1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2006-2007. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
//[doc_move_containers
#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/containers/vector.hpp>
#include <boost/interprocess/containers/string.hpp>
#include <boost/interprocess/allocators/allocator.hpp>
#include <cassert>
int main ()
{
using namespace boost::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 old shared memory and create new one
shared_memory_object::remove("myshm");
try{
managed_shared_memory shm(create_only, "myshm", 10000);
//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(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(), move(string_to_compare));
//Destroy vector. This will free all strings that the vector contains
shm.destroy_ptr(myshmvector);
}
catch(...){
shared_memory_object::remove("myshmvector");
throw;
}
shared_memory_object::remove("myshmvector");
return 0;
}
//]
#include <boost/interprocess/detail/config_end.hpp>
|
