Support for .res and .rct files?

[rodrigocfd]

Visual Studio Resource Editor is capable of exporting self-contained .rct and .res files, which do not depend on Windows headers.

It seems that, in its current version, embed-resource can load only .rc files. It would add extra flexibility if .rct and .res files could be loaded too, maybe with other methods besides compile.

[nabijaczleweli]

Cool, how are they different (from the canonically-.rc source and one another) and how do you make them linkable?

[rodrigocfd]

The .rct format is some sort of self-contained file created in Visual Studio, called Native Resource Template. I really don't know anything about the binary format, so we can let it aside for now.

---

The .res format is the binary result of the .rc compilation produced by the RC tool, which is then passed to the linker. I presume embed_resource::compile (which takes an .rc file) compiles it into a .res, and then this .res is passed to the linker in some way.

If so, adding .res support would be a matter of adding a mid-step to embed_resource::compile. We would have something like embed_resource::embed, which would be called by compile. In a bird's-eye view, these would be the external functions:

// Same pub function we have today.
pub fn compile(rc_file: &str) {
    let res_file = internal_compilation_stuff(rc_file);
    embed(res_file);
}

// New public function.
pub fn embed(res_file: &str) {
    // embed into exe..
}

I also see the possibility of leaving compile the way it is, and simply add embed as a function calling the linker with the .res file.

[nabijaczleweli]

I mean, in that case, just link it directly, there's no processing that needs to be done except to print cargo:rustc-link-lib=dylib=your_artifact.res (or summat along those lines), which should be emitted by whatever's building it, right?

[rodrigocfd]

I'm unaware of such option... where I can find documentation about it?

[nabijaczleweli]

(a) https://docs.microsoft.com/en-us/cpp/build/reference/dot-res-files-as-linker-input?view=msvc-160, (b) https://doc.rust-lang.org/cargo/reference/build-scripts.html

[rodrigocfd]

Thank you very much.

I made it work, but I'm having a problem. The tool is always appending a .lib extension to my .res file, so the build fails because the file is never found. I manually renamed my stuff.res to stuff.res.lib... and then it finally worked.

Do you know any way to make it accept the .res extension?

[nabijaczleweli]

No idea; if you had direct access to the linker cmdline you might be able to spec just suff.res instead of -lstuff.res (or which-ever format LINK.EXE supports), but I don't think that's possible with Cargo control lines.

[rodrigocfd]

Do you know where I can open an issue about this Cargo behavior?

[nabijaczleweli]

https://github.com/rust-lang/cargo probably

[rodrigocfd]

Thank you very much. I opened an issue here.