Skip to content
Branch: master
Find file Copy path
Find file Copy path
1 contributor

Users who have contributed to this file

106 lines (77 sloc) 3.8 KB

Contributing to ccache

Want to contribute to ccache? Awesome!

Asking a question?

It's OK to ask questions in the issue tracker for now.

However, please consider posting your question to the mailing list instead, since you are more likely to get an answer there.

Reporting an issue?

Please include at least the following information in your bug report:

  1. Which version of ccache you use.
  2. Which compiler you use, if applicable.
  3. Which operating system you use, if applicable.
  4. The problematic behavior you experienced (actual behavior).
  5. How you would like ccache to behave instead (expected behavior).
  6. Steps to reproduce the problematic behavior.

Also, consider reading Effective Ways to Get Help from Maintainers.

Contributing code?

The preferred way is to create one or several pull request with your proposal(s) on GitHub.

If you plan to implement major changes it is wise to open an issue on GitHub (or send a mail to the mailing list) asking for comments on your plans before doing the bulk of the work. That way you can avoid potentially wasting time on doing something that might not end up being accepted.

How to write commit messages

  • Write a summary (short description) on the first line.
  • Start the summary with a capital letter. Optional: prefix the short description with a context followed by a colon.
  • The summary should be in imperative mood (see examples below).
  • The summary should not end with a period. It's a title and titles don't end with a period.
  • If a longer description is wanted, add a second line empty and write the longer description on line three and below.
  • Keep lines in the message at most 72 characters wide.

Example 1:

Hash a delimiter string between parts to separate them

Previously, "gcc -I-O2 -c file.c" and "gcc -I -O2 -c file.c" would hash
to the same sum.

Example 2:

win32: Add a space between filename and error string in x_fmmap()

See also:

Code style


  • Use tabs for indenting and spaces for aligning C code.
  • Use 4 spaces for indenting other code (and spaces for aligning).
  • Put the opening curly brace on a new line when defining a function, otherwise at the end of the same line.
  • Put no space between function name and the following parenthesis.
  • Put one space between if/switch/for/while/do and opening curly brace.
  • Always use curly braces around if/for/while/do bodies, even if they only contain one statement.
  • If possible, keep lines at most 80 character wide for a 2 character tab width.
  • Use only lowercase names for functions and variables.
  • Use only uppercase names for enum items and (with some exceptions) macros.
  • Don't use typedefs for structs and enums.
  • Use //-style comments.

Tip: Install the tool uncrustify and then run "make uncrustify" to fix up source code formatting.


  • Declare variables as late as convenient, not necessarily at the beginning of the scope.
  • Use NULL to initialize null pointers.
  • Don't use NULL when comparing pointers.
  • Use format(), x_malloc() and friends instead of checking for memory allocation failure explicitly.
  • Use str_eq() instead of strcmp() when testing for string (in)equality.
  • Consider using str_startswith() instead of strncmp().
  • Use bool, true and false for boolean values.
  • Use tmp_unlink() or x_unlink() instead of unlink().
  • Use x_rename() instead of rename().


  • Strive to minimize use of global variables.
  • Write test cases for new code.
You can’t perform that action at this time.