id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
6711	with unordered_map using interprocess basic_string in shared memory, find and [] are annoying	jdy@…		"When using an interprocess basic string such as:

{{{
typedef boost::interprocess::allocator<
        char,
        boost::interprocess::managed_mapped_file::segment_manager
  >                                         char_allocator_t;

typedef boost::interprocess::basic_string<
        char, 
        std::char_traits<char>,
        char_allocator_t
  >                                      key_type;
}}}


map, flat_map (and unordered_map) all require that one have an externally created temporary of that type (key_type) created that can temporarily hold the results of a std::string or char*.  This requires code of the form:


{{{
      // A temporary string that allocates from the mapped file
      struct shm_clean { // cleanup shared memory on stack-unwind
        shm_clean() { 
          boost::interprocess::shared_memory_object::remove(""StupidSharedMemory"");
        }
        ~shm_clean() {
          boost::interprocess::shared_memory_object::remove(""StupidSharedMemory"");
        }
      } cleaner;
      boost::interprocess::managed_shared_memory
stupid(boost::interprocess::create_only ,""StupidSharedMemory"" ,500);
      key_type key_val(stupid.get_segment_manager());

mymap_in_shared_memory[key_val = mystring.c_str()] = junk;
}}}


This is barely ok when we are working with mutable memory regions, but when I am working in a read-only memory map, it is annoying.

Please see this thread:

http://thread.gmane.org/gmane.comp.lib.boost.devel/228874

Bug posted at request of Ion Gaztañaga

See sister ticked for boost::containers 

https://svn.boost.org/trac/boost/ticket/6710

Joel"	Feature Requests	closed	To Be Determined	None	Boost 1.49.0	Problem	wontfix	interprocess, unordered_map, container	jdy@… igaztanaga@…