how to get message of catch-all exception [duplicate]

Answer 1

I think he wants to make it log that an error occurred, but doesn't specifically need the exact error (he would write his own error text in that case).

The link DumbCoder posted above has at tutorial that will help you get what you're trying to achieve.

Answer 2

There's no way to know anything about the specific exception in a catch-all handler. It's best if you can catch on a base class exception, such as std::exception, if at all possible.

Answer 3

A caught exception is accessible by the function std::current_exception(), which is defined in <exception>. This was introduced in C++11.

std::exception_ptr current_exception();

However, std::exception_ptr is an implementation-defined type, so you can't get to the details anyway. typeid(current_exception()).name() tells you exception_ptr, not the contained exception. So about the only thing you can do with it is std::rethrow_exception(). (This functions seems to be there to standardize catch-pass-and-rethrow across threads.)

Answer 4

You can't get any details. The whole point of catch(...) is to have such "I don't know what can happen, so catch whatever is thrown". You usually place catch(...) after catch'es for known exception types.

Answer 5

You can't get any information out of the ... catch block. That is why code usually handles exceptions like this:

try
{
    // do stuff that may throw or fail
}
catch(const std::runtime_error& re)
{
    // speciffic handling for runtime_error
    std::cerr << "Runtime error: " << re.what() << std::endl;
}
catch(const std::exception& ex)
{
    // speciffic handling for all exceptions extending std::exception, except
    // std::runtime_error which is handled explicitly
    std::cerr << "Error occurred: " << ex.what() << std::endl;
}
catch(...)
{
    // catch any other errors (that we have no information about)
    std::cerr << "Unknown failure occurred. Possible memory corruption" << std::endl;
}