提升ipc new和delete操作符
boost ipc new and delete operators
我在boost ipc(进程间通信)中看到了一个例子
#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 exit
struct 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 size
shm.truncate(sizeof(trace_queue));
//Map the whole shared memory in this process
mapped_region region
(shm //What to map
,read_write //Map it as read-write
);
//Get the address of the mapped region
void * addr = region.get_address();
//Construct the shared structure in memory
trace_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");
else
std::sprintf(data->items, "%s_%d", "my_trace", i);
//Notify to the other process that there is a message
data->cond_empty.notify_one();
//Mark message buffer as full
data->message_in = true;
}
}
catch(interprocess_exception &ex){
std::cout << ex.what() << std::endl;
return 1;
}
return 0;
}
示例中没有delete
运算符。可能在内存区域中使用了新的运算符,它不能与delete
运算符一起使用。如果我需要调用析构函数,我应该直接调用:
data->~trace_queue();
我说得对吗?
然而,我建议使用具有find<T>
、find_or_construct<T>
或construct<T>
的managed_shared_memory
,让你的生活更轻松。
在进行此操作时,如果需要存储许多相同类型的对象,请考虑使用该类型的std::vector
(或boost::container::vector
)和boost::interprocess::allocator
。
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