Boost C++ Libraries: Ticket #3895: Faulty output of tags by diagnostic_information() in G++ MinGW

Wed, 03 Feb 2010 15:38:39 GMT

On closer inspection it seems to be due to the fact that typeid().name returns a system specific name. To demonstrate this change tag_type_name() to call the typeid() function and print to stdout:

    template <class T>
    inline
    char const *
    tag_type_name()
        {
#ifdef BOOST_NO_TYPEID
        return BOOST_CURRENT_FUNCTION;
#else
		std::cout<<typeid(T*).name();
        return typeid(T*).name();
#endif
        }

If this counts as a bug or a feature, I am now unsure, however it does not seem to be a problem with the library itself.

Emil Dotchevski — Wed, 03 Feb 2010 18:48:22 GMT

Yes, this is due to typeid.name(). Note that by design, the diagnostic_information string is not user-friendly and may not be pretty.

That said, since I don't have mingw handy, could you please run this code with the latest trunk version? It should look a lot better now.

Wed, 03 Feb 2010 19:45:54 GMT

Recompiled example_io.cpp with the trunk version (59443), seems to be working perfectly:

Caught 'read_error' exception.
-------------------------------------------------
Source file name: tmp1.txt
Destination file name: tmp2.txt
File name: tmp1.txt
OS error: 0
Failed function: fread
Output from diagnostic_information():
example_io.cpp(78): Throw in function void my_fread(void*, size_t, size_t, const
 boost::shared_ptr<_iobuf>&)
Dynamic exception type: boost::exception_detail::clone_impl<fread_error>
std::exception::what: example_io error
[tag_file_name_dst*] = tmp2.txt
[tag_file_name_src*] = tmp1.txt
[boost::errinfo_errno_*] = 0, "No error"
[boost::errinfo_file_name_*] = tmp1.txt
[boost::errinfo_file_handle_*] = [ type: N5boost10error_infoINS_20errinfo_file_h
andle_ENS_8weak_ptrI6_iobufEEEE, size: 12, dump: 68 67 49 00 b8 09 17 77 58 0f 3
3 00 ]
[boost::errinfo_api_function_*] = fread
Caught 'open_error' exception.
-------------------------------------------------
File name: tmp1.txt
OS error: 2
Failed function: fopen
Output from diagnostic_information():
example_io.cpp(67): Throw in function boost::shared_ptr<_iobuf> my_fopen(const c
har*, const char*)
Dynamic exception type: boost::exception_detail::clone_impl<fopen_error>
std::exception::what: example_io error
[boost::errinfo_errno_*] = 2, "No such file or directory"
[boost::errinfo_file_name_*] = tmp1.txt
[boost::errinfo_api_function_*] = fopen
[boost::errinfo_file_open_mode_*] = rb

status changed

Emil Dotchevski — Wed, 03 Feb 2010 20:20:07 GMT

status new → assigned

Ah, not entirely perfect, a bit of mangling can be seen in the boost::errinfo_file_handle_ value. Should be good in trunk revision #59449.

Thu, 04 Feb 2010 17:41:35 GMT

Tried with latest trunk version, all fine now:

Caught 'read_error' exception.
-------------------------------------------------
Source file name: tmp1.txt
Destination file name: tmp2.txt
File name: tmp1.txt
OS error: 0
Failed function: fread
Output from diagnostic_information():
example_io.cpp(78): Throw in function void my_fread(void*, size_t, size_t, const
 boost::shared_ptr<_iobuf>&)
Dynamic exception type: boost::exception_detail::clone_impl<fread_error>
std::exception::what: example_io error
[tag_file_name_dst*] = tmp2.txt
[tag_file_name_src*] = tmp1.txt
[boost::errinfo_errno_*] = 0, "No error"
[boost::errinfo_file_name_*] = tmp1.txt
[boost::errinfo_file_handle_*] = [ type: boost::error_info<boost::errinfo_file_h
andle_, boost::weak_ptr<_iobuf> >, size: 12, dump: 68 67 49 00 b8 09 17 77 58 0f
 25 00 ]
[boost::errinfo_api_function_*] = fread
Caught 'open_error' exception.
-------------------------------------------------
File name: tmp1.txt
OS error: 2
Failed function: fopen
Output from diagnostic_information():
example_io.cpp(67): Throw in function boost::shared_ptr<_iobuf> my_fopen(const c
har*, const char*)
Dynamic exception type: boost::exception_detail::clone_impl<fopen_error>
std::exception::what: example_io error
[boost::errinfo_errno_*] = 2, "No such file or directory"
[boost::errinfo_file_name_*] = tmp1.txt
[boost::errinfo_api_function_*] = fopen
[boost::errinfo_file_open_mode_*] = rb

status changed; resolution set

Emil Dotchevski — Thu, 04 Feb 2010 18:40:41 GMT

status assigned → closed
resolution → fixed

Thanks, Andrew.