"Ninel Evol" <myLC@gmx.de> writes:
one thing that C++ is missing amongst many others is the possibility to abort a thread in a clean fashion (so that the thread itself, i.e. the object will do the cleanup). The need for this arises virtually every time you use a background thread for doing the work (for example computations). Currently, you can have the thread check for an abort request every once in a while (bad), or you can just kill that sucker and do the cleanup in the main thread (not that nice either). A clean alternative would be if the main thread were able to "provoke" an exception in the worker thread. This "abort- request-exception" could than be caught by the worker thread. It could thereby do the entire cleanup itself (object-oriented).
The current C++0x thread library proposal (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2320.html) includes request_cancellation(), which requests a thread cancel at the next call to cancellation_point() or one of the standard cancellation points (such as waiting on a condition variable). I intend to add this facility to Boost.thread once the move to subversion is complete.
I added a little example below. The example is for Windows and VCPP (sorry for that). You can do the same in Linux by stopping the thread via pthread_kill(id,SIGSTOP) and then manipulating the EIP (see thread_info.h), but of course it's a bit messy due to the kernel includes, etc...
This is very messy --- it's asynchronous, so will break all sorts of stuff. POSIX asynchronous thread cancellation has successfully demonstrated that it's a bad idea, except for very specific cases. Anthony -- Anthony Williams Just Software Solutions Ltd - http://www.justsoftwaresolutions.co.uk Registered in England, Company Number 5478976. Registered Office: 15 Carrallack Mews, St Just, Cornwall, TR19 7UL