# Re: Conversion of 'git submodule' to C: need some help

1 messages from 2020-02-09 to 2020-02-09. Participants: Abhishek Kumar.
Thread: https://gitlist.dev/t/52767

## Abhishek Kumar, 2020-02-09 15:00

Subject: Re: Conversion of 'git submodule' to C: need some help
Message-ID: <CAHk66fte4Rv199jJ8xgrpkzyonyXdhtYzn4fPA7mWPrKA9v2zA@mail.gmail.com>
URL: https://gitlist.dev/e/CAHk66fte4Rv199jJ8xgrpkzyonyXdhtYzn4fPA7mWPrKA9v2zA%40mail.gmail.com

```
Greetings Shourya

> 1. What exactly are we aiming in [3]? To replace the function completely
> or to just add some 'repo_submodule_init' functionality?

We are aiming to convert calls to use `repo_submodule_init` instead
and remove this function.

If they differ in functionality, implement any changes to
`repo_submodule_init` such that code that already uses it runs without
any modifications.

> 2. Something I inferred was that functions with names of the pattern 'strbuf_git_*'
> are trying to 'create a path' (are they physically creating the path or just instructing git about them?)

`strbuf_git_*` construct a path to the git directory and append it to
the string buffer passed. They are not physically creating folders,
just creating a string variable that stores the path.
If anything, it returns -1 when the git directory does not exist already. [1]

> while functions of the pattern 'git_*' are trying to check some conditions denoted
> by their function names(for instance  'git_config_rename_section_in_file')?
> Is this inference correct to some extent?

While I cannot talk about whether your inference is correct,
`git_config_rename_section_in_file` does not **just** check the
condition.

In the case of `remove_path_from_submodules` (where I am guessing you
had this doubt), it removes the section from `.gitmodules` and returns
a negative value on failure [2]

It's a common idiom in C - Functions with intended side effects return
non zero (usually negative) values on failure and zero otherwise. [3]

3. Not sure what you mean. Do elaborate.

4. Yes! Everyone has to begin at some point and learn. Feel free to
ask more questions when in doubt.

Regards
Abhishek

[1]: https://github.com/git/git/blob/de93cc14ab7e8db7645d8dbe4fd2603f76d5851f/submodule.c#L2257
[2]: https://github.com/git/git/blob/de93cc14ab7e8db7645d8dbe4fd2603f76d5851f/config.c#L3051
[3]: https://wiki.c2.com/?CeeIdioms

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