On 10 August 2015 at 20:01, John Saxton <john.saxton@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > My organization recently upgraded to C++11 and we're running into a > problem. We use the POSIX threading library, and in some rare cases > (pthread_join doesn't exit within a specified timeout, for example), > we'll kill a thread via pthread_cancel. In C++, thread cancellation is > implemented via the abi::__forced_unwind exception[1], and in C++03, > this worked well for us. > > In C++11, all destructors are noexcept(true) by default. So if you try > to cancel a thread that's in a destructor, the abi::__forced_unwind > exception will escape the destructor, std::terminate() will be > invoked, and your program dies. I have written a simple program that > can reproduce this.[2] Yes, I've been aware of this problem for some time, and don't have any solution. > What's the best way to solve this problem? I could avoid using > pthread_cancel, but I was hoping to be able to upgrade to C++11 > without making major changes like that. I could flag all my > destructors as noexcept(false), but that's tedious and doesn't cover > third party code like the STL or Boost. I briefly looked into > std::thread, but it looks like std::thread doesn't have a cancellation > mechanism. I have reproduced this with a couple of different libstdc++ > versions (4.8.4-2ubuntu1~14.04 being the newest package I have tested > with). Would upgrading to a newer version fix my problem? No, the problem is inherent to using forced_unwind in C++11. > Any other > ideas? Do I just need to accept the fact that C++11 broke POSIX thread > cancellation and there's always going to be a chance that > pthread_cancel will cause my application to terminate? Yes, or accept that you shouldn't use pthread_cancel in C++11. I don't have any better suggestions, sorry.
