Can I prevent clang-format from formatting some (generated) files? - clang-format

Question

Some of the C source files in my project are generated. They obviously are not formatted to the standard in the .clang-format file.
If I just clang-format or git clang-format that generate source is re-formatted causing unnecessary clutter in the commits.
Is there a way to specify that some files should be ignored by clang-format?

Answer 1

In the default implementation of the git clang-format there is no flag or something to ignore autogenerated files .
but it can be achieved by implementing a wrapper script ( I will show how to do that in bash) that will clean the files that you don't want to format and then using the git clang-format.
for example:
1.first of all lets say your generated files include a pattern for example auto_gen or generated .
2.define a regex exp for the auto generated patterns in our example
it can be : pattern_to_exclude_from_clang='.*auto_gen|.*generated'
3.define allfiles = git diff --name-only - this will give you all
the files that your commit change.
4.filter out generated files allfiles ( exclude generated files)
5.run git clang-format --diff -- ${wantedfiles[#]}
so the final script can be :
#!/bin/bash
pattern_to_exclude_from_clang='.*auto_gen|.*generated'
allfiles=`git diff --name-only`
files_array=($allfiles)
for i in "${!files_array[#]}":
do
if [[ "${files_array[$i]}" =~ $pattern_to_exclude_from_clang ]];then
printf "%s %s" "${files_array[$i]" "this file will be skipped by clang"
unset files_array[$i]
fi
done
git clang-format --diff -- ${allfiles[#]}