Add `size_of` and `size_of_val` and `align_of` and `align_of_val` to the prelude
(Note: need to update the PR to add `align_of` and `align_of_val`, and remove the second commit with the myriad changes to appease the lint.)
Many, many projects use `size_of` to get the size of a type. However,
it's also often equally easy to hardcode a size (e.g. `8` instead of
`size_of::<u64>()`). Minimizing friction in the use of `size_of` helps
ensure that people use it and make code more self-documenting.
The name `size_of` is unambiguous: the name alone, without any prefix or
path, is self-explanatory and unmistakeable for any other functionality.
Adding it to the prelude cannot produce any name conflicts, as any local
definition will silently shadow the one from the prelude. Thus, we don't
need to wait for a new edition prelude to add it.
Fix typo in the docs of `HashMap::raw_entry_mut`
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Explain differences between `{Once,Lazy}{Cell,Lock}` types
The question of "which once-ish cell-ish type should I use?" has been raised multiple times, and is especially important now that we have stabilized the `LazyCell` and `LazyLock` types. The answer for the `Lazy*` types is that you would be better off using them if you want to use what is by far the most common pattern: initialize it with a single nullary function that you would call at every `get_or_init` site. For everything else there's the `Once*` types.
"For everything else" is a somewhat weak motivation, as it only describes by negation. While contrasting them is inevitable, I feel positive motivations are more understandable. For this, I now offer a distinct example that helps explain why `OnceLock` can be useful, despite `LazyLock` existing: you can do some cool stuff with it that `LazyLock` simply can't support due to its mere definition.
The pair of `std::sync::*Lock`s are usable inside a `static`, and can serve roles in async or multithreaded (or asynchronously multithreaded) programs that `*Cell`s cannot. Because of this, they received most of my attention.
Fixes#124696Fixes#125615
Change pedantically incorrect OnceCell/OnceLock wording
While the semantic intent of a OnceCell/OnceLock is that it can only be written to once (upon init), the fact of the matter is that both these types offer a `take(&mut self) -> Option<T>` mechanism that, when successful, resets the cell to its initial state, thereby [technically allowing it to be written to again](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=415c023a6ae1ef35f371a2d3bb1aa735)
Despite the fact that this can only happen with a mutable reference (generally only used during the construction of the OnceCell/OnceLock), it would be incorrect to say that the type itself as a whole *categorically* prevents being initialized or written to more than once (since it is possible to imagine an identical type only without the `take()` method that actually fulfills that contract).
To clarify, change "that cannot be.." to "that nominally cannot.." and add a note to OnceCell about what can be done with an `&mut Self` reference.
```@rustbot``` label +A-rustdocs
Make TLS accessors closures that return pointers
The current TLS macros generate a function that returns an `Option<&'static T>`. This is both risky as we lie about lifetimes, and necessitates that those functions are `unsafe`. By returning a `*const T` instead, the accessor function do not have safety requirements any longer and can be made closures without hassle. This PR does exactly that!
For native TLS, the closure approach makes it trivial to select the right accessor function at compile-time, which could result in a slight speed-up (I have the hope that the accessors are now simple enough for the MIR-inliner to kick in).
on netbsd, procfs is not as central as on linux/solaris thus
can be perfectly not mounted.
Thus using fcntl with F_GETPATH, the kernel deals with MAXPATHLEN
internally too.
While slightly verbose, it helps explain "why bother with OnceLock?"
This is a point of confusion that has been raised multiple times
shortly before and after the stabilization of LazyLock.
This example is spiritually an example of LazyLock, as it computes a
variable at runtime but accepts no inputs into that process.
It is also slightly simpler and thus easier to understand.
Change it to an even-more concise version and move it to LazyLock.
The example now editorializes slightly more. This may be unnecessary,
but it can be educational for the reader.
std::pal::unix::thread fetching min stack size on netbsd.
PTHREAD_STACK_MIN is not defined however sysconf/_SC_THREAD_STACK_MIN returns it as it can vary from arch to another.
Make `std::env::{set_var, remove_var}` unsafe in edition 2024
Allow calling these functions without `unsafe` blocks in editions up until 2021, but don't trigger the `unused_unsafe` lint for `unsafe` blocks containing these functions.
