Document that write_all will not call write if given an empty buffer
Some types of Write instances have a semantic meaning associated with
writing an empty buffer, such as sending an empty packet. This works
when calling `write` directly, and supplying an empty buffer. However,
calling `write_all` on an empty buffer will simply never call `write`,
because `write_all` assumes it has no work to do.
Document this behavior, to help prospective users of
datagram-packet-style Write instances.
Some types of Write instances have a semantic meaning associated with
writing an empty buffer, such as sending an empty packet. This works
when calling `write` directly, and supplying an empty buffer. However,
calling `write_all` on an empty buffer will simply never call `write`,
because `write_all` assumes it has no work to do.
Document this behavior, to help prospective users of
datagram-packet-style Write instances.
Since the docs for the WASI API are now evolving in [WebAssembly/WASI] repo,
I thought it might be useful to update the links in the docs to point to that location
instead of using the outdated `CraneStation/wasmtime` destination.
[WebAssembly/WASI]: https://github.com/WebAssembly/WASI
Rename `Alloc` to `AllocRef`
The allocator-wg has decided to merge this change upstream in https://github.com/rust-lang/wg-allocators/issues/8#issuecomment-577122958.
This renames `Alloc` to `AllocRef` because types that implement `Alloc` are a reference, smart pointer, or ZSTs. It is not possible to have an allocator like `MyAlloc([u8; N])`, that owns the memory and also implements `Alloc`, since that would mean, that moving a `Vec<T, MyAlloc>` would need to correct the internal pointer, which is not possible as we don't have move constructors.
For further explanation please see https://github.com/rust-lang/wg-allocators/issues/8#issuecomment-489464843 and the comments after that one.
Additionally it clarifies the semantics of `Clone` on an allocator. In the case of `AllocRef`, it is clear that the cloned handle still points to the same allocator instance, and that you can free data allocated from one handle with another handle.
The initial proposal was to rename `Alloc` to `AllocHandle`, but `Ref` expresses the semantics better than `Handle`. Also, the only appearance of `Handle` in `std` are for windows specific resources, which might be confusing.
Blocked on https://github.com/rust-lang/miri/pull/1160
Options IP_MULTICAST_TTL and IP_MULTICAST_LOOP are 1 byte on BSD
Options IP_MULTICAST_TTL and IP_MULTICAST_LOOP are 1 byte on BSD and Solaris
See ip(4P) man page:
IP_MULTICAST_TTL Time to live for multicast datagrams. This option
takes an unsigned character as an argument. Its
value is the TTL that IP uses on outgoing multi-
cast datagrams. The default is 1.
IP_MULTICAST_LOOP Loopback for multicast datagrams. Normally multi-
cast datagrams are delivered to members on the
sending host (or sending zone). Setting the
unsigned character argument to 0 causes the oppo-
site behavior, meaning that when multiple zones
are present, the datagrams are delivered to all
zones except the sending zone.
https://docs.oracle.com/cd/E88353_01/html/E37851/ip-4p.htmlhttps://man.openbsd.org/ip.4
Stabilize ManuallyDrop::take
Tracking issue: closes#55422
FCP merge: https://github.com/rust-lang/rust/issues/55422#issuecomment-572653619
Reclaims the doc improvements from closed#62198.
-----
Stable version is a simple change if necessary.
Proposal: [relnotes] (this changes how to best take advantage of `ManuallyDrop`, esp. wrt. `Drop::drop` and finalize-by-value members)
See ip(4P) man page:
IP_MULTICAST_TTL Time to live for multicast datagrams. This option
takes an unsigned character as an argument. Its
value is the TTL that IP uses on outgoing multi-
cast datagrams. The default is 1.
IP_MULTICAST_LOOP Loopback for multicast datagrams. Normally multi-
cast datagrams are delivered to members on the
sending host (or sending zone). Setting the
unsigned character argument to 0 causes the oppo-
site behavior, meaning that when multiple zones
are present, the datagrams are delivered to all
zones except the sending zone.
https://docs.oracle.com/cd/E88353_01/html/E37851/ip-4p.htmlhttps://man.openbsd.org/ip.4
Don't use f64 shims for f32 cmath functions on non 32-bit x86 MSVC
These shims are only needed on 32-bit x86. Additionally since https://reviews.llvm.org/rL268875 LLVM handles adding the shims itself for the intrinsics.
