Is there an occasion where using catch all clause : catch (...) is justified?

Question

Each time I have seen the catch all statement:

try 
{
  // some code 
}
catch (...)
{

}

it has always been an abuse.

The arguments against using cache all clauses are obvious. It will catch anything including OS generated exceptions such as access violations. Since the exception handler can't know what it's dealing with, in most cases the exceptions will manifest as obscure log messages or some incoherent message box.

So catch(...) seems inherently evil.

But it is still implemented in C++ and other languages (Java, C#) implements similar mechanisms. So is there some cases when its usage is justified?

Answer 1

(1) It's not true that the statement will catch OS exceptions. Your use of the term "Access Violation" betrays a Windows background; it was true for older MSVC++ versions.

(2) Regardsless, the catch-all behavior is useful for threads with specific purposes. Catching the failure allows the thread to report it failed. Without it, the other parts of the program need to deal with the possibility of a thread just disappearing. It also allows you to log which thread failed, and the arguments used to start the thread.