Fixes#27970.
Fixes#90308.
CC #124866.
Allow calling these functions without `unsafe` blocks in editions up
until 2021, but don't trigger the `unused_unsafe` lint for `unsafe`
blocks containing these functions.
Fixes#27970.
Fixes#90308.
CC #124866.
Make more of the test suite run on Mac Catalyst
Combined with https://github.com/rust-lang/rust/pull/125225, the only failing parts of the test suite are in `tests/rustdoc-js`, `tests/rustdoc-js-std` and `tests/debuginfo`. Tested with:
```console
./x test --target=aarch64-apple-ios-macabi library/std
./x test --target=aarch64-apple-ios-macabi --skip=tests/rustdoc-js --skip=tests/rustdoc-js-std --skip=tests/debuginfo tests
```
Will probably put up a PR later to enable _running_ on (not just compiling for) Mac Catalyst in CI, though not sure where exactly I should do so? `src/ci/github-actions/jobs.yml`?
Note that I've deliberately _not_ enabled stack overflow handlers on iOS/tvOS/watchOS/visionOS (see https://github.com/rust-lang/rust/issues/25872), but rather just skipped those tests, as it uses quite a few APIs that I'd be weary about getting rejected by the App Store (note that Swift doesn't do it on those platforms either).
r? ``@workingjubilee``
CC ``@thomcc``
``@rustbot`` label O-ios O-apple
This adds the `only-apple`/`ignore-apple` compiletest directive, and
uses that basically everywhere instead of `only-macos`/`ignore-macos`.
Some of the updates in `run-make` are a bit redundant, as they use
`ignore-cross-compile` and won't run on iOS - but using Apple in these
is still more correct, so I've made that change anyhow.
Less syscalls for the `copy_file_range` probe
If it's obvious from the actual syscall results themselves that the syscall is supported or unsupported, don't do an extra syscall with an invalid file descriptor.
CC #122052
Panic if `PathBuf::set_extension` would add a path separator
This is likely never intended and potentially a security vulnerability if it happens.
I'd guess that it's mostly literal strings that are passed to this function in practice, so I'm guessing this doesn't break anyone.
CC #125060
While the semantic intent of a OnceCell/OnceLock is that it can only be written
to once (upon init), the fact of the matter is that both these types offer a
`take(&mut self) -> Option<T>` mechanism that, when successful, resets the cell
to its initial state, thereby technically allowing it to be written to again.
Despite the fact that this can only happen with a mutable reference (generally
only used during the construction of the OnceCell/OnceLock), it would be
incorrect to say that the type itself as a whole categorically prevents being
initialized or written to more than once (since it is possible to imagine an
identical type only without the `take()` method that actually fulfills that
contract).
To clarify, change "that cannot be.." to "that nominally cannot.." and add a
note to OnceCell about what can be done with an `&mut Self` reference.
Rollup of 6 pull requests
Successful merges:
- #125263 (rust-lld: fallback to rustc's sysroot if there's no path to the linker in the target sysroot)
- #125345 (rustc_codegen_llvm: add support for writing summary bitcode)
- #125362 (Actually use TAIT instead of emulating it)
- #125412 (Don't suggest adding the unexpected cfgs to the build-script it-self)
- #125445 (Migrate `run-make/rustdoc-with-short-out-dir-option` to `rmake.rs`)
- #125452 (Cleanup check-cfg handling in core and std)
r? `@ghost`
`@rustbot` modify labels: rollup
Cleanup check-cfg handling in core and std
Follow-up to https://github.com/rust-lang/rust/pull/125296 where we:
- expect any feature cfg in std, due to `#[path]` imports
- move some check-cfg args inside the `build.rs` as per Cargo recommendation
- and replace the fake Cargo feature `"restricted-std"` by the custom cfg `restricted_std`
Fixes https://github.com/rust-lang/rust/pull/125296#issuecomment-2127009301
r? `@bjorn3` (maybe, feel free to re-roll)
Use functions from `crt_externs.h` on iOS/tvOS/watchOS/visionOS
Use `_NSGetEnviron`, `_NSGetArgc` and `_NSGetArgv` on iOS/tvOS/watchOS/visionOS, see each commit and the code comments for details. This allows us to unify more code with the macOS implementation, as well as avoiding linking to the `Foundation` framework (which is good for startup performance).