Use 3.6 instead of 3.5 in float fract() documentation
It is not self-explanatory whether the fract() function inverts the fractional part of negative numbers. This change clarifies this possible question (so that it is `.6` not `.4`)
Clean up some diagnostics by making them more consistent
In general:
- Diagnostic should start with a lowercase letter.
- Diagnostics should not end with a full stop.
- Ellipses contain three dots.
- Backticks should encode Rust code.
I also reworded a couple of messages to make them read more clearly.
It might be sensible to create a style guide for diagnostics, so these informal conventions are written down somewhere, after which we could audit the existing diagnostics.
r? @Centril
It is not self-explanatory whether the fract() function inverts the fractional part of negative numbers.
Co-Authored-By: Mateusz Mikuła <mati865@users.noreply.github.com>
Fix memory leak if C++ catches a Rust panic and discards it
If C++ catches a Rust panic using `catch (...)` and then chooses not to rethrow it, the `Box<dyn Any>` in the exception may be leaked. This PR fixes this by adding the necessary destructors to the exception object.
r? @Mark-Simulacrum
Document behavior of set_nonblocking on UnixListener
The description on `set_nonblocking` in `UnixListener` was rather brief so I adapted it to be more like the documentation of `set_nonblocking` in `TcpListener`.
The link for UNIX was pointing to the Cloud ABI docs. It should have
been pointing to the clock_gettime docs instead. The table is repeated
in the docs for SystemTime, but there the UNIX entry was already correct.
Inline some conversion methods around OsStr
Diff on the assembly of this snippet before and after this PR: https://www.diffchecker.com/NeGMjaJ2
```rust
use std::env;
use std::io;
use std::path::{Path, PathBuf};
pub fn cargo_home_with_cwd(cwd: &Path) -> io::Result<PathBuf> {
match env::var_os("CARGO_HOME").filter(|h| !h.is_empty()) {
Some(home) => {
let home = PathBuf::from(home);
if home.is_absolute() {
Ok(home)
} else {
Ok(cwd.join(&home))
}
}
_ => env::home_dir()
.map(|p| p.join(".cargo"))
.ok_or_else(|| io::Error::new(io::ErrorKind::Other, "could not find cargo home dir")),
}
}
```
build-std compatible sanitizer support
### Motivation
When using `-Z sanitizer=*` feature it is essential that both user code and
standard library is instrumented. Otherwise the utility of sanitizer will be
limited, or its use will be impractical like in the case of memory sanitizer.
The recently introduced cargo feature build-std makes it possible to rebuild
standard library with arbitrary rustc flags. Unfortunately, those changes alone
do not make it easy to rebuild standard library with sanitizers, since runtimes
are dependencies of std that have to be build in specific environment,
generally not available outside rustbuild process. Additionally rebuilding them
requires presence of llvm-config and compiler-rt sources.
The goal of changes proposed here is to make it possible to avoid rebuilding
sanitizer runtimes when rebuilding the std, thus making it possible to
instrument standard library for use with sanitizer with simple, although
verbose command:
```
env CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUSTFLAGS=-Zsanitizer=thread cargo test -Zbuild-std --target x86_64-unknown-linux-gnu
```
### Implementation
* Sanitizer runtimes are no long packed into crates. Instead, libraries build
from compiler-rt are used as is, after renaming them into `librusc_rt.*`.
* rustc obtains runtimes from target libdir for default sysroot, so that
they are not required in custom build sysroots created with build-std.
* The runtimes are only linked-in into executables to address issue #64629.
(in previous design it was hard to avoid linking runtimes into static
libraries produced by rustc as demonstrated by sanitizer-staticlib-link
test, which still passes despite changes made in #64780).
cc @kennytm, @japaric, @firstyear, @choller
Add HashSet::get_or_insert_owned
This is an extension for tracking issue #60896. The more-general `get_or_insert_with` has potential for misuse, so we might remove it, but I think `get_or_insert_owned` covers most use cases.
