Exception $e) { echo $e-

Curious C# using statement expansion

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问题 I've run ildasm to find that this: using(Simple simp = new Simple()) { Console.WriteLine("here"); } generates IL code that is equivalent to this: Simple simp = new Simple(); try { Console.WriteLine("here"); } finally { if(simp != null) { simp.Dispose(); } } and the question is why the hell does it check null in the finally? The finally block will only be executed if the try block is executed, and the try block will only be executed if the Simple constructor succeeds (I.e. does not throw an

final，finally，finalize

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final：可以修饰属性，可以修饰方法（方法不能被重写，可以继承），可以修饰类（该类不能被继承，不能产生子类） finally：无论什么情况，都会执行 finalize：垃圾回收时，调用此方法来源： https://www.cnblogs.com/mataoblogs/p/10771063.html

Is it OK to catch Throwable for performing cleanup? [duplicate]

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问题 This question already has answers here : Is it a bad practice to catch Throwable? (14 answers) Closed 5 years ago . Take an example like this: public List<CloseableThing> readThings(List<File> files) throws IOException { ImmutableList.Builder<CloseableThing> things = ImmutableList.builder(); try { for (File file : files) { things.add(readThing(file)) } return things.build(); } catch (Throwable t) { for (CloseableThing thing : things.build()) { thing.close(); } throw t; } } A code review

Simulating finally block in C++0x

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问题 Inspired from the other topic, I wrote this code which simulates a finally block: #include <cassert> #include <iostream> struct base { virtual ~base(){} }; template<typename TLambda> struct exec : base { TLambda lambda; exec(TLambda l) : lambda(l){} ~exec() { lambda(); } }; class lambda{ base *pbase; public: template<typename TLambda> lambda(TLambda l): pbase(new exec<TLambda>(l)){} ~lambda() { delete pbase; } }; class A{ int a; public: void start(){ int a=1; lambda finally = [&]{a=2; std:

Difference between final keyword, finally block and finalized method in java throught one good example [duplicate]

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问题 This question already has answers here : In Java, what purpose do the keywords `final`, `finally` and `finalize` fulfil? (6 answers) Closed 4 years ago . Often these keywords confuse me. Can any one tell me exactly what the difference between them is? 回答1: final keyword class On a class it means you forbid to have a child class extending yours. public final class finalClass Attribute/Field final MyObject value = new MyObject() means you won't be able to modify the instance of the object.

Does 'finally' always execute in Python?

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问题 For any possible try-finally block in Python, is it guaranteed that the finally block will always be executed? For example, let’s say I return while in an except block: try: 1/0 except ZeroDivisionError: return finally: print("Does this code run?") Or maybe I re-raise an Exception : try: 1/0 except ZeroDivisionError: raise finally: print("What about this code?") Testing shows that finally does get executed for the above examples, but I imagine there are other scenarios I haven't thought of.