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Understanding Rust Error E0458

Introduction to Rust Error E0458

Rust Error E0458 occurs when an unknown kind is specified for the link attribute. This error means that you have written a #[link] attribute to import an external library, but the 'kind' field in the attribute does not match the expected values: static, dylib, framework, or raw-dylib.

Example of E0458

#![allow(unused)]
fn main() {
  #[link(kind = "wonderful_unicorn")] extern "C" {}
  // error: unknown kind: `wonderful_unicorn`
}

In the code above, the #[link] attribute has the kind set to "wonderful_unicorn" instead of one of the valid options.

Valid Kinds for the Link Attribute

To resolve Rust Error E0458, specify a valid value for the 'kind' field. The following are the valid kind values you can use with the #[link] attribute: 1. static 2. dylib 3. framework 4. raw-dylib

Examples of Valid Usage

Here are examples showcasing the correct usage for each valid kind value:

1. Static:

#![allow(unused)]
fn main() {
  #[link(kind = "static", name = "example")] extern "C" {}
}

2. Dylib:

#![allow(unused)]
fn main() {
  #[link(kind = "dylib", name = "example")] extern "C" {}
}

3. Framework:

#![allow(unused)]
fn main() {
  #[link(kind = "framework", name = "Example")] extern "C" {}
}

4. Raw-dylib:

#![allow(unused)]
fn main() {
  #[link(kind = "raw-dylib", name = "example")] extern "C" {}
}

Conclusion

To resolve Rust Error E0458, change the 'kind' field of the #[link] attribute to one of the valid values: static, dylib, framework, or raw-dylib. This will ensure that your Rust program correctly loads the external library as intended.

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