8327173: HotSpot Style Guide needs update regarding nullptr vs NULL #18101
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doc/hotspot-style.md
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| ([n2431](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2431.pdf)) | ||
| to `NULL`. Don't use (constexpr or literal) 0 for pointers. | ||
| rather than `NULL`. Don't use (constant expression or literal) 0 for pointers. |
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Should there be any discussion here of why we want to avoid NULL? Specifically the varying
definitions and the pitfalls of NULL in varargs context. Also template and overload issues.
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I think it would be enough to write 1..2 sentences about this, and then defer to N2431 already linked here for more details.
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Good point. I decided just referring to the paper for rationale is sufficient.
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doc/hotspot-style.md
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| ([n2431](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2431.pdf)) | ||
| to `NULL`. Don't use (constexpr or literal) 0 for pointers. | ||
| rather than `NULL`. Don't use (constant expression or literal) 0 for pointers. |
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I think it would be enough to write 1..2 sentences about this, and then defer to N2431 already linked here for more details.
doc/hotspot-style.md
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| The C++11 definition of _null pointer constant_ included integral constant | ||
| expressions with value zero. C++14 replaced that with integer literals with | ||
| value zero. Some compilers continue to treat a zero-valued integral constant | ||
| expressions as a _null pointer constant_ even in C++14 mode. |
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It is not very clear why should this concern any Hotspot developers?
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If one is familiar with C++14 (or later) or were to look up null pointer
constant in the C++14 standard, one might wonder why this style guide
admonishes against using non-literal constant expressions for such. But I've
rewritten the part about 0 as a pointer to (I think) make things clearer.
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@kimbarrett This change now passes all automated pre-integration checks. ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details. After integration, the commit message for the final commit will be: You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed. At the time when this comment was updated there had been no new commits pushed to the ➡️ To integrate this PR with the above commit message to the |
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I just discovered gcc |
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Thanks for reviews @vnkozlov , @kimbarrett , and @dholmes-ora . |
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/integrate |
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Going to push as commit 3d37b28. |
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@kimbarrett Pushed as commit 3d37b28. 💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored. |
Please review this change to update the HotSpot Style Guide's discussion of
nullptr and its use.
I suggest this is an editorial rather than substantive change to the style
guide. As such, the normal HotSpot PR process can be used for this change.
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