Oh, and note another thing. Putting a block around the read stuff doesn't fix the problem. I had even originally moved it to another function. The crucial thing is that the writing objects go out of scope - presumably it's their destructors that clean things up?
-----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org]On Behalf Of Robert S. Grimes Sent: Monday, March 13, 2006 2:39 PM To: Boost-Users Subject: [Boost-users] [serialization] Problem writing and reading in sameblock, with work-around
Hi all,
It seems there is a problem with using both an output and an input archive in the same code block. Here is a simple sample that illustrates the problem. By defining the symbol BREAK_IT, you can see the problem; not defining it, the example works. What is particularly odd is that it is throwing an std::bad_alloc from within text_iarchive_impl<Archive>::load(std::string &s) in text_iarchive_impl.ipp because the requested size is obviously wrong - for example, 3435973837!!! I can't follow well enough what is happening, but I have figured out a work-around from noticing the differences between my example and demo.cpp; in the latter, the writing and reading of an archive are performed in two separate functions, or more precisely, two different blocks. Is this normal? Have I missed the documentation about this? Still, seems rather fussy, though to be honest, I'm not likely to suffer from the workaround in "production" code, but it's a bit unnerving nonetheless...
Thanks! -Bob
Example follows:
#include <fstream> #include <iostream> #include <string>
#include
#include class Simple { private: int anIntMember; bool aBoolMember;
template<class Archive> void serialize(Archive & ar, const unsigned int file_version) { ar & BOOST_SERIALIZATION_NVP(anIntMember) & BOOST_SERIALIZATION_NVP(aBoolMember); }
// Grant access to serialization library friend class boost::serialization::access;
public: Simple(): anIntMember(27), aBoolMember(false) {} int GetAnIntMember() const { return anIntMember; } void SetAnIntMember(int v) { anIntMember = v; } bool GetABoolMember() const { return aBoolMember; } void SetABoolMember(bool v) { aBoolMember = v; } };
#define BREAK_IT
void TestBoostText(const Simple& parms) { #ifndef BREAK_IT { #endif // Write out to boost archive std::ofstream ofs("./boost.txt"); boost::archive::text_oarchive oa(ofs); oa << parms; /// Could use a better XML element name #ifndef BREAK_IT } #endif
// Read it back and check Simple rparms; std::ifstream ifs("./boost.txt"); // THIS IS THE BROKEN LINE boost::archive::text_iarchive ia(ifs); ia >> rparms; std::cout << "Checking boost read..."; if (rparms.GetAnIntMember() == 99) { std::cout << "Worked!!!" << std::endl; } else { std::cout << "Failed - appears not to have been updated" << std::endl; } }
int main(int argc, char* argv[]) { Simple parms;
// Modify parms for testing purposes parms.SetAnIntMember(99);
// Test both binary archives TestBoostText(parms);
return 0; } _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users