std::set_terminate 和 std::set_unexpected

std::set_unexpected

当函数抛出的异常不在dynamic-exception-specification包含的时候。异常可以被set_unexpected的函数捕获，然后可以调用terminate函数或者其它的方法，比如 exit或者abort。当然也可以重新抛出异常，但如果新抛出的异常不在dynamic-exception-specification里面的话，terminate会默认执行。

example:

// set_unexpected example
#include        // std::cerr
#include       // std::set_unexpected

void myunexpected () {
  std::cerr << "unexpected called\n";
  throw 0;     // throws int (in exception-specification)
}

void myfunction () throw (int) {
  throw 'x';   // throws char (not in exception-specification)
}

int main (void) {
  std::set_unexpected (myunexpected);
  try {
    myfunction();
  }
  catch (int) { std::cerr << "caught int\n"; }
  catch (...) { std::cerr << "caught some other exception type\n"; }
  return 0;
}

output:

unexpected called
caught int

std::set_terminate

当throw的异常没有捕获的时候，会调用set_terminate设置的函数。

eg:

    // set_terminate example
    #include        // std::cerr
    #include       // std::set_terminate
    #include         // std::abort

    void myterminate () {
      std::cerr << "terminate handler called\n";
      abort();  // forces abnormal termination
    }

    int main (void) {
      std::set_terminate (myterminate);
      throw 0;  // unhandled exception: calls terminate handler
      return 0;
    }

output:

  terminate handler called
  Aborted