8337784: Fix simple -Wzero-as-null-pointer-constant warnings in linux/posix code

[kimbarrett]

Please review this trivial change that replaces some uses of literal 0 as a
null pointer constant in linux/posix code to instead use nullptr.

Testing: mach5 tier1

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8337784: Fix simple -Wzero-as-null-pointer-constant warnings in linux/posix code (Enhancement - P4)

Reviewers

• Stefan Karlsson (@stefank - Reviewer)
• Aleksey Shipilev (@shipilev - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/20452/head:pull/20452
$ git checkout pull/20452

Update a local copy of the PR:
$ git checkout pull/20452
$ git pull https://git.openjdk.org/jdk.git pull/20452/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 20452

View PR using the GUI difftool:
$ git pr show -t 20452

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/20452.diff

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[bridgekeeper]

👋 Welcome back kbarrett! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@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:

8337784: Fix simple -Wzero-as-null-pointer-constant warnings in linux/posix code

Reviewed-by: stefank, shade

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 8 new commits pushed to the master branch:

• c095c0e: 8336489: Track scoped accesses in JVMCI compiled code
• 7e925d7: 8337283: configure.log is truncated when build dir is on different filesystem
• 2e093b0: 8337779: test/jdk/jdk/jfr/jvm/TestHiddenWait.java is a bit fragile
• d3e7b0c: 8336462: ConcurrentSkipListSet Javadoc incorrectly warns about size method complexity
• be34730: 8335257: Refactor code to create Initialized Assertion Predicates into separate class
• fbe8a81: 8333144: docker tests do not work when ubsan is configured
• dabdae6: 8334599: Improve code from JDK-8302671
• 8bd3cd5: 8337716: ByteBuffer hashCode implementations are inconsistent

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[openjdk]

@kimbarrett The following label will be automatically applied to this pull request:

• hotspot-runtime

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[mlbridge]

Webrevs

• 00: Full (62cdefcf)

[shipilev]

Looks fine.

[kimbarrett]

Thanks for reviews @stefank and @shipilev .

[kimbarrett]

/integrate

[openjdk]

Going to push as commit 807186f.
Since your change was applied there have been 12 commits pushed to the master branch:

• e68df52: 8337054: JDK 23 RDP2 L10n resource files update
• 9856216: 8336928: GHA: Bundle artifacts removal broken
• 219e1eb: 8337712: Wrong javadoc in java.util.Date#toString(): "61" and right parenthesis
• 97afbd9: 8336410: runtime/NMT/TotalMallocMmapDiffTest.java Total malloc diff is incorrect. Expected malloc diff range
• c095c0e: 8336489: Track scoped accesses in JVMCI compiled code
• 7e925d7: 8337283: configure.log is truncated when build dir is on different filesystem
• 2e093b0: 8337779: test/jdk/jdk/jfr/jvm/TestHiddenWait.java is a bit fragile
• d3e7b0c: 8336462: ConcurrentSkipListSet Javadoc incorrectly warns about size method complexity
• be34730: 8335257: Refactor code to create Initialized Assertion Predicates into separate class
• fbe8a81: 8333144: docker tests do not work when ubsan is configured
• ... and 2 more: https://git.openjdk.org/jdk/compare/367e0a65561f95aad61b40930d5f46843fee3444...master

Your commit was automatically rebased without conflicts.

[openjdk]

@kimbarrett Pushed as commit 807186f.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.