src/doc/unstable-book/src/language-features/link-args.md

   1 # `link_args`
   2
   3 The tracking issue for this feature is: [#29596]
   4
   5 [#29596]: https://github.com/rust-lang/rust/issues/29596
   6
   7 ------------------------
   8
   9 You can tell `rustc` how to customize linking, and that is via the `link_args`
  10 attribute. This attribute is applied to `extern` blocks and specifies raw flags
  11 which need to get passed to the linker when producing an artifact. An example
  12 usage would be:
  13
  14 ```rust,no_run
  15 #![feature(link_args)]
  16
  17 #[link_args = "-foo -bar -baz"]
  18 extern "C" {}
  19 # fn main() {}
  20 ```
  21
  22 Note that this feature is currently hidden behind the `feature(link_args)` gate
  23 because this is not a sanctioned way of performing linking. Right now `rustc`
  24 shells out to the system linker (`gcc` on most systems, `link.exe` on MSVC), so
  25 it makes sense to provide extra command line arguments, but this will not
  26 always be the case. In the future `rustc` may use LLVM directly to link native
  27 libraries, in which case `link_args` will have no meaning. You can achieve the
  28 same effect as the `link_args` attribute with the `-C link-args` argument to
  29 `rustc`.
  30
  31 It is highly recommended to *not* use this attribute, and rather use the more
  32 formal `#[link(...)]` attribute on `extern` blocks instead.