[Boost-users] [Serialization]Substituting std::istringstream for text_iarchive?

Subject: [Boost-users] [Serialization]Substituting std::istringstream for text_iarchive?
From: Laszlo Orban (contiboost_at_[hidden])
Date: 2010-05-05 04:49:28

We have encountered a problem during deserialization via
boost::archive::text_iarchive. It is somehow related to the gcc (4.4.1 via
MinGW) Windows implementation of the std::stream, that is the parameter of
the constructor of text_iarchive. The exact same code caused no problems on
a Linux machine (with gcc 4.4.1 as well). The setup is a multi-threaded
application (that causes the issue) with frequent deserializations on
different threads. The problem is in short:

1: MessagePtr msg; // the structure to be deserialized below
2: std::istringstream archive_stream(buffer); // buffer contains the data,
it is a simple char[] array
3: boost::archive::text_iarchive archive(archive_stream, 0); //constructor
of the text_iarchive for deserialize
4: archive >> msg; // the deserialization

The line causing the problem is the second and third one: in the MinGW
implementation of istringstream handling there seems to be some static
variables working in the background, and without proper protection of these
lines, eventually the application is terminated improperly. Important, that
the buffer above is thread-binded, thus it is surely not modified in the
background. Using global boost::mutex-es solve the problem:

boost::mutex istringstream_locker; //global , local mutexes doesn't work as
the behaviour is bound to the std::stream implementation
(...)
istringstream_locker.lock();
std::istringstream archive_stream(buffer);
boost::archive::text_iarchive archive(archive_stream, 0);
istringstream_locker.unlock();
(...)

However this being a frequently used code, we are wondering if there is any
better (more time effective) solution or workaround. (Note: we tried using
the boost/format/alt_sstream, but we couldn't get it to work.) Or maybe we
can substitute text_iarchive with something else that doesnt require an
std::stream?

Thanks for reading this!