Persistent_ptr atomic allocation functions for objects. More...

#include <libpmemobj++/allocation_flag.hpp>
#include <libpmemobj++/detail/check_persistent_ptr_array.hpp>
#include <libpmemobj++/detail/common.hpp>
#include <libpmemobj++/detail/make_atomic_impl.hpp>
#include <libpmemobj++/detail/variadic.hpp>
#include <libpmemobj++/make_persistent_array_atomic.hpp>
#include <libpmemobj++/pexceptions.hpp>
#include <libpmemobj++/pool.hpp>
#include <libpmemobj/atomic_base.h>
#include <tuple>

Namespaces
	pmem
	A persistent version of concurrent hash map implementation Ref: https://arxiv.org/abs/1509.02235.

Functions
template<typename T , typename... Args>
void	pmem::obj::make_persistent_atomic (pool_base &pool, typename detail::pp_if_not_array< T >::type &ptr, allocation_flag_atomic flag, Args &&... args)
	Atomically allocate and construct an object. More...

template<typename T , typename... Args>
std::enable_if<!detail::is_first_arg_same< allocation_flag_atomic, Args... >::value >::type	pmem::obj::make_persistent_atomic (pool_base &pool, typename detail::pp_if_not_array< T >::type &ptr, Args &&... args)
	Atomically allocate and construct an object. More...

template<typename T >
void	pmem::obj::delete_persistent_atomic (typename detail::pp_if_not_array< T >::type &ptr) noexcept
	Atomically deallocate an object. More...

Detailed Description

Persistent_ptr atomic allocation functions for objects.

The typical usage examples would be:

#include <fcntl.h>
#include <libpmemobj++/make_persistent_atomic.hpp>
#include <libpmemobj++/p.hpp>
#include <libpmemobj++/persistent_ptr.hpp>
#include <libpmemobj++/pool.hpp>
#include <libpmemobj++/transaction.hpp>
using namespace pmem::obj;
void
make_persistent_atomic_example()
{
    struct compound_type {
        compound_type(int val, double dval)
            : some_variable(val), some_other_variable(dval)
        {
        }
        void
        set_some_variable(int val)
        {
            some_variable = val;
        }
        p<int> some_variable;
        p<double> some_other_variable;
    };
    // pool root structure
    struct root {
        persistent_ptr<compound_type> comp; //
    };
    // create a pmemobj pool
    auto pop = pool<root>::create("poolfile", "layout", PMEMOBJ_MIN_POOL);
    auto proot = pop.root();
    // typical usage schemes
    // atomic allocation and construction with arguments passing
    make_persistent_atomic<compound_type>(pop, proot->comp, 1, 2.0);
    // atomic object deallocation, ~compound_type() is not called
    delete_persistent<compound_type>(proot->comp);
    // error prone cases
    transaction::run(pop, [&] {
        // possible invalid state in case of transaction abort
        make_persistent_atomic<compound_type>(pop, proot->comp, 1, 1.3);
        delete_persistent_atomic<compound_type>(proot->comp);
    });
}

Function Documentation

◆ delete_persistent_atomic()

template<typename T >

void pmem::obj::delete_persistent_atomic ( typename detail::pp_if_not_array< T >::type & ptr )

noexcept

Atomically deallocate an object.

There is no way to atomically destroy an object. Any object specific cleanup must be performed elsewhere. Do NOT use this inside transactions, as it might lead to undefined behavior in the presence of transaction aborts.

param[in,out] ptr the persistent_ptr whose pointee is to be deallocated.

◆ make_persistent_atomic() [1/2]

template<typename T , typename... Args>

void pmem::obj::make_persistent_atomic	(	pool_base &	pool,
		typename detail::pp_if_not_array< T >::type &	ptr,
		allocation_flag_atomic	flag,
		Args &&...	args
	)

Atomically allocate and construct an object.

Constructor parameters are passed through variadic parameters. Do NOT use this inside transactions, as it might lead to undefined behavior in the presence of transaction aborts.

Parameters

[in,out]	pool	the pool from which the object will be allocated.
[in,out]	ptr	the persistent pointer to which the allocation will take place.
[in]	flag	affects behaviour of allocator
[in]	args	variadic function parameter containing all parameters passed to the objects constructor.

Exceptions

std::bad_alloc on allocation failure.

◆ make_persistent_atomic() [2/2]