Cargo: warning: unused manifest key: build

[yugoja]

Hi,

I'm a beginner in rust trying to get WASM development set up using this article.

I am getting error: could not exec the linker emcc : No such file or directory when I do cargo build.

I referred this article where it shows how to define build and linker configs using .cargo/config.

So I added following blocks to my Cargo.toml and .cargo/config.toml:

[build]
target = "wasm32-unknown-emscripten"

[target.wasm32-unknown-emscripten]
linker = "/Users/yugoja/emsdk-portable/clang/fastcomp/build_incoming_64/bin"

Now when I run cargo build, I get following warnings:

warning: unused manifest key: build
warning: unused manifest key: target.wasm32-unknown-emscripten.linker

It seems cargo is not using my configs. How can I fix this?

[behnam]

@yugoja, you only need to add these fields to your Cargo config file, not the manifest file. Although they look similar, they have different functionalities.

Here's more: http://doc.crates.io/config.html

And, as a side note: you can take these kinds of help wanted questions to the Rust Users Forum: https://users.rust-lang.org/. Filing issues here in repo is best when you find something wrong with Cargo code or documentations. If none of those is a matter here, we can close this issue. :)

[behnam]

Just to make it clear: you've added them to the config, which is fine and what you need. But, you should not add those to your manifest file, and this is why you get the warnings.

[yugoja]

Hi @behnam
Thank you for your reply.
From now on I'll use Rust Users forum for my help questions.

But for this current issue, I removed the build and target keys from manifest file. After doing this, when I ran cargo build, it didn't give any warnings but my configs were still unused.

When I ran cargo build --target=wasm32-unknown-emscripten, I'm still getting linker error.

Am I doing something wrong?

[behnam]

Unfortunately, I don't have any experience with wasm/emscripten, so won't be able to help. But there are many posts on the users forum which may give you a hint. It would also help you finding an answer if you share the exact error messages you are receiving. Hope you can get it fixed soon.

[yugoja]

Thanks for you help @behnam!

I'll close this issue and head over to users forum.