[serialization] additional archive exception reporting
Hi all In order to assist my troubleshooting, I wrote a free function called 'extraArchiveWhat' which adds to the sometimes obscure (to me anyway) comments thrown by Boost.Serialization. John Pye-4 wrote:
Vaguely related comment on your problem. I was also recently seeing this "unregistered void cast" runtime error. As far as I could tell it was a problem relating to my ordering and placement of "#include
(or ditto iarchive), and "#include as well as calls to BOOST_CLASS_EXPORT. It was nothing to do with my use of void_cast_register, which in fact I don't use anywhere in any of my code.
So FWIW I think that this error message is not particularly helpful or well-worded.
Here is my client code first (the typedef enables me to
switch between text, XML, and platform-specific binary):
8<--------------------------------------
typedef boost::archive::xml_oarchive output_archive_type;
const char* cfilename = filename.c_str(); // convert to C-style string
...
try
{
std::ifstream ifs(cfilename, std::ios::binary);
if ( !ifs ) // see note below
{
std::cout << "** ofstream open failed: " << cfilename
<< std::endl;
}
input_archive_type ar(ifs); // see above typedef
ar & boost::serialization::make_nvp("container", container);
}
catch (const boost::archive::archive_exception& ae)
{
std::cout << "** boost::archive load exception"
<< ": " << __FILE__ << ":" << __LINE__ << ":" << __func__
<< ": " << ae.what() << "\n"
<< " " << extraArchiveWhat(ae.what())
<< std::endl;
}
-------------------------------------->8
Note that C++ stream io operations do not throw
exceptions. Each stream keeps its own mask of error
bits known as its "io state", accessible via rdstate().
In addition, each stream object can also be treated as
a Boolean value representing good (true) or faulty
(false).
Note too that __FILE__, __LINE__, and __func__ are
built-in macros which give the current source file
name, line number, and invoked call, respectively.
Now the helper function itself:
8<--------------------------------------
std::string // an interpretation based on my experiences
extraArchiveWhat
(const std::string what) // that is, the string returned by what()
{
std::string ret = "no local interpretation";
if ( what == "coding error" )
ret = "Boost.Serialization library problem";
else if ( what == "unrecognized XML syntax" )
ret = "name-value-pair name contains illegal chars including whitespace?";
else if ( what == "unregistered class" )
ret = "missing BOOST_CLASS_EXPORT(SubClass) macro?";
else if ( what == "unregistered void cast" )
ret = "missing ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(BaseClass) statement?";
else if ( what == "stream error" )
ret = "asymmetric serialization, including attempt to load empty archive?";
ret = "(" + ret + ")"; // add parentheses
return ret;
}
-------------------------------------->8
Hence a typical message might read:
** boost::archive load exception: main.cpp:101:main: unregistered void cast
(missing ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(BaseClass) statement?)
Finally, here is a list of possible exceptions copied
(with minor tweaks) from the relevant Boost.Serialization
headers:
// From
participants (1)
-
Robbie Morrison