Clang-Format: How to specify a custom format options file?

Question

I'm trying to configure a custom style options file for clang-format v6.0.0 running on Windows 10 Pro 64-bit. I started out by generating an options file based upon the llvm style using the following command line, which worked fine:

clang-format -style=llvm -dump-config > .clang-format

The documentation for clang-format states the following: "When the desired code formatting style is different from the available options, the style can be customized using the -style="{key: value, ...}" option or by putting your style configuration in the .clang-format or _clang-format file in your project’s directory and using clang-format -style=file."

So just as a test I used the unchanged .clang-format file I generated above and used the following command line:

clang-format -style=.clang-format Test.c

The result was a message that said

"Invalid value for -style"

I then changed the name of .clang-format to _clang-format and tried it again but the result was the same. So, my question is, "How do I specify a specific style options file?"

Answer 1

As you correctly discovered command is expecting the literal -style=file. For example clang-format.exe -i -style=file The -i option is to execute the changes in place. The -style=file is telling the program to look in the current directory for the configuration file named .clang-format or _clang-format Configuration options. If the config file is still not found the program will move up a directory and continue searching and so on. More command line documentation can be found here.