Indenting preprocessor directives with clang-format

Question

I am working on a c++ project where I am using a lot of #pragma omp. I use the wonderful clang-format for tidiness but it always deletes the indentation for all preprocessor directives. Is there a way to change that behavior? Or is there another formatting tool that is more recommendable? Or should I avoid using these tools at all?

Answer 1

As of version 6.0, the option IndentPPDirectives can be used. Usage is described in this review.

Using IndentPPDirectives: None results in:

#if FOO #if BAR #include <foo> #endif #endif 

While IndentPPDirectives: AfterHash gives:

#if FOO #  if BAR #    include <foo> #  endif #endif 

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Edit: see @Gabriel Staples' answer for details on the BeforeHash option introduced in clang-format version 9.

Answer 2

You might want to just patch it yourself and make a pull request.

It's not that hard, I made a similarly mundane pull request once. The clang-format code is pretty tidy. Clang-format already handles code comments in the way that you want, aligning them to the surrounding code (at least it has an option to enable this) so making a patch to treat certain PP directives the same way should be straightforward.

Alternatively, you can just write the patch yourself and compile clang yourself from source with the extra option, for use in your project. I also did this before I decided to send them the patch.

It seriously took me only a few hours to figure out how to do this, their code is much cleaner than the code of many other open source projects.