[Bug c++/59224] New: std::uncaught_exception always returns true after exception while constructing another exception.

["man2gm at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59224

            Bug ID: 59224
           Summary: std::uncaught_exception always returns true after
                    exception while constructing another exception.
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: man2gm at gmail dot com

This code prints (erroneously)

Hello, world!
1

in g++ 4.8.1, g++ 4.6.3, but works correctly in g++ 4.5.2.

cat main.cpp 
#include <string>
#include <iostream>


struct Exception
{
        std::string what;
        Exception(const std::string & what_) : what(what_) {}
};


std::string f()
{
        throw Exception("Hello, world!");
}

void g()
{
        try
        {
                f();
        }
        catch (...)
        {
                throw Exception(f());
        }
}


int main(int argc, char ** argv)
{
        try
        {
                g();
        }
        catch (const Exception & e)
        {
                std::cerr << e.what << std::endl;
        }

        /// returns 1 in gcc 4.6.3, 4.8.1 - bug
        std::cerr << std::uncaught_exception() << std::endl;

        return 0;
}


# g++-4.8 --version
g++-4.8 (Ubuntu 4.8.1-2ubuntu1~12.04) 4.8.1
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# g++-4.8 main.cpp
# ./a.out 
Hello, world!
1

# g++-4.6 --version
g++-4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# g++-4.6 main.cpp
# ./a.out 
Hello, world!
1

# g++-4.5 --version
g++-4.5 (Ubuntu/Linaro 4.5.2-8ubuntu4) 4.5.2
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# g++-4.5 main.cpp
# ./a.out 
Hello, world!
0


http://ideone.com/lx2ao2