Boost binary serialization

Question

I have a problem using forced serialization using binary archives. It works when using a file stream, but I want to save it in my local variable and eventually save / load it to / from berkeley db. When I run the program, I get boost :: archive :: archive_exception: "stream error" when creating the binary_iarchive instance.

#include <sys/time.h>
#include <string>
#include <boost/serialization/serialization.hpp>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <fstream>
#include <sstream>

namespace boost {
namespace serialization {

template<class Archive>
void serialize(Archive & ar, timeval & t, const unsigned int version)
{
    ar & t.tv_sec;
    ar & t.tv_usec;
}

}//namespace serialization
}//namespace boost


int main(int, char**)
{
    timeval t1;
    gettimeofday(&t1, NULL);
    char buf[256];

    std::stringstream os(std::ios_base::binary| std::ios_base::out| std::ios_base::in);
    {
        boost::archive::binary_oarchive oa(os, boost::archive::no_header);
        oa << t1;
    }

    memcpy(buf, os.str().data(), os.str().length());
    if(memcmp(buf, os.str().data(), os.str().length()) != 0)
        printf("memcpy error\n");

    timeval t2;
    {
        std::stringstream is(buf, std::ios_base::binary| std::ios_base::out| std::ios_base::in);

        boost::archive::binary_iarchive ia(is, boost::archive::no_header);
        ia >> t2;
    }

    printf("Old(%d.%d) vs New(%d.%d)\n", t1.tv_sec, t1.tv_usec, t2.tv_sec, t2.tv_usec);

    return 0;
}

This works when initialization is done using os.str (), so I assume that my way of copying data to my buffer or to the wrong one.

Answer 1

, . data() \0. c-. , stringstream char * ( ?), , , , , \0.

? ++-. os.str().

: \0, std::string (char *) . ( ). std::string buf .

std::stringstream is(std::string(buf, buf+os.str().length()), flags);