The biggest problem with doing this would be if it lead to App Store rejections. After doing a bunch of research on this, while [it did happen once in 2009](https://blog.unity.com/engine-platform/unity-app-store-submissions-problem-solved), I find it fairly unlikely to happen nowadays, especially considering that Apple has later _added_ `crt_externs.h` to the iOS/tvOS/watchOS/visionOS SDKs, strongly signifying the functions therein is indeed supported on those platforms (even though they lack an availability attribute).
That we've been overly cautious here has also been noted by `@thomcc` in https://github.com/rust-lang/rust/pull/117910#issuecomment-1903372350.
r? `@workingjubilee`
`@rustbot` label O-apple
The behavior makes sense because `Path::new("one_component").parent() ==
Some(Path::new(""))`, so if one naively wants to create the parent
directory for a file to be written, it simply works.
Closes#105108 by documenting the current behavior.
switch to the default implementation of `write_vectored`
HermitOS doesn't support write_vectored and switch to the default implementation of `write_vectored`.
Fix `read_exact` and `read_buf_exact` for `&[u8]` and `io:Cursor`
- Drain after `read_exact` and `read_buf_exact`
- Append to cursor in `read_buf_exact`
revise the interpretation of ReadDir for HermitOS
HermitOS supports getdents64. As under Linux, the dirent64 entry `d_off` is not longer used, because its definition is not clear. Instead of `d_off` the entry `d_reclen` is used to determine the end of the dirent64 entry.
In addition, take up `@workingjubilee` suggestion from the discussions in rust-lang/rust#115984 to increase the readability.
Hermit is a tier 3 platform and this PR changes only files, wich are related to the tier 3 platform.
Update documentation related to the recent cmd.exe fix
Fix some grammar nits, change `bat` (extension) -> `batch` (file), and make line wrapping more consistent.
If we're comfortable using `_NSGetEnviron` from `crt_externs.h`, there shouldn't be an issue with using these either, and then we can merge with the macOS implementation.
This also fixes two test cases on Mac Catalyst:
- `tests/ui/command/command-argv0.rs`, maybe because `[[NSProcessInfo processInfo] arguments]` somehow converts the name of the first argument?
- `tests/ui/env-funky-keys.rs` since we no longer link to Foundation.
Many, many projects use `size_of` to get the size of a type. However,
it's also often equally easy to hardcode a size (e.g. `8` instead of
`size_of::<u64>()`). Minimizing friction in the use of `size_of` helps
ensure that people use it and make code more self-documenting.
The name `size_of` is unambiguous: the name alone, without any prefix or
path, is self-explanatory and unmistakeable for any other functionality.
Adding it to the prelude cannot produce any name conflicts, as any local
definition will silently shadow the one from the prelude. Thus, we don't
need to wait for a new edition prelude to add it.
Add `size_of_val`, `align_of`, and `align_of_val` as well, with similar
justification: widely useful, self-explanatory, unmistakeable for
anything else, won't produce conflicts.
This is likely never intended and potentially a security vulnerability
if it happens.
I'd guess that it's mostly literal strings that are passed to this
function in practice, so I'm guessing this doesn't break anyone.
CC #125060
std::alloc: use posix_memalign instead of memalign on solarish
`memalign` on Solarish requires the alignment to be at least the size of a pointer, which we did not honor. `posix_memalign` also requires that, but that code path already takes care of this requirement.
close GH-124787
Convert instances of `target_os = "macos"` to `target_vendor = "apple"`
https://github.com/rust-lang/rust/pull/124491 migrated towards using `target_vendor = "apple"` more, as there's very little difference between iOS, tvOS, watchOS and visionOS. In that PR, I only did the changes where the standard library already had fixes for iOS, that I could confidently apply to the other targets.
