Re: [boost] [interprocess][Shared memory]

From: Shibu Bera (shibu.ncst_at_[hidden])
Date: 2007-03-09 12:38:28

Thanks for the reply. I am sending the code and other details please view.

O/S :: linux fedora

filename : main.cpp

#include <boost/interprocess/allocators/allocator.hpp>
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <boost/interprocess/managed_shared_memory.hpp>

int main()
{
boost::interprocess::fixed_managed_shared_memory segment
                          (
                             boost::interprocess::open_or_create,
                              "MySharedMemory",       //segment name
                                1024 * 1024
                            );
  return 0;
}

command #  g++ -c main.cpp
command #  g++ g++ -o exec main.o -Wall -pedantic -g -pthread
-DBOOST_DATE_TIME_NO_LIB -lstdc++ -lboost_thread

/*linking without comman c++ */

command #  ./exec
command #  cp /dev/shm/MySharedMemory shm_without_ccpp

/* copy of shared memoty created */

command # rm /dev/shm/MySharedMemory

/* remove created shared memoty using comman line */

command # g++ -o exec main.o -Wall -pedantic -g -pthread
-DBOOST_DATE_TIME_NO_LIB -lstdc++ -lboost_thread -lxml2 -lccext2 -lccgnu2
-ldl

/* linking with comman c ++ */

command # ./exec
command # cp /dev/shm/MySharedMemory shm_with_ccpp

/* copy of shared memory created */

command # diff shm_without_ccpp shm_with_ccpp
Binary files shm_without_ccpp and shm_with_ccpp differ

Here I am comparing the two shared memories created. It says these are
different. I am not getting just adding a library in link time, how shared
memory is changed. Can I get some clue now?

On 3/9/07, Peter Dimov <pdimov_at_[hidden]> wrote:
>
> Shibu Bera wrote:
> > yes u r right. Linking another library is not important to use
> > interprocess. But because there is requirment of the other part of
> > the application I am including the link library of comman c++ while
> > creating executable , If I woudn't link comman c++, still shared
> > memory would have beed created.
> >
> > But including comman c++ link library, the shared memory is created is
> > different from the shared memory which is created without comman c++
> > link library. And in the shared memory I am finding offset of some
> > bytes on the actual value stored in the shared memory.
>
> Please post the two complete command lines.
>
> You may first try to add -lrt to the program that doesn't use the "common
> C++ library".
>
> Also, remove the -DBOOST_INTERPROCESS_POSIX_PROCESS_SHARED as Ion stated.
>
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