# Changes from 0.38.x to 1.x## Silent behavior changes[`rustix::pipe::fcntl_setpipe_size`] now returns the new size, which may begreater than the requested size.[`rustix::pipe::fcntl_setpipe_size`]: https://docs.rs/rustix/1/rustix/pipe/fn.fcntl_setpipe_size.htmlWhen a `&mut Vec<_>` is passed to [`rustix::event::epoll::wait`],[`rustix::event::kqueue::kevent`], or [`rustix::event::port::getn`], thesefunctions previously adjusted the length of the `Vec` to the number of elementswritten, and now do not. A common alternative is to wrap the `&mut Vec<_>`using [`spare_capacity`], and then to clear the `Vec` by iterating using`.drain(..)` after each call. For an example of using `spare_capacity` in thisway, see [here].[`rustix::event::epoll::wait`]: https://docs.rs/rustix/1/rustix/event/epoll/fn.wait.html[`rustix::event::kqueue::kevent`]: https://docs.rs/rustix/1/x86_64-unknown-freebsd/rustix/event/kqueue/fn.kevent.html[`rustix::event::port::getn`]: https://docs.rs/rustix/1/x86_64-unknown-illumos/rustix/event/port/fn.getn.html[`spare_capacity`]: https://docs.rs/rustix/1/rustix/buffer/fn.spare_capacity.html[here]: https://docs.rs/rustix/1/rustix/event/epoll/index.html#examples## API changes`rustix::thread::FutexOperation` and `rustix::thread::futex` are removed. Usethe functions in the [`rustix::thread::futex`] module instead.[`rustix::thread::futex`]: https://docs.rs/rustix/1/rustix/thread/futex/index.html[`rustix::process::waitpid`]'s return type changed from `WaitStatus` to`(Pid, WaitStatus)`, to additionally return the pid of the child.[`rustix::process::waitpid`]: https://docs.rs/rustix/1/rustix/process/fn.waitpid.html[`terminating_signal`] and other functions in [`rustix::process::WaitStatus`] changedfrom returning `u32` to returning `i32`, for better compatibility with the new[`Signal`] type and [`exit`].[`terminating_signal`]: https://docs.rs/rustix/1/rustix/process/struct.WaitStatus.html#method.terminating_signal[`rustix::process::WaitStatus`]: https://docs.rs/rustix/1/rustix/process/struct.WaitStatus.html[`Signal`]: https://docs.rs/rustix/1/rustix/process/struct.Signal.html[`exit`]: std::process::exitThe `SLAVE` flag in [`rustix::mount::MountPropagationFlags`] is renamed to[`DOWNSTREAM`].