[libc][c11] implement ctime

[nickdesaulniers]

@alanzhao1 points out that quake3 uses man 3 ctime. We already support asctime; my guess is that ctime would be similar to implement in terms of LIBC_NAMESPACE::time_utils but for a different input parameter type.

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor has already been assigned to this issue. If you believe that no one is actually working on it despite an assignment, ping the person. After one week without a response, the assignee may be changed.
2. In the comments of this issue, request for it to be assigned to you, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: Nick Desaulniers (nickdesaulniers)

@alanzhao1 points out that quake3 uses `man 3 ctime`. We already support `asctime`; my guess is that `ctime` would be similar to implement in terms of `LIBC_NAMESPACE::time_utils` but for a different input parameter type.

[llvmbot]

@llvm/issue-subscribers-libc

Author: Nick Desaulniers (nickdesaulniers)

@alanzhao1 points out that quake3 uses `man 3 ctime`. We already support `asctime`; my guess is that `ctime` would be similar to implement in terms of `LIBC_NAMESPACE::time_utils` but for a different input parameter type.

[llvmbot]

@llvm/issue-subscribers-c11

Author: Nick Desaulniers (nickdesaulniers)

@alanzhao1 points out that quake3 uses `man 3 ctime`. We already support `asctime`; my guess is that `ctime` would be similar to implement in terms of `LIBC_NAMESPACE::time_utils` but for a different input parameter type.

[aniplcc]

I'd like to implement this.

[nickdesaulniers]

Thanks @aniplcc !

[SharmaRithik]

Can I request any update on this issue?

[aniplcc]

I'm working on it, (a bit busy with exams rn)
It actually involves two more dependencies,
man 3 tzset
and
man 3 localtime
to be implemented as well.

[SharmaRithik]

Thanks for the update. Sounds good! Let me know if you need any help or reviews.

[tszhin-swe]

Hello @aniplcc, are you still working on this? If not, I would be happy to take over.

[SharmaRithik]

This has been up for a while. Thanks @tszhin-swe, please ping here for any questions!