Using the C and C++ condition handling schemes together in a C++ program may result in undefined behavior. This applies to the use of try, throw and catch with signal() and raise(), with z/OS® Language Environment® condition handlers such as CEEHDLR, or with CICS HANDLE ABEND under CICS in 31-bit mode. The behavior with respect to running destructors for automatic objects is undefined, due to control being transferred to non-C++ exception handlers (such as signal handlers) and stacks being collapsed. If a C software exception is not handled and results in program termination, the behavior for destructors for static non-local objects will also be undefined.
With z/OS UNIX, in a multithreaded environment, z/OS XL C++ exception stacks are managed on a per-thread basis. This means an exception thrown on one thread cannot be caught on another thread, including the IPT where main() was started. If the exception is not handled by the thread from which it was thrown, then the terminate() function is called.