8378180: Compiling OpenJDK with C23 C-Compiler gives warning: initialization discards ‘const’ qualifier from pointer target type

[fthevenet]

Hi all,

This pull request contains a backport of commit 76a44b3e from the openjdk/jdk repository.

The commit being backported was authored by Jasmine Karthikeyan on 22 Apr 2026 and was reviewed by Daniel Jeliński and Alan Bateman.

This patch is needed in order to build jdk26u with more recent version of gcc (16.1.1+), as it fixes compiler warnings.
Backport is almost clean except for a conflicting copyright year in NetworkInterface.c.

Thanks!

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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
• JDK-8378180 needs maintainer approval

Issue

• JDK-8378180: Compiling OpenJDK with C23 C-Compiler gives warning: initialization discards ‘const’ qualifier from pointer target type (Enhancement - P3 - Requested)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk25u-dev.git pull/577/head:pull/577
$ git checkout pull/577

Update a local copy of the PR:
$ git checkout pull/577
$ git pull https://git.openjdk.org/jdk25u-dev.git pull/577/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 577

View PR using the GUI difftool:
$ git pr show -t 577

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Download this PR as a diff file:
https://git.openjdk.org/jdk25u-dev/pull/577.diff

Using Webrev

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[bridgekeeper]

👋 Welcome back fthevenet! A progress list of the required criteria for merging this PR into pr/576 will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 02: Full - Incremental (2110d471)
• 01: Full - Incremental (9c9733a4)
• 00: Full (9c9733a4)

[fthevenet]

/approval request I'd like to backport this to JDK 25.

Motivation: This patch is needed in order to build jdk26u with more recent version of gcc (16.1.1+), as it fixes compiler warnings.
Backport is almost clean except for a conflicting copyright year in NetworkInterface.c.

The change introduces no behaviour change and, I believe, is low risk.

I have verified that building jdk25u with this patch results in no warning when using gcc 16.1.1 on Fedora 44

[openjdk]

@fthevenet
8378180: The approval request has been created successfully.

[phohensee]

In NetworkInterface.c, you've imported a new macro CHECKED_MALLOC4, which isn't in the original commit.

[fthevenet]

In NetworkInterface.c, you've imported a new macro CHECKED_MALLOC4, which isn't in the original commit.

Yes, that indeed looks fishy. thanks for catching that.

[openjdk-notifier]

The parent pull request that this pull request depends on has now been integrated and the target branch of this pull request has been updated. This means that changes from the dependent pull request can start to show up as belonging to this pull request, which may be confusing for reviewers. To remedy this situation, simply merge the latest changes from the new target branch into this pull request by running commands similar to these in the local repository for your personal fork:

git checkout backport-fthevenet-76a44b3e-master
git fetch https://git.openjdk.org/jdk25u-dev.git master
git merge FETCH_HEAD
# if there are conflicts, follow the instructions given by git merge
git commit -m "Merge master"
git push

[fthevenet]

I had indeed missed that the changes to CHECKED_MALLOC4 were introduces by JDK-8362884.
Since this looks reasonable to backport as well, I believe the better thing to do is to port it to 25u first and then re-target this PR on top of it.

[GoeLin]

Hi @fthevenet, please resolve the conflicts.

[fthevenet]

Hi @GoeLin

Hi @fthevenet, please resolve the conflicts.

Done, but this cannot be integrated for the moment as this change incorrectly introduce code from a different change.

[...] changes to CHECKED_MALLOC4 were introduces by JDK-8362884.
Since this looks reasonable to backport as well, I believe the better thing to do is to port it to 25u first and then re-target this PR on top of it.

Do you confirm that this is the right approach?
Thanks.