try-finally

Best practice to do nested TRY / FINALLY statement

由 |▌冷眼眸甩不掉的悲伤 提交于 2019-11-27 17:53:39
Hi What is the best way to do nested try & finally statements in delphi? var cds1 : TClientDataSet; cds2 : TClientDataSet; cds3 : TClientDataSet; cds4 : TClientDataSet; begin cds1 := TClientDataSet.Create(application ); try cds2 := TClientDataSet.Create(application ); try cds3 := TClientDataSet.Create(application ); try cds4 := TClientDataSet.Create(application ); try /////////////////////////////////////////////////////////////////////// /// DO WHAT NEEDS TO BE DONE /////////////////////////////////////////////////////////////////////// finally cds4.free; end; finally cds3.free; end; finally

Why do we need the “finally” clause in Python?

由 ☆樱花仙子☆ 提交于 2019-11-27 16:36:11
I am not sure why we need finally in try...except...finally statements. In my opinion, this code block try: run_code1() except TypeError: run_code2() other_code() is the same with this one using finally : try: run_code1() except TypeError: run_code2() finally: other_code() Am I missing something? 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

What happens if both catch and finally blocks throw exception?

由 余生颓废 提交于 2019-11-27 11:30:55
问题 What happens if both catch and finally blocks throw exception? 回答1: When the finally block throws an exception, it will effectively hide the exception thrown from the catch block and will be the one ultimately thrown. It is therefore important to either log exceptions when caught, or make sure that the finally block does not itself throw an exception, otherwise you can get exceptions being thrown that are stifled and never seen. 回答2: When catch throws an exception, finally block will be run

Why does a return in `finally` override `try`?

由 落花浮王杯 提交于 2019-11-27 09:27:33
问题 How does a return statement inside a try/catch block work? function example() { try { return true; } finally { return false; } } I'm expecting the output of this function to be true , but instead it is false ! 回答1: Finally always executes. That's what it's for, which means it's return gets used in your case. You'll want to change your code so it's more like this: function example() { var returnState = false; // initialisation value is really up to the design try { returnState = true; } catch

Overhead of try/finally in C#?

由 匆匆过客 提交于 2019-11-27 05:24:05
问题 We've seen plenty of questions about when and why to use try / catch and try / catch / finally . And I know there's definitely a use case for try / finally (especially since it is the way the using statement is implemented). We've also seen questions about the overhead of try/catch and exceptions. The question I linked to, however, doesn't talk about the overhead of having JUST try-finally. Assuming there are no exceptions from anything that happens in the try block, what's the overhead of

Java Try Catch Finally blocks without Catch

由 北城以北 提交于 2019-11-26 23:57:17
I'm reviewing some new code. The program has a try and a finally block only. Since the catch block is excluded, how does the try block work if it encounters an exception or anything throwable? Does it just go directly to the finally block? If any of the code in the try block can throw a checked exception, it has to appear in the throws clause of the method signature. If an unchecked exception is thrown, it's bubbled out of the method. The finally block is always executed, whether an exception is thrown or not. Peter Lawrey A small note on try / finally : The finally will always execute unless

Best practice to do nested TRY / FINALLY statement

由 非 Y 不嫁゛ 提交于 2019-11-26 19:15:35
问题 Hi What is the best way to do nested try & finally statements in delphi? var cds1 : TClientDataSet; cds2 : TClientDataSet; cds3 : TClientDataSet; cds4 : TClientDataSet; begin cds1 := TClientDataSet.Create(application ); try cds2 := TClientDataSet.Create(application ); try cds3 := TClientDataSet.Create(application ); try cds4 := TClientDataSet.Create(application ); try /////////////////////////////////////////////////////////////////////// /// DO WHAT NEEDS TO BE DONE /////////////////////////

Why do we need the “finally” clause in Python?

由 房东的猫 提交于 2019-11-26 11:44:47
问题 I am not sure why we need finally in try...except...finally statements. In my opinion, this code block try: run_code1() except TypeError: run_code2() other_code() is the same with this one using finally : try: run_code1() except TypeError: run_code2() finally: other_code() Am I missing something? 回答1: 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:

Java Try Catch Finally blocks without Catch

由 拈花ヽ惹草 提交于 2019-11-26 09:16:22
问题 I\'m reviewing some new code. The program has a try and a finally block only. Since the catch block is excluded, how does the try block work if it encounters an exception or anything throwable? Does it just go directly to the finally block? 回答1: If any of the code in the try block can throw a checked exception, it has to appear in the throws clause of the method signature. If an unchecked exception is thrown, it's bubbled out of the method. The finally block is always executed, whether an

Why does changing the returned variable in a finally block not change the return value?

由 回眸只為那壹抹淺笑 提交于 2019-11-26 01:49:03
问题 I have a simple Java class as shown below: public class Test { private String s; public String foo() { try { s = \"dev\"; return s; } finally { s = \"override variable s\"; System.out.println(\"Entry in finally Block\"); } } public static void main(String[] xyz) { Test obj = new Test(); System.out.println(obj.foo()); } } And the output of this code is this: Entry in finally Block dev Why is s not overridden in the finally block, yet control printed output? 回答1: The try block completes with
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