boost-interprocess

问题 We have a scenario where we dynamically grow a memory mapped file used for boost's r-tree geometric index. We also make use of boost's interprocess memory mapped file api's. Mechanics are already sorted out in terms of unmapping the file, growing, and remapping - this all works. Thus far we've tried overestimating the size with a factor 10 of the inherent size of our coordinates, which works but is grossly over-estimated when inspecting with du . Is there some way to predict (worst-case or

问题 In the code below, I'm trying to initialize a managed_shared_memory object. When the constructor is invoked I see the below error message - terminate called after throwing an instance of 'boost::interprocess::interprocess_exception' what(): boost::interprocess_exception::library_error Aborted why is this exception being thrown? I'm running this on an ubuntu 16.04 linux OS, compiled the program using g++ 9.3.0. Boost version 1.58.0 struct test_obj { size_t x; size_t y; uint8_t buf[32]; bool is

问题 I need a way in C or C++ to get the free memory available from /dev/shm . Note that on my ARM architecure on Linux, unfortunately, ipcs reports a wrong max. available memory information, but df -h correctly gives me the current available memory from tmpfs . The problem is that I am trying to allocate shared memory via boost::interprocess::shared_memory_object::truncate , but this function does not throw when the memory is not available. This problem is not apparently in boost::interprocess ,

问题 I have a simple CPP class storing some configuration of my project. This class is stored using boost interprocess shared memory, and so can be accessed from different processes running on my server. Now, I would like to run some tests on my program- so I wish to mock the functionality of my shared-memory-object. In order to do that with gtest, I've created a base configuration class, which my mock class and my shared memory class will derive from. In order to use gtest correctly, the base's

问题 I want to make a lock free ring buffer in shared memory using runtime specified maximum number of entries. I am basing my code off an example I found in GitHub. I successfully created a lock free ring buffer in shared memory using this code. In my case, I need to specify the maximum number of entries that the ring buffer can accept at runtime construction and not at compile time per the example. The call to construct the shm::ring_buffer in the example is shown below. namespace bip = boost:

来源： https://stackoverflow.com/questions/18533527/boostinterprocess-shared-memory-between-32-and-64-bit-processes

问题 Consider the following situation: class Helper { public: // Getters and setters are present! private: int i; std::map<int, boost::interprocess::managed_shared_memory> shm; } int main() { boost::interprocess::managed_shared_memory shmInfo(boost::interprocess::open_or_create, "Test", 1024); boost::interprocess::map<int, Helper> myMap = shmInfo.construct< boost::interprocess::map<int, Helper> >("Memory"); } myMap (which is a map of int and Helper ) is constructed on the shared_memory. In turn, I

问题 This question already has answers here : POSIX shared memory and semaphores permissions set incorrectly by open calls (2 answers) Closed 2 years ago . I am creating my shared memory using the below, trying either to open or create and setting unrestricted permissions. void createMemory(const int numBytes) { permissions perm; perm.set_unrestricted(); segment.reset(new managed_shared_memory(open_or_create, memory_name, numBytes, 0, perm)); // Exception throw on this line mutex.reset(new named

问题 I have a multithreaded server application that needs mutex locks over some shared memory. The shared memory are basically sTL maps etc. Much of the time I'm just reading from the map. But, I also need to occasionally add to it. e.g. typedef std::map MessageMap; MessageMap msgmap; boost:shared_mutex access_; void ProcessMessage(Message* message) { // Access message... read some stuff from it message->... UUID id = message->GetSessionID(); // Need to obtain a lock here. (shared lock? multiple

问题 I have a multithreaded server application that needs mutex locks over some shared memory. The shared memory are basically sTL maps etc. Much of the time I'm just reading from the map. But, I also need to occasionally add to it. e.g. typedef std::map MessageMap; MessageMap msgmap; boost:shared_mutex access_; void ProcessMessage(Message* message) { // Access message... read some stuff from it message->... UUID id = message->GetSessionID(); // Need to obtain a lock here. (shared lock? multiple