try-catch

问题 I ran a sample program and indeed destructors for stack-allocated objects are called, but is this guaranteed by the standard? 回答1: Yes, it is guaranteed (provided the exception is caught), down to the order in which the destructors are invoked: C++11 15.2 Constructors and destructors [except.ctor] 1 As control passes from a throw-expression to a handler, destructors are invoked for all automatic objects constructed since the try block was entered. The automatic objects are destroyed in the

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++

问题 Should I test if something is valid or just try to do it and catch the exception? Is there any solid documentation saying that one way is preferred? Is one way more pythonic ? For example, should I: if len(my_list) >= 4: x = my_list[3] else: x = 'NO_ABC' Or: try: x = my_list[3] except IndexError: x = 'NO_ABC' Some thoughts... PEP 20 says: Errors should never pass silently. Unless explicitly silenced. Should using a try instead of an if be interpreted as an error passing silently? And if so,

问题 Should I test if something is valid or just try to do it and catch the exception? Is there any solid documentation saying that one way is preferred? Is one way more pythonic ? For example, should I: if len(my_list) >= 4: x = my_list[3] else: x = 'NO_ABC' Or: try: x = my_list[3] except IndexError: x = 'NO_ABC' Some thoughts... PEP 20 says: Errors should never pass silently. Unless explicitly silenced. Should using a try instead of an if be interpreted as an error passing silently? And if so,

问题 Let's assume i got this code: internal static bool WriteTransaction(string command) { using (SqlConnection conn = new SqlConnection(SqlConnectionString)) { try { conn.Open(); using (SqlCommand cmd = new SqlCommand(command, conn)) cmd.ExecuteNonQuery(); } catch { return false; } } return true; } Well, i have placed conn's using outside the try / catch clause because SqlConnection 's constructor will not throw any exception (as it says). Therefore, conn.Open() is in the clause as it might throw

问题 Let's assume i got this code: internal static bool WriteTransaction(string command) { using (SqlConnection conn = new SqlConnection(SqlConnectionString)) { try { conn.Open(); using (SqlCommand cmd = new SqlCommand(command, conn)) cmd.ExecuteNonQuery(); } catch { return false; } } return true; } Well, i have placed conn's using outside the try / catch clause because SqlConnection 's constructor will not throw any exception (as it says). Therefore, conn.Open() is in the clause as it might throw

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

问题 If table column does not exist mysql shows error .How to fix it using try catch or error handling method Thanks 回答1: you can handle the mysql error in this way if ( ! $this->db->query('SELECT `name`,`age` FROM `example`')) { $error = $this->db->error(); // Has keys 'code' and 'message' } 来源： https://stackoverflow.com/questions/44732546/mysql-error-handling-try-catch

问题 I am still new to nodejs and developing my own asynchronous functions. According to the stack trace, I am looking at, I am being told that the following code is getting called back twice. Specifically the catch callback. Is there a better way to structure this so if more than one of the variables in the try blows up it only calls back once? As near as I can tell, since all of the buffer reads are done asynchronously if more than one error out they would all call the catch pretty much at the

问题 I am trying to create a program which asks the user to guess a number which is randomly generated and the loop exits when the input is correct. I am also trying to stop user from entering an invalid data and want the loop to repeat until user enters a valid data. The problem is when is type in an alphabet as an input, the program repeats. thank you for helping in advance. I am using eclipse kepler Output: Try guessing the number: k You have entered invalid data. Please try again Try guessing