How can I disable all warnings for a single file with Clang 3.8?

Question

I'm using Clang 3.8 to compile one file that comes from a different source in a project. This is a temporary crutch, as this file is an addition to a library that I also use, and the code it has will be part of that library's next release. However, these people develop with less stringent warning flags than I do.

I'm not interested in these warnings as they're benign, I don't maintain that file, and it'll go away within a few months. Of course, I can selectively remove a warning or two, but I think that it makes more sense in this case to disable all and every warnings that it generates because I could change the warning settings of my project later and more occurrences could come out of it.

I've tried #pragma clang diagnostic ignored "-Weverything", but Clang warns that -Weverything is an unknown warning group.

How can I ask Clang to not generate any warnings for that file?

Answer 1

Indeed, the "-Weverything" is not a group of warnings, but just a special option passed to the compiler. Here is code that handles this case: lib/Basic/Warnings.cpp:118

You still can compile your problematic source file using slightly different rules/flags as you use for others sources:

clang -Wno-everything foo.c

However, I'd recommend to disable each warning explicitly using #pragma.

In case you disable all warnings, and then upgrade your compiler, then you may miss some new warnings, which could be important (e.g. undefined behaviour checks, security checks, etc).

Also, imagine what happens if the file is not gone after three months, but stays in the project forever.