How do I use conditional compilation with `cfg` and Cargo?

by

You have to introduce the existing features in your Cargo.toml.

I was able to conditionally compile by doing the following:

  • In Cargo.toml, create a features section and introduce a certain feature name:

    [features]

customfeature = [] # feature has no explicit dependencies

    If you want your feature to have specific dependencies check the examples in the documentation.

  • In your code, use #[cfg(feature="customfeature")]

  • Run cargo build --features customfeature

Since your steps 2 & 3 seem to be fine, there must probably be a problem with your Cargo.toml.

More Related Contents:

  1. Package with both a library and a binary?
  2. Why are Rust executables so huge?
  3. How do I ‘pass down’ feature flags to subdependencies in Cargo?
  4. How do you enable a Rust “crate feature”?
  5. What is a crate attribute and where do I add it?
  6. How can a Rust program access metadata from its Cargo package?
  7. How do I specify the linker path in Rust?
  8. Can Cargo download and build dependencies without also building the application?
  9. Is there a list of all cfg features?
  10. How to idiomatically alias a crate in Rust 2018?
  11. How to tell what “features” are available per crate?
  12. How can I build multiple binaries with Cargo?
  13. How to pass rustc flags to cargo?
  14. How do I pin indirect dependencies of a crate?
  15. Why can’t I store a value and a reference to that value in the same struct?
  16. The compiler suggests I add a ‘static lifetime because the parameter type may not live long enough, but I don’t think that’s what I want
  17. Why does Iterator::take_while take ownership of the iterator?
  18. When should I implement std::convert::From vs std::convert::Into?
  19. How can I call a mutating method while holding a reference to self?
  20. How do you actually use dynamically sized types in Rust?
  21. How do I use the Entry API with an expensive key that is only constructed if the Entry is Vacant?
  22. “parameter `’a` is never used” error when ‘a is used in type parameter bound
  23. Borrowing references to attributes in a struct
  24. How do I split a string in Rust?
  25. Is it possible to implement methods on type aliases?
  26. How to model complex recursive data structures (graphs)?
  27. How can I define an async method in a trait?
  28. Why does the Rust compiler request I constrain a generic type parameter’s lifetime (error E0309)?
  29. Cannot pass self as callback parameter due to double borrowing
  30. How do I create a HashMap with type erased keys?

Leave a Comment