unique_ptr::release
將傳回已儲存指標的擁有權釋放給呼叫者，並將已儲存的指標值設為 nullptr。
pointer release();
屬性值/傳回值
傳回已儲存的指標。
備註
使用 release 接管 unique_ptr 所儲存的原始指標之擁有權。 呼叫端會負責刪除傳回的指標。 unique-ptr 已設為空白的預設建構狀態。 呼叫 release 之後，您可以將相容類型的另一個指標指派至 unique_ptr。
範例
此範例顯示釋放呼叫者為何需負責傳回的物件：
// stl_release_unique.cpp
// Compile by using: cl /W4 /EHsc stl_release_unique.cpp
#include <iostream>
#include <memory>
struct Sample {
int content_;
Sample(int content) : content_(content) {
std::cout << "Constructing Sample(" << content_ << ")" << std::endl;
}
~Sample() {
std::cout << "Deleting Sample(" << content_ << ")" << std::endl;
}
};
void ReleaseUniquePointer() {
// Use make_unique function when possible.
auto up1 = std::make_unique<Sample>(3);
auto up2 = std::make_unique<Sample>(42);
// Take over ownership from the unique_ptr up2 by using release
auto ptr = up2.release();
if (up2) {
// This statement does not execute, because up2 is empty.
std::cout << "up2 is not empty." << std::endl;
}
// We are now responsible for deletion of ptr.
delete ptr;
// up1 deletes its stored pointer when it goes out of scope.
}
int main() {
ReleaseUniquePointer();
}
電腦輸出：
需求
標頭： <memory>
命名空間: std