#include <boost/interprocess/sync/interprocess_mutex.hpp>
#include <boost/interprocess/sync/interprocess_condition.hpp>struct trace_queue
{enum { LineSize = 100 };trace_queue(): message_in(false){}//Mutex to protect access to the queueboost::interprocess::interprocess_mutex mutex;//Condition to wait when the queue is emptyboost::interprocess::interprocess_condition cond_empty;//Condition to wait when the queue is fullboost::interprocess::interprocess_condition cond_full;//Items to fillchar items[LineSize];//Is there any messagebool message_in;
};
#include <boost/interprocess/shared_memory_object.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#include <iostream>
#include <cstdio>
#include "doc_anonymous_condition_shared_data.hpp"using namespace boost::interprocess;int main ()
{//Erase previous shared memory and schedule erasure on exitstruct shm_remove{shm_remove() { shared_memory_object::remove("MySharedMemory"); }~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }} remover;//Create a shared memory object.shared_memory_object shm(create_only //only create,"MySharedMemory" //name,read_write //read-write mode);try{//Set sizeshm.truncate(sizeof(trace_queue));//Map the whole shared memory in this processmapped_region region(shm //What to map,read_write //Map it as read-write);//Get the address of the mapped regionvoid * addr = region.get_address();//Construct the shared structure in memorytrace_queue * data = new (addr) trace_queue;const int NumMsg = 100;for(int i = 0; i < NumMsg; ++i){scoped_lock<interprocess_mutex> lock(data->mutex);if(data->message_in){data->cond_full.wait(lock);}if(i == (NumMsg-1))std::sprintf(data->items, "%s", "last message");elsestd::sprintf(data->items, "%s_%d", "my_trace", i);//Notify to the other process that there is a messagedata->cond_empty.notify_one();//Mark message buffer as fulldata->message_in = true;}}catch(interprocess_exception &ex){std::cout << ex.what() << std::endl;return 1;}return 0;
}
第二個過程打開共享內存，打印每一條消息，直到收到 "最后一條消息 "消息。
#include <boost/interprocess/shared_memory_object.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#include <iostream>
#include <cstdio>
#include "doc_anonymous_condition_shared_data.hpp"using namespace boost::interprocess;int main ()
{//Erase previous shared memory and schedule erasure on exitstruct shm_remove{shm_remove() { shared_memory_object::remove("MySharedMemory"); }~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }} remover;//Create a shared memory object.shared_memory_object shm(create_only //only create,"MySharedMemory" //name,read_write //read-write mode);try{//Set sizeshm.truncate(sizeof(trace_queue));//Map the whole shared memory in this processmapped_region region(shm //What to map,read_write //Map it as read-write);//Get the address of the mapped regionvoid * addr = region.get_address();//Construct the shared structure in memorytrace_queue * data = new (addr) trace_queue;const int NumMsg = 100;for(int i = 0; i < NumMsg; ++i){scoped_lock<interprocess_mutex> lock(data->mutex);if(data->message_in){data->cond_full.wait(lock);}if(i == (NumMsg-1))std::sprintf(data->items, "%s", "last message");elsestd::sprintf(data->items, "%s_%d", "my_trace", i);//Notify to the other process that there is a messagedata->cond_empty.notify_one();//Mark message buffer as fulldata->message_in = true;}}catch(interprocess_exception &ex){std::cout << ex.what() << std::endl;return 1;}return 0;
}
通過條件變量，一個進程如果不能繼續工作就可以阻塞，當滿足繼續工作的條件時，另一個進程可以喚醒它。
#include <boost/interprocess/shared_memory_object.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#include <iostream>
#include <cstring>
#include "doc_anonymous_condition_shared_data.hpp"using namespace boost::interprocess;int main ()
{//Create a shared memory object.shared_memory_object shm(open_only //only create,"MySharedMemory" //name,read_write //read-write mode);try{//Map the whole shared memory in this processmapped_region region(shm //What to map,read_write //Map it as read-write);//Get the address of the mapped regionvoid * addr = region.get_address();//Obtain a pointer to the shared structuretrace_queue * data = static_cast<trace_queue*>(addr);//Print messages until the other process marks the endbool end_loop = false;do{scoped_lock<interprocess_mutex> lock(data->mutex);if(!data->message_in){data->cond_empty.wait(lock);}if(std::strcmp(data->items, "last message") == 0){end_loop = true;}else{//Print the messagestd::cout << data->items << std::endl;//Notify the other process that the buffer is emptydata->message_in = false;data->cond_full.notify_one();}}while(!end_loop);}catch(interprocess_exception &ex){std::cout << ex.what() << std::endl;return 1;}return 0;
}
