int main ()
{
using namespace hexerboost::interprocess;
//Typedefs
typedef managed_shared_memory::segment_manager SegmentManager;
typedef allocator<char, SegmentManager> CharAllocator;
typedef basic_string<char, std::char_traits<char>
,CharAllocator> MyShmString;
typedef allocator<MyShmString, SegmentManager> StringAllocator;
typedef vector<MyShmString, StringAllocator> MyShmStringVector;
//Remove shared memory on construction and destruction
struct shm_remove
{
//<-
#if 1
shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
#else
//->
shm_remove() { shared_memory_object::remove("MySharedMemory"); }
~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
//<-
#endif
//->
} remover;
//<-
(void)remover;
//->
//<-
#if 1
managed_shared_memory shm(create_only, test::get_process_id_name(), 65536);
#else
//->
managed_shared_memory shm(create_only, "MySharedMemory", 10000);
//<-
#endif
//->
//Create allocators
CharAllocator charallocator (shm.get_segment_manager());
StringAllocator stringallocator(shm.get_segment_manager());
//Create a vector of strings in shared memory.
MyShmStringVector *myshmvector =
shm.construct<MyShmStringVector>("myshmvector")(stringallocator);
//Insert 50 strings in shared memory. The strings will be allocated
//only once and no string copy-constructor will be called when inserting
//strings, leading to a great performance.
MyShmString string_to_compare(charallocator);
string_to_compare = "this is a long, long, long, long, long, long, string...";
myshmvector->reserve(50);
for(int i = 0; i < 50; ++i){
MyShmString move_me(string_to_compare);
//In the following line, no string copy-constructor will be called.
//"move_me"'s contents will be transferred to the string created in
//the vector
myshmvector->push_back(hexerboost::move(move_me));
//The source string is in default constructed state
assert(move_me.empty());
//The newly created string will be equal to the "move_me"'s old contents
assert(myshmvector->back() == string_to_compare);
}
//Now erase a string...
myshmvector->pop_back();
//...And insert one in the first position.
//No string copy-constructor or assignments will be called, but
//move constructors and move-assignments. No memory allocation
//function will be called in this operations!!
myshmvector->insert(myshmvector->begin(), hexerboost::move(string_to_compare));
//Destroy vector. This will free all strings that the vector contains
shm.destroy_ptr(myshmvector);
return 0;
}
int main ()
{
using namespace boost::interprocess;
//Typedefs
typedef allocator<char, managed_shared_memory::segment_manager>
CharAllocator;
typedef basic_string<char, std::char_traits<char>, CharAllocator>
MyShmString;
typedef allocator<MyShmString, managed_shared_memory::segment_manager>
StringAllocator;
typedef vector<MyShmString, StringAllocator>
MyShmStringVector;
//Open shared memory
//Remove shared memory on construction and destruction
struct shm_remove
{
//<-
#if 1
shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
#else
//->
shm_remove() { shared_memory_object::remove("MySharedMemory"); }
~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
//<-
#endif
//->
} remover;
//<-
(void)remover;
//->
//<-
#if 1
managed_shared_memory shm(create_only, test::get_process_id_name(), 10000);
#else
//->
managed_shared_memory shm(create_only, "MySharedMemory", 10000);
//<-
#endif
//->
//Create allocators
CharAllocator charallocator (shm.get_segment_manager());
StringAllocator stringallocator(shm.get_segment_manager());
//This string is in only in this process (the pointer pointing to the
//buffer that will hold the text is not in shared memory).
//But the buffer that will hold "this is my text" is allocated from
//shared memory
MyShmString mystring(charallocator);
mystring = "this is my text";
//This vector is only in this process (the pointer pointing to the
//buffer that will hold the MyShmString-s is not in shared memory).
//But the buffer that will hold 10 MyShmString-s is allocated from
//shared memory using StringAllocator. Since strings use a shared
//memory allocator (CharAllocator) the 10 buffers that hold
//"this is my text" text are also in shared memory.
MyShmStringVector myvector(stringallocator);
myvector.insert(myvector.begin(), 10, mystring);
//This vector is fully constructed in shared memory. All pointers
//buffers are constructed in the same shared memory segment
//This vector can be safely accessed from other processes.
MyShmStringVector *myshmvector =
shm.construct<MyShmStringVector>("myshmvector")(stringallocator);
myshmvector->insert(myshmvector->begin(), 10, mystring);
//Destroy vector. This will free all strings that the vector contains
shm.destroy_ptr(myshmvector);
return 0;
}
