Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix lang items box example code #47916

Merged
merged 1 commit into from
Feb 3, 2018
Merged

Fix lang items box example code #47916

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
21 changes: 8 additions & 13 deletions src/doc/unstable-book/src/language-features/lang-items.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -37,28 +37,23 @@ unsafe fn allocate(size: usize, _align: usize) -> *mut u8 {
p
}

#[lang = "exchange_free"]
unsafe fn deallocate(ptr: *mut u8, _size: usize, _align: usize) {
libc::free(ptr as *mut libc::c_void)
}

#[lang = "box_free"]
unsafe fn box_free<T: ?Sized>(ptr: *mut T) {
deallocate(ptr as *mut u8, ::core::mem::size_of_val(&*ptr), ::core::mem::align_of_val(&*ptr));
libc::free(ptr as *mut libc::c_void)
}

#[start]
fn main(argc: isize, argv: *const *const u8) -> isize {
let x = box 1;
fn main(_argc: isize, _argv: *const *const u8) -> isize {
let _x = box 1;

0
}

#[lang = "eh_personality"] extern fn rust_eh_personality() {}
#[lang = "panic_fmt"] extern fn rust_begin_panic() -> ! { unsafe { intrinsics::abort() } }
# #[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}
# #[no_mangle] pub extern fn rust_eh_register_frames () {}
# #[no_mangle] pub extern fn rust_eh_unregister_frames () {}
#[lang = "eh_unwind_resume"] extern fn rust_eh_unwind_resume() {}
#[no_mangle] pub extern fn rust_eh_register_frames () {}
#[no_mangle] pub extern fn rust_eh_unregister_frames () {}
```

Note the use of `abort`: the `exchange_malloc` lang item is assumed to
Expand All @@ -80,7 +75,7 @@ Other features provided by lang items include:

Lang items are loaded lazily by the compiler; e.g. if one never uses
`Box` then there is no need to define functions for `exchange_malloc`
and `exchange_free`. `rustc` will emit an error when an item is needed
and `box_free`. `rustc` will emit an error when an item is needed
but not found in the current crate or any that it depends on.

Most lang items are defined by `libcore`, but if you're trying to build
Expand Down Expand Up @@ -318,4 +313,4 @@ the source code.
- `phantom_data`: `libcore/marker.rs`
- `freeze`: `libcore/marker.rs`
- `debug_trait`: `libcore/fmt/mod.rs`
- `non_zero`: `libcore/nonzero.rs`
- `non_zero`: `libcore/nonzero.rs`