Here are a few title options, keeping in mind the question format and relevance to the content: Option 1 (Focus on the problem): * Why is `delete buf` Incorrect When Using Placement New? Option 2 (

Placement New and Delete: Proper Memory Deallocation

When allocating memory with both the "placement new" operator (new (mem) syntax) and the standard new operator, it is crucial to use the correct method to release that memory.

Consider the following code snippet:

<code class="cpp">const char* charString = "Hello, World";
void *mem = ::operator new(sizeof(Buffer) + strlen(charString) + 1);
Buffer* buf = new(mem) Buffer(strlen(charString));</code>

To properly deallocate the allocated memory, you should call:

<code class="cpp">buf->~Buffer();
::operator delete(mem);</code>

This is because:

• Calling the Destructor: buf->~Buffer() explicitly calls the destructor of the Buffer object, which is necessary to release any resources held by the object.
• Calling the "Placement Delete" Function: ::operator delete(mem) releases the memory allocated by the placement new operator (new (mem)). Remember that if you use the "placement new" operator, you must also use the "placement delete" function to free the memory.

Incorrect Approaches:

Approach 1:

<code class="cpp">delete (char*)buf;</code>

This approach is incorrect because it attempts to delete the buffer as if it were a char* pointer. However, the memory was allocated with placement new, so you must use operator delete instead.

Approach 2:

<code class="cpp">delete buf;</code>

This approach is also incorrect because it fails to manually invoke the destructor of the Buffer object. As a result, any resources acquired by the object may not be released, potentially leading to memory leaks or other issues.

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