On Mon, 25 Nov 2013 11:48:19 +0100, Steven Maenhout wrote:

Hello,

I'm trying to open a boost::iostreams::stream in the constructor of a class and to close the stream in the destructor. This works fine but when I pass a reference to a std::stringstream in that same constructor I get a segmentation fault in the destructor when I flush or close the stream. This happens irrespective if the passed std::stringstream reference takes part in the boost::iostream::stream or not.

I'm using gcc 4.6.3 with boost 1.53 on Linux x86_64.

Below I provided a small example that exhibits this behaviour.

Any ideas anyone?

#include "test.h"

int main(int argc, char **argv) {

std::stringstream logStream; Test test(logStream); return 0; }

where test.h contains:

#include <fstream> #include <sstream> #include #include

typedef boost::iostreams::tee_device TeeDevice; typedef boost::iostreams::stream<TeeDevice> TeeStream;

class Test {

public: Test(const std::stringstream& logStream) {

std::ofstream dummyFileHandle("/dev/null", std::ios_base::out | std::ios_base::app); std::stringstream logStream2; TeeDevice myTee (logStream2, dummyFileHandle); m_out.open(myTee); } virtual ~Test() {

if(m_out.is_open()) { m_out.flush(); m_out.close(); } }; protected: TeeStream m_out; };

Hi Steven, I don't know boost::iostream, but valgrind shows that failure occurs because destructor attempts to dereference the memory, which was allocated on the stack. Moving dummyFileHandle and logStream2 into global scope fixes the crash. I guess, you cannot pass temporaries into TeeDevice constructor and have to hold dummyFileHandle and logStream2 alive as long as they are referenced in TeeDevice (making them class members accessed through shared_ptr perhaps?). Regards, Slava