Odd clang result using stringstream formatted input

Clang Frontend
1

The following program:

#include <iostream>
#include <sstream>
#include <stdexcept>
int main()
     {
  
     std::stringstream ss;
     ss.exceptions(std::ios_base::failbit | std::ios_base::badbit);
     char c;

     try
         {
         ss >> c;
         std::cout << "Exception not thrown.";
         }
     catch (std::runtime_error &)
         {
         std::cout << "Exception std::runtime_error thrown.";
         }
     catch (...)
         {
         std::cout << "Unknown exception thrown.";
         }
     }

outputs "Unknown exception thrown." when compiled and linked with the latest clang built from source on Windows 7. The compilation options are:

-c -x c++ -Wno-unused-local-typedef -Wno-dll-attribute-on-redeclaration -O0 -g -fno-inline -Wall -g -march=i686 -m32 -o

The linker options are:

-Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -g -march=i686 -m32

I would have expected the output to be "Exception std::runtime_error thrown." as it is when compiled with VC++ 14.

Is clang following the C++ standard or is this a bug in clang ?

2

I can't reproduce this on Linux with libc++, using quite recent SVN
versions.

1. Could you try with -std=c++11? Looking at [1], that particular
inheritance is specific to C++11 and newer.

2. Which clang version are you using?

[1]:std::ios_base::failure - cppreference.com

3

The following program:

#include <iostream>
#include <sstream>
#include <stdexcept>
int main()
     {
  
     std::stringstream ss;
     ss.exceptions(std::ios_base::failbit | std::ios_base::badbit);
     char c;

     try
         {
         ss >> c;
         std::cout << "Exception not thrown.";
         }
     catch (std::runtime_error &)
         {
         std::cout << "Exception std::runtime_error thrown.";
         }
     catch (...)
         {
         std::cout << "Unknown exception thrown.";
         }
     }

outputs "Unknown exception thrown." when compiled and linked with the
latest clang built from source on Windows 7. The compilation options are:

-c -x c++ -Wno-unused-local-typedef -Wno-dll-attribute-on-redeclaration
-O0 -g -fno-inline -Wall -g -march=i686 -m32 -o

The linker options are:

-Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -g -march=i686 -m32

I would have expected the output to be "Exception std::runtime_error
thrown." as it is when compiled with VC++ 14.

Is clang following the C++ standard or is this a bug in clang ?

I can't reproduce this on Linux with libc++, using quite recent SVN
versions.

1. Could you try with -std=c++11? Looking at [1], that particular
inheritance is specific to C++11 and newer.

Same result with -std=c++11.

2. Which clang version are you using?

Built from source so it would be 4.0.

[1]:std::ios_base::failure - cppreference.com

Thanks I see that now. However if the above is changed to adding:

     catch (std::ios_base::failure &)
         {
         std::cout << "Exception std::ios_base::failure thrown.";
         }

before the:

     catch (std::runtime_error &)
         {
         std::cout << "Exception std::runtime_error thrown.";
         }

in the example above, the output is still

"Unknown exception thrown."

4

Seems like a mingw-ish bug. This program works as expected in an MSVC environment. I don’t have a 32-bit mingw installation to reproduce your configuration.

5

Seems like a mingw-ish bug. This program works as expected in an MSVC
environment. I don't have a 32-bit mingw installation to reproduce your
configuration.

It's my error. The std::ios_base::failure exception is derived from std::runtime_error only for c++11. In VC++ c++11 mode is automaically on whereas in clang the default is c++03 mode.