[Boost-users] boost::interprocess:basic_string : Capacity no more than 10

27 Jul 2009

      Hello, 

I first present to you my code and I will explain my problem with the code .

ShmString.h : 

namespace ip=boost::interprocess;
typedef ip::allocator<char, ip::managed_shared_memory::segment_manager>
CharAllocator;

class ShmString : public ip::basic_string<char, std::char_traits<char>,
CharAllocator >
{
	public:
		ShmString ();
		virtual ~ShmString ();

		/**
		 * The segment to build the string
		 */
		static ip::managed_shared_memory* st_segment;
}

This class served to have some string in memory. The following Element.h
used it : 

class Element
{
	public:
		Element (const std::string dir, const std::string type,
ip::managed_shared_memory * segment);

	private:
		ShmString dir;
		ShmString file;
		ShmString type;
		ip::managed_shared_memory * segment;
};

I have four attributes that declare it. When I tried to define all the
attributes in the constructor like this in Element.cpp : 

Element::Element (const string dir, const string file, const string type,
ip::managed_shared_memory *segment){
	try{
		this->dir.assign(dir.c_str());
		this->file.assign(file.c_str());
	}
	catch(ip::interprocess_exception &e){
		ostringstream oss;
		const std::string what(e.what());
		oss << "Class Element in constructor 1 -> ";
		oss << what;
		throw EventException(oss.str().c_str(), __LINE__ );
	}
}

	If for example "const string dir " has the size more than 10 (the capacity
by default for a ShmString object), I obtained an error like this : 

x0807436f in boost::interprocess::basic_string<char, std::char_traits<char>,
boost::interprocess::allocator<char,
boost::interprocess::segment_manager<char,
boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index>
...
...
::assign (this=0xb7428274,
s=0xb9adf154 <Address 0xb9adf154 out of bounds>)

	I tried to used the other constructors by default for basic_string but it
remains the same. This code only works when in the constructors the string
size are below 10. 

Could you someone explain me why I obtain this? Do I have some faulty code? 

Could you provide some examples on how store string with
interprocess::basic_string in shared memory for a size for more than 10
characters?

 I will be very grateful because I am lost... 

Thanks you in advance 

Regards 

Samuel 

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[Boost-users] boost::interprocess:basic_string : Capacity no more than 10

samuel.gallard