Heap allocation and uniqueness unique_ptr

Question

Raw pointers can point to objects allocated on the stack or on the heap.

Heap placement example:

// heap allocation
int* rawPtr = new int(100);
std::cout << *rawPtr << std::endl;      // 100

Stack distribution example:

int i = 100;
int* rawPtr = &i;
std::cout << *rawPtr << std::endl;      // 100

Heap allocation using the auto_ptr example:

int* rawPtr = new int(100);
std::unique_ptr<int> uPtr(rawPtr);
std::cout << *uPtr << std::endl;        // 100

Stack distribution using the auto_ptr example:

int i = 100;
int* rawPtr = &i;
std::unique_ptr<int> uPtr(rawPtr);      // runtime error

Are smart pointers used to point to dynamically created objects on the heap? For C ++ 11, should we continue to use raw pointers to point to allocated stack objects? Thank.

Answer 1

, new delete. , , .

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{
    char buf[32];
    auto erase_buf = [](char *p) { memset(p, 0, sizeof(buf)); };
    std::unique_ptr<char, decltype(erase_buf)> passwd(buf, erase_buf);

    get_password(passwd.get());
    check_password(passwd.get());
}
// The deleter will get called since passwd has gone out of scope.
// This will erase the memory in buf so that the password doesn't live
// on the stack any longer than it needs to.  This also works for
// exceptions!  Placing memset() at the end wouldn't catch that.

Answer 2

, delete , new.

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• (), - , .

, ( int):

auto uPtr = std::make_unique<int>(100);

uPtr , . int () delete ed .

new delete . make_unique make_shared, new .

Answer 3

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Answer 4

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, . , std::unique_ptr ( (3)/(4) ), , -, "deleter", . ( ).

++ 11 ? .

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Another place to use is when you implement a class that has a complex ownership template for protected / private members.

PS: Please forget aboutstd::auto_ptr ... pretending it never existed :-)