How to use the smart pointer shared_ptr of Central11
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Shared_prt itself is a class, so its initialization is actually a call to the constructor of the shared_ptr class. By analyzing the constructor of shared_ptr, we can accurately grasp the initialization method of shared_ptr.
Default constructor
Function prototype:
Constexpr shared_ptr () noexcept
Description:
Declare an empty shared_ptr.
Code example:
Constructed from null pointers
Function prototype:
Constexpr shared_ptr (nullptr_t)
Description:
The shared_ptr is constructed with a null pointer, and the action default constructor acts the same.
Code example:
Constructed by pointers
Function prototype:
Explicit shared_ptr (U* p)
Description:
Construct shared_ptr based on existing pointers.
Code example:
Matters needing attention
Both of the methods shown in the example are legal, but in the second case it should be understood that once the share_ptr is constructed, it indicates that the memory management of the string object pointed to by s has been handed over to ps1 management and should no longer be accessed through s (at least very carefully).
The second way should be avoided as much as possible.
Copy construction
Function prototype:
Shared_ptr (const shared_ptr& x) noexcept
Description:
Create a new shared_ptr from an existing share_ptr. In the meantime, application counts are automatically maintained.
Code example:
Program output:
After the copy constructor is executed, the reference count increases and two pointers point to the same object.
Mobile structure
Function prototype:
Shared_ptr (shared_ptr&& x) noexcept
Description:
Create a new shared_ptr from an existing share_ptr. Shared_pt, as a parameter, also releases administrative rights to memory, and the reference count remains unchanged after the entire construction process.
Code example:
Program output:
Memory management has been transferred from ps to ps1.
Modifier description
Explicit: ensures that the constructor will not be called implicitly
Noexcept: this function does not throw an exception
Constexpr: this function can be evaluated during compilation
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