Handling exceptions from thread functions

In the previous recipe, we introduced the thread support library and saw how to do some basic operations with threads. In that recipe, we briefly discussed exception handling in thread functions and mentioned that exceptions cannot leave the top-level thread function because they cause the program to abnormally terminate with a call to std::terminate(). On the other hand, exceptions can be transported between threads within an std::exception_ptr wrapper; in this recipe, we will see how to do this.

Getting ready

You are now familiar with the thread operations we discussed in the previous recipe, Working with threads. The exception_ptr class is available in the std namespace, which is in the <exception> header; mutex (which we will discuss in more detail in the next recipe) is also available in the same namespace but in the <mutex> header.

How to do it...

To properly handle exceptions thrown in a worker thread from the main thread or the thread...