There are some articles concluding "never throw an exception from a destructor", and "std::uncaught_exception() is not useful", for example:

• http://www.gotw.ca/gotw/047.htm (written by Herb Sutter)

But it seems that I am not getting the point. So I wrote a small testing example (see below).

Since everything is fine with the testing example I would very appreciate some comments regarding what might be wrong with it.

testing results:

./main

Foo::~Foo(): caught exception - but have pending exception - ignoring
int main(int, char**): caught exception: from int Foo::bar(int)

./main 1

Foo::~Foo(): caught exception -  but *no* exception is pending - rethrowing
int main(int, char**): caught exception: from Foo::~Foo()

// file main.cpp
// build with e.g. "make main"
// tested successfully on Ubuntu-Karmic with g++ v4.4.1
#include <iostream>

class Foo {
  public:

  int bar(int i) {
    if (0 == i)
      throw(std::string("from ") + __PRETTY_FUNCTION__);
    else
      return i+1;
  }

  ~Foo() {
    bool exc_pending=std::uncaught_exception();
    try {
      bar(0);
    } catch (const std::string &e) {
      // ensure that no new exception has been created in the meantime
      if (std::uncaught_exception()) exc_pending = true;

      if (exc_pending) {
        std::cerr << __PRETTY_FUNCTION__ 
                  << ": caught exception - but have pending exception - ignoring"
                  << std::endl;
      } else {
        std::cerr << __PRETTY_FUNCTION__
                  << ": caught exception -  but *no* exception is pending - rethrowing"
                  << std::endl;
        throw(std::string("from ") + __PRETTY_FUNCTION__);
      }
    }
  }

};

int main(int argc, char** argv) {
  try {
    Foo f;
    // will throw an exception in Foo::bar() if no arguments given. Otherwise
    // an exception from Foo::~Foo() is thrown.
    f.bar(argc-1);
  } catch (const std::string &e) {
    std::cerr << __PRETTY_FUNCTION__ << ": caught exception: " << e << std::endl;
  }
  return 0;
}