However, there's actually also not that big of a gap between macOS and the aforementioned platforms - so in this PR, I've gone through a few of the instances of `target_os = "macos"` and replaced it with `target_vendor = "apple"` to improve support on those platforms, see the commits for details.
r? workingjubilee
CC `@thomcc` `@simlay` (do tell me if I should stop pinging you on these Apple PRs)
`@rustbot` label O-apple
This uses `libc::fcntl`, which, while not explicitly marked as available
in the headers, is already used by `File::sync_all` and `File::sync_data`
on these platforms, so should be fine to use here as well.
Tested in the iOS simulator with something like:
```
let mut buf = vec![0; c_int::MAX as usize - 1 + 2];
let read_bytes = f.read(&mut buf).unwrap();
```
The code is written in a way to support 32-bit iOS and tvOS ARM devices,
for future compatibility even though we currently only have a target for
32-bit iOS ARM.
library/std: Fix build for NetBSD targets with 32-bit `c_long`
This fixes building `std` for targets like `mipsel-unknown-netbsd`.
If `c_long` is an `i64`, this conversion works with `Into`. But if it's an `i32`, this failed to convert a `u32` to an `i32`.
This fixes building `std` for targets like `mipsel-unknown-netbsd`.
If `c_long` is an `i64`, this conversion works with `Into`. But if it's
an `i32`, this failed to convert a `u32` to an `i32`.
Improve several `Read` implementations
- `read_to_end` and `read_to_string` for `Cursor`
- Error on OOM in `read_to_string` of `&[u8]` and `VecDeque<u8>`
- Avoid making the slices contiguous in `VecDeque::read_to_string`
- ~`read_exact` and (unstable) `read_buf_exact` for `Take`~
- ~`read_buf` for `UnixStream` and `&UnixStream`~ (moved to #123084)
- `read_to_end` for `ChildStdErr`
Move thread parking to `sys::sync`
Part of #117276.
I'll leave the platform-specific API abstractions in `sys::pal`, as per the initial proposal. I'm not entirely sure whether we'll want to keep it that way, but that remains to be seen.
r? ``@ChrisDenton`` (if you have time)
Reduce code size of `thread::set_current`
#123265 introduced a rather large binary size regression, because it added an `unwrap()` call on a `Result<(), Thread>`, which in turn pulled its rather heavy `Debug` implementation. This PR fixes this by readding the `rtassert!` that was removed.
Change `SIGPIPE` ui from `#[unix_sigpipe = "..."]` to `-Zon-broken-pipe=...`
In the stabilization [attempt](https://github.com/rust-lang/rust/pull/120832) of `#[unix_sigpipe = "sig_dfl"]`, a concern was [raised ](https://github.com/rust-lang/rust/pull/120832#issuecomment-2007394609) related to using a language attribute for the feature: Long term, we want `fn lang_start()` to be definable by any crate, not just libstd. Having a special language attribute in that case becomes awkward.
So as a first step towards the next stabilization attempt, this PR changes the `#[unix_sigpipe = "..."]` attribute to a compiler flag `-Zon-broken-pipe=...` to remove that concern, since now the language is not "contaminated" by this feature.
Another point was [also raised](https://github.com/rust-lang/rust/pull/120832#issuecomment-1987023484), namely that the ui should not leak **how** it does things, but rather what the **end effect** is. The new flag uses the proposed naming. This is of course something that can be iterated on further before stabilization.
Tracking issue: https://github.com/rust-lang/rust/issues/97889
default_alloc_error_hook: explain difference to default __rdl_oom in alloc
Though I'm not sure if that is really the reason that this code is duplicated. On no_std it may already be possible to call user-defined code on allocation failure.
Fix HorizonOS build broken by #124210
HorizonOS (for the Tier-3 target `armv6k-nintendo-3ds`) does not support `dirfd()`, as many other similar targets.
In the stabilization attempt of `#[unix_sigpipe = "sig_dfl"]`, a concern
was raised related to using a language attribute for the feature: Long
term, we want `fn lang_start()` to be definable by any crate, not just
libstd. Having a special language attribute in that case becomes
awkward.
So as a first step towards towards the next stabilization attempt, this
PR changes the `#[unix_sigpipe = "..."]` attribute to a compiler flag
`-Zon-broken-pipe=...` to remove that concern, since now the language
is not "contaminated" by this feature.
