How to build with wasm-pack for wasm64 target? - rust

I've tried so far to
[build]
target = "wasm64-unknown-unknown"
In .cargo/config.toml,
and #![cfg(target_arch = "wasm64")]
in my lib.ts
Still, the target directory that I have as a result of wasm-pack build -t web is wasm32-unknown-unknown.
Is there any way to build wasm64-unknown-unknown with wasm-pack?
It works for cargo build, but as I understand only wasm-pack would generate appropriate bindings for JS.

Related

Cargo build includes path in output binary

I'm using cargo build to compile my project.
However, for dependencies the full absolute path is logged in the outputbinary when using strings on the binary.
For example: /home/evrey/.cargo/registry/src/test.net-2dcc6299db9ec823/winit-0.20.0-alpha6/src/platform_impl/linux/x11/window.rs.
How can I remove the private paths from the compiled binary using cargo build?

Depend on the binary of another workspace package being built by cargo

I have a workspace project with multiple packages. The two important ones are:
flowc - which is a lib and a binary
flowstdlib
flowc is a kind of compiler that I build as part of the project.
flowstdlib has a build script, that uses the flowc built binary to build that package (generate "code", files etc), so I need the flowc compiler ready when flowstdlib is to be built.
In cargo.toml of flowstdlib I define flowc as a build dependency:
[build-dependencies]
flowc = {path = "../flowc", version = "0.31.0" }`
(I've tried making it also a dependency, but no change)
in the build.rs of flowstdlib I look for it in the path, and if not found in the ../target/debug/flowc location:
let flowc = if Path::new(env!("CARGO_MANIFEST_DIR")).join("../target/debug/flowc").exists() {
"../target/debug/flowc"
} else if Simpath::new("PATH").find_type("flowc", FileType::File).is_ok() {
"flowc"
} else {
""
};
When I run the build, it looks like it's trying to build multiple packages at the same time in parallel:
Compiling flowstdlib v0.31.0 (/Users/andrew/workspace/flow/flowstdlib)
Compiling flowsamples v0.31.1 (/Users/andrew/workspace/flow/samples)
warning: Could not find `flowc` in $PATH or `target/debug`, so cannot build flowstdlib
error: failed to run custom build command for `flowsamples v0.31.1 (/Users/andrew/workspace/flow/samples)`
and the flowstdlib build fails as flowc binary is not built yet.
Since the build continues and eventually finishes building flowc, if I re-run the build, it will work the second time around (as flowc binary is now found).
So:
it looks like a build-dependency does wait for the depended-on binary to be built (maybe it waits for the library to be built, hard to tell)
Question
How I can make the build of flowstdlib wait for the completion of the flowc binary?
(without forcing a non-parallel build)
Pending the RFC landing, my workaround is to split the build into two commands (I'm using a Makefile to invoke them currently):
* cargo build -p flowc # will complete the build of the flowc binary
* cargo build # will build the entire workspace, including flowstdlib

Error: "linker 'cc' not found" when cross compiling a rust project from windows to linux using cargo

I have a basic rust/cargo project with a single main file and some basic dependencies. The cargo build command works fine when the target is not specified (I am using windows so it builds to windows), but when I try to cross compile the program to linux using cargo build --target=x86_64-unknown-linux-gnu or cargo build --target=x86_64-unknown-linux-musl, the process fails with the following error: linker 'cc' not found.
Does anyone have an idea how to get around this? Is there a specific linker I need to install?
Thanks.
I've just figured it out.
It turns out you need to tell cargo to use the LLVM linker instead. You do this by creating a new directory called .cargo in your base directory, and then a new file called config.toml in this directory. Here you can add the lines:
[target.x86_64-unknown-linux-musl]
rustflags = ["-C", "linker-flavor=ld.lld"]
Then building with the command cargo build --target=x86_64-unknown-linux-musl should work!

Web Assembly and Rust: cargo build vs wasm-pack

Some examples of building wasm use cargo build (like the examples in the book Programming WebAssembly)
cargo build --release --target=wasm32-unknown-unknown
And others use,
wasm-pack build --target web ....
What's the different between these two methods of building a project?
Wasm-pack is a bigger convenience application that provides more than simply building the Rust code.
Amongst other things wasm-pack provides:
Building Rust projects to WebAssembly (equivalent to cargo build --target=wasm32-unknown-unknown ...)
Binding to Node.js
Publishing results to the npm registry.
Creating new projects (like cargo new)
This tool seeks to be a one-stop shop for building and working with rust- generated WebAssembly that you would like to interop with JavaScript, in the browser or with Node.js. wasm-pack helps you build rust-generated WebAssembly packages that you could publish to the npm registry, or otherwise use alongside any javascript packages in workflows that you already use, such as webpack or greenkeeper. 1

How do I run a project's example using Cargo?

I'm trying to run the example code from this project. Following the instructions on the Cargo docs, I did the following:
git clone https://github.com/basiliscos/rust-procol-ftp-client
cd rust-procol-ftp-client
cargo run
cargo test
cargo test should also have compiled the example according to the Rust docs.
Although cargo test executes successfully, when I change into the target/debug directory, I don't find an executable for ftp-get (which is the example code). The target/debug/examples directory is also empty.
What is the best way to go about running this example?
You can run a specific example with:
cargo run --example name_of_example
where name_of_example is the base filename (without .rs)
or to run it in release mode:
cargo run --release --example name_of_example
To pass arguments to the example:
cargo run --example name_of_example -- arguments go here
cargo run will automatically build (or rebuild) the program first if it's out of date.
Try the following:
cd rust-procol-ftp-client
cargo build --examples
./target/debug/examples/ftp-get

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