Style Guides

Coding Conventions

UnifyFS follows the Linux kernel coding style except that code is indented using four spaces per level instead of tabs. Please run make checkstyle to check your patch for style problems before submitting it for review.

Styling Code

The astyle tool can be used to apply much of the required code styling used in the project.

To apply style to the source file foo.c:
astyle --options=scripts/unifyfs.astyle foo.c

The unifyfs.astyle file specifies the options used for this project. For a full list of available astyle options, see

Verifying Style Checks

To check that uncommitted changes meet the coding style, use the following command:

git diff | ./scripts/


This command will only check specific changes and additions to files that are already tracked by git. Run the command git add -N [<untracked_file>...] first in order to style check new files as well.

Commit Message Format

Commit messages for new changes must meet the following guidelines:

  • In 50 characters or less, provide a summary of the change as the first line in the commit message.

  • A body which provides a description of the change. If necessary, please summarize important information such as why the proposed approach was chosen or a brief description of the bug you are resolving. Each line of the body must be 72 characters or less.

An example commit message for new changes is provided below.

Capitalized, short (50 chars or less) summary

More detailed explanatory text, if necessary.  Wrap it to about 72
characters or so.  In some contexts, the first line is treated as the
subject of an email and the rest of the text as the body.  The blank
line separating the summary from the body is critical (unless you omit
the body entirely); tools like rebase can get confused if you run the
two together.

Write your commit message in the imperative: "Fix bug" and not "Fixed bug"
or "Fixes bug."  This convention matches up with commit messages generated
by commands like git merge and git revert.

Further paragraphs come after blank lines.

- Bullet points are okay

- Typically a hyphen or asterisk is used for the bullet, followed by a
  single space, with blank lines in between, but conventions vary here

- Use a hanging indent