Another point was also raised, namely that the ui should not leak
**how** it does things, but rather what the **end effect** is. The new
flag uses the proposed naming. This is of course something that can be
iterated on further before stabilization.
Use `target_vendor = "apple"` instead of `target_os = "..."`
Use `target_vendor = "apple"` instead of `all(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos", target_os = "visionos")`.
The apple targets are quite close to being identical, with iOS, tvOS, watchOS and visionOS being even closer, so using `target_vendor` when possible makes it clearer when something is actually OS-specific, or just Apple-specific.
Note that `target_vendor` will [be deprecated in the future](https://github.com/rust-lang/rust/issues/100343), but not before an alternative (like `target_family = "apple"`) is available.
While doing this, I found various inconsistencies and small mistakes in the standard library, see the commits for details. Will follow-up with an extra PR for a similar issue that need a bit more discussion. EDIT: https://github.com/rust-lang/rust/pull/124494
Since you've talked about using `target_vendor = "apple"` in the past:
r? workingjubilee
CC `@simlay,` `@thomcc`
`@rustbot` label O-macos O-ios O-tvos O-watchos O-visionos
`man posix_spawn` documents it to be able to return `ENOENT`, and there
should be nothing preventing this. Tested in the iOS simulator and on
Mac Catalyst.
Abort a process when FD ownership is violated
When an owned FD has already been closed before it's dropped that means something else touched an FD in ways it is not allowed to. At that point things can already be arbitrarily bad, e.g. clobbered mmaps. Recovery is not possible.
All we can do is hasten the fire.
Unlike the previous attempt in #124130 this shouldn't suffer from the possibility that FUSE filesystems can return arbitrary errors.
Unconditionally call `really_init` on GNU/Linux
This makes miri not diverge in behavior, it fixes running Rust linux-gnu binaries on musl with gcompat, it fixes dlopen edge-cases that cranelift somehow hits, etc.
Fixes#124126
thou hast gazed into this abyss with me:
r? ``@ChrisDenton``
This makes miri not diverge in behavior, it fixes running Rust linux-gnu
binaries on musl with gcompat, it fixes dlopen edge-cases that cranelift
somehow hits, etc.
thread_local: be excruciatingly explicit in dtor code
Use raw pointers to accomplish internal mutability, and clearly split references where applicable. This reduces the likelihood that any of these parts are misunderstood, either by humans or the compiler's optimizations.
Fixes#124317
r? ``@joboet``
PathBuf: replace transmuting by accessor functions
The existing `repr(transparent)` was anyway insufficient as `OsString` was not `repr(transparent)`. And furthermore, on Windows it was blatantly wrong as `OsString` wraps `Wtf8Buf` which is a `repr(Rust)` type with 2 fields:
51a7396ad3/library/std/src/sys_common/wtf8.rs (L131-L146)
So let's just be honest about what happens and add accessor methods that make this abstraction-breaking act of PathBuf visible on the APIs that it pierces through.
Fixes https://github.com/rust-lang/rust/issues/124409
windows fill_utf16_buf: explain the expected return value
The comment just says "return what the syscall returns", but that doesn't work for all syscalls as the Windows API is not consistent in how buffer size is negotiated. For instance, GetUserProfileDirectoryW works a bit differently, and so home_dir_crt has to translate this to the usual protocol itself. So it's worth describing that protocol.
r? ``@ChrisDenton``
HermitOS supports getdents64. As under Linux, the dirent64 entry
`d_off` is not longer used, because its definition is not clear.
Instead of `d_off` the entry `d_reclen` is used to determine the
end of the dirent64 entry.
remove an unused type from the reentrant lock tests
At least it seems unused. This was added back in 45aa6c8d1b together with a test related to poisoning; when the test got removed, it seems like it was forgotten to also remove this type.
Fix watchOS and visionOS for pread64 and pwrite64 calls
In #122880, links to `preadv64` and `pwritev64` were added for `watchOS` however the underlying [`weak!` macro did not include `target_os = "watchos"`](c45dee5efd/library/std/src/sys/pal/unix/weak.rs (L30-L74)).
