因为人们可以使用boost的 find
方式 managed_shared_memory
,比如。
res = segment.find<MyType> ("name");
有没有一种方法可以列出某段定义的所有共享内存对象的名称?我需要它来调试,但没有找到boost的API。
你可以使用 named_begin()
和 named_end()
迭代器。
一个小的demo,它可以创建各种随机长度的字符串向量,并报告它找到了多少个。
#include <boost/interprocess/managed_mapped_file.hpp>
#include <boost/interprocess/containers/string.hpp>
#include <boost/interprocess/containers/vector.hpp>
#include <boost/container/scoped_allocator.hpp>
#include <iostream>
#include <vector>
namespace bip = boost::interprocess;
using Mem = bip::managed_mapped_file;
template <typename T = void>
using Alloc = boost::container::scoped_allocator_adaptor<
bip::allocator<T, Mem::segment_manager> >;
using String = boost::container::basic_string<char, std::char_traits<char>, Alloc<char> >;
template <typename T>
using Vector = boost::container::vector<T, Alloc<T> >;
int main() {
auto mf = Mem(bip::open_or_create, "test.bin", 20ul<<30);
std::cout << "Named #" << mf.get_segment_manager()->get_num_named_objects() << "\n";
using Container = Vector<String>;
for (auto to_create: {"foo", "bar", "qux"}) {
auto& c = *mf.find_or_construct<Container>(to_create)(mf.get_segment_manager());
auto n = rand()%10;
for (int i = 0; i<n; ++i) {
c.emplace_back(std::to_string(i*i));
}
}
std::cout << "Named #" << mf.get_segment_manager()->get_num_named_objects() << "\n";
for (auto it = mf.named_begin(); it != mf.named_end(); ++it) {
std::string_view name(it->name(), it->name_length());
std::cout << "Item " << name << " has " <<
reinterpret_cast<Container const*>(it->value())->size() << " elements\n";
}
}
印刷品
Named #0
Named #3
Item bar has 6 elements
Item foo has 3 elements
Item qux has 7 elements
当然,我并不鼓励大家使用 "我"。reinterpret_cast
. 使用 find_or_construct
像平常一样的界面。