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clarify behavior of __ptr32/__ptr64 example #5860

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clarify behavior of __ptr32/__ptr64 example #5860

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2 changes: 1 addition & 1 deletion docs/cpp/ptr32-ptr64.md
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Expand Up @@ -28,7 +28,7 @@ For compatibility with previous versions, **_ptr32** and **_ptr64** are synonyms

## Example

The following example shows how to declare and allocate pointers with the **`__ptr32`** and **`__ptr64`** keywords.
The following example shows how to declare and allocate pointers with the **`__ptr32`** and **`__ptr64`** keywords. This code will crash when compiled for 64-bit due to the pointer from `malloc` being truncated to 32-bit. Since 32-bit pointers can be represented in 64-bit, when compiled for 32-bit this code does not necessarily crash.
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Copilot AI Dec 8, 2025

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The phrase "This code will crash" uses future tense ("will"). According to the Microsoft Writing Style Guide, use present tense verbs instead of future tense. Consider: "This code crashes when compiled for 64-bit..."

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According to the Microsoft Writing Style Guide, break up long sentences for better readability. This sentence contains multiple independent clauses. Consider splitting into separate sentences:

"This code crashes when compiled for 64-bit due to the pointer from malloc being truncated to 32-bit. When compiled for 32-bit, this code does not necessarily crash because 32-bit pointers can be represented in 64-bit."

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The phrasing "when compiled for 32-bit this code does not necessarily crash" is ambiguous. The statement "32-bit pointers can be represented in 64-bit" appears to be explaining the wrong scenario - it should explain why 64-bit pointers can fit in 32-bit address space on 32-bit systems (they can't exceed 32-bit addresses). Consider clarifying the technical explanation:

"When compiled for 32-bit, this code does not crash because the __ptr64 pointer is truncated to 32-bit, which is sufficient for the 32-bit address space."

Suggested change
The following example shows how to declare and allocate pointers with the **`__ptr32`** and **`__ptr64`** keywords. This code will crash when compiled for 64-bit due to the pointer from `malloc` being truncated to 32-bit. Since 32-bit pointers can be represented in 64-bit, when compiled for 32-bit this code does not necessarily crash.
The following example shows how to declare and allocate pointers with the **`__ptr32`** and **`__ptr64`** keywords. This code will crash when compiled for 64-bit because the pointer from `malloc` is truncated to 32 bits. When compiled for 32-bit, this code does not crash because the `__ptr64` pointer is truncated to 32 bits, which is sufficient for the 32-bit address space.

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```cpp
#include <cstdlib>
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