This resulted in an `xcodebuild` error when targeting `watchOS`:
```
Undefined symbols for architecture arm64:
"_preadv64", referenced from:
__rust_extern_with_linkage_preadv64 in libliveview_native_core.a[274](std-324fdd8d31e8eaa2.std.e18cf7e8d0336778-cgu.08.rcgu.o)
"_pwritev64", referenced from:
__rust_extern_with_linkage_pwritev64 in libliveview_native_core.a[274](std-324fdd8d31e8eaa2.std.e18cf7e8d0336778-cgu.08.rcgu.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```
So I added them. I also went ahead and added the same for visionOS because it's bound to create the same issue.
When an EBADF happens then something else already touched an FD in ways it is not allowed to.
At that point things can already be arbitrarily bad, e.g. clobbered mmaps.
Recovery is not possible.
All we can do is hasten the fire.
Use raw-dylib for Windows synchronization functions
Fixes#123999 by using the raw-dylib feature to specify the DLL to load the Windows futex functions from (e.g. [`WaitOnAddress`](https://learn.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-waitonaddress)). This avoids reliance on the import library causing that issue.
With apologies to ``@bjorn3,`` as it's currently necessary to revert this for cranelift.
Add support for Arm64EC to the Standard Library
Adds the final pieces so that the standard library can be built for arm64ec-pc-windows-msvc (initially added in #119199)
* Bumps `windows-sys` to 0.56.0, which adds support for Arm64EC.
* Correctly set the `isEC` parameter for LLVM's `writeArchive` function.
* Add `#![feature(asm_experimental_arch)]` to library crates where Arm64EC inline assembly is used, as it is currently unstable.
Document overrides of `clone_from()` in core/std
As mentioned in https://github.com/rust-lang/rust/pull/96979#discussion_r1379502413
Specifically, when an override doesn't just forward to an inner type, document the behavior and that it's preferred over simply assigning a clone of source. Also, change instances where the second parameter is "other" to "source".
I reused some of the wording over and over for similar impls, but I'm not sure that the wording is actually *good*. Would appreciate feedback about that.
Also, now some of these seem to provide pretty specific guarantees about behavior (e.g. will reuse the exact same allocation iff the len is the same), but I was basing it off of the docs for [`Box::clone_from`](https://doc.rust-lang.org/1.75.0/std/boxed/struct.Box.html#method.clone_from-1) - I'm not sure if providing those strong guarantees is actually good or not.
Use queue-based `RwLock` on more platforms
This switches over Windows 7, SGX and Xous to the queue-based `RwLock` implementation added in #110211, thereby fixing #121949 for Windows 7 and partially resolving #114581 on SGX. TEEOS can't currently be switched because it doesn't have a good thread parking implementation.
CC `@roblabla` `@raoulstrackx` `@xobs` Could you help me test this, please?
r? `@ChrisDenton` the Windows stuff should be familiar to you
zkvm: fix references to `os_str` module
The `os_str` module has been moved to `sys`. This change fixes build issues by changing `use` to point to `crate::sys::os_str`.
Miri on Windows: run .CRT$XLB linker section on thread-end
Hopefully fixes https://github.com/rust-lang/rust/issues/123583
First commit is originally by `@bjorn3`
r? `@oli-obk`
Cc `@ChrisDenton`
Link MSVC default lib in core
## The Problem
On Windows MSVC, Rust invokes the linker directly. This means only the objects and libraries Rust explicitly passes to the linker are used. In short, this is equivalent to passing `-nodefaultlibs`, `-nostartfiles`, etc for gnu compilers.
To compensate for this [the libc crate links to the necessary libraries](a0f5b4b213/src/windows/mod.rs (L258-L261)). The libc crate is then linked from std, thus when you use std you get the defaults back.or integrate with C/C++.
However, this has a few problems:
- For `no_std`, users are left to manually pass the default lib to the linker
- Whereas `std` has the opposite problem, using [`/nodefaultlib`](https://learn.microsoft.com/en-us/cpp/build/reference/nodefaultlib-ignore-libraries?view=msvc-170) doesn't work as expected because Rust treats them as normal libs. This is a particular problem when you want to use e.g. the debug CRT libraries in their place or integrate with C/C++..
