-x <language> flag gets inserted in the end.

[mcourteaux]

Zig Version

0.14.0-dev.2802

Steps to Reproduce and Observed Behavior

In the spirit of using zig as a drop-in compiler, I bumped into the issue that some C++ code from a third-party library #includes an Objective C header. Their build system simply adds -x objective-c++ to that file, but trying to do the same from build.zig fails, because the compilation flag goes in the end, which is a no-op. The flag should go in front of the files that need to be impacted.

Currently zig solely determines the language based on the extension, with no way to override it from build.zig.
A low-effort hack might be to simply detect the "-x" string being passed to the CSourceFile.flags and instead put that flag in the front?

I read in #13544 that @motiejus worked on something related to this, and did explicitly not include supporting specifying -x <language> from build.zig, because there was doubt whether that was a good idea or not.

Expected Behavior

const lib = b.addSharedLibrary(...);
lib.addCSourceFile(.{
   .file = "some_file.cpp",
   .flags = &.{"-x", "objective-c++"},
});

works and compiles this as Objective-C++.

[alexrp]

Isn't this addressed by #20687?

[mcourteaux]

Isn't this addressed by #20687?

Lol! Yesterday?! 😲 😝 I'll try it and close this in a couple minutes then. I hope it's in the nightly.

[mcourteaux]

Not yet in the nightly build. I'll wait until tomorrow then to try to compile this. Thanks for the extremely quick reply!

[mcourteaux]

Well, instead of waiting for tomorrow's nightly...,

git apply <(curl https://patch-diff.githubusercontent.com/raw/ziglang/zig/pull/20687.patch)

did the trick. Really neat feature on Github. The patch works. Thanks a lot!