## The solution
This PR fixes this in two ways:
- moves linking the default lib into `core`
- passes the lib to the linker using [`/defaultlib`](https://learn.microsoft.com/en-us/cpp/build/reference/defaultlib-specify-default-library?view=msvc-170). This allows users to override it in the normal way (i.e. with [`/nodefaultlib`](https://learn.microsoft.com/en-us/cpp/build/reference/nodefaultlib-ignore-libraries?view=msvc-170)).
This is more or less equivalent to what the MSVC C compiler does. You can see what this looks like in my second commit, which I'll reproduce here for convenience:
```rust
// In library/core
#[cfg(all(windows, target_env = "msvc"))]
#[link(
name = "/defaultlib:msvcrt",
modifiers = "+verbatim",
cfg(not(target_feature = "crt-static"))
)]
#[link(name = "/defaultlib:libcmt", modifiers = "+verbatim", cfg(target_feature = "crt-static"))]
extern "C" {}
```
## Alternatives
- Add the above to `unwind` and `std` but not `core`
- The status quo
- Some other kind of compiler magic maybe
This bares some discussion so I've t-libs nominated it.
Add missing `unsafe` to some internal `std` functions
Adds `unsafe` to a few internal functions that have safety requirements but were previously not marked as `unsafe`. Specifically:
- `std::sys::pal::unix:🧵:min_stack_size` needs to be `unsafe` as `__pthread_get_minstack` might dereference the passed pointer. All callers currently pass a valid initialised `libc::pthread_attr_t`.
- `std:🧵:Thread::new` (and `new_inner`) need to be `unsafe` as it requires the passed thread name to be valid UTF-8, otherwise `Thread::name` will trigger undefined behaviour. I've taken the opportunity to split out the unnamed thread case into a separate `new_unnamed` function to make the safety requirement clearer. All callers meet the safety requirement now that #123505 has been merged.
OpenBSD fix long socket addresses
Original diff from ``@notgull`` in #118349, small changes from me.
on OpenBSD, getsockname(2) returns the actual size of the socket address, and not the len of the content. Figure out the length for ourselves. see https://marc.info/?l=openbsd-bugs&m=170105481926736&w=2Fixes#116523
Thread local updates for idiomatic examples
Update thread local examples to make more idiomatic use of `Cell` for `Copy` types, `RefCell` for non-`Copy` types.
Also shrink the size of `unsafe` blocks, add `SAFETY` comments, and fix `clippy::redundant_closure_for_method_calls`.
Update documentation of Path::to_path_buf and Path::ancestors
`Path::to_path_buf`
> Changes the example from using the qualified path of PathBuf with an import. This is what's done in all other Path/PathBuf examples and makes the code look a bit cleaner.
`Path::ancestors`
> If you take a quick glance at the documentation for Path::ancestors, the unwraps take the natural focus. Potentially indicating that ancestors might panic.
In the reworked version I've also moved the link with parent returning None and that the iterator will always yield &self to before the yield examples.
Feel free to cherry-pick the changes you like.
zkvm: fix path to cmath in zkvm module
I don't know why the original author decided to use relative paths.
I think it would be better to use `use crate::sys::cmath;`
The according issue can be found here https://github.com/risc0/risc0/issues/1647
Remove `sys_common::thread`
Part of #117276.
The stack size calculation isn't system-specific at all and can just live together with the rest of the spawn logic.
Move rare overflow error to a cold function
`scoped.spawn()` generates unnecessary inlined panic-formatting code for a branch that will never be taken.
Panic on overflow in `BorrowedCursor::advance`
Passing `usize::MAX` to `advance` clearly isn't correct, but the current assertion fails to detect this when overflow checks are disabled. This isn't unsound, but should probably be fixed regardless.
Avoid a panic in `set_output_capture` in the default panic handler
This avoid a panic in the default panic handler by not using `set_output_capture` as `OUTPUT_CAPTURE.with` may panic once `OUTPUT_CAPTURE` is dropped.
A new non-panicking `try_set_output_capture` variant of `set_output_capture` is added for use in the default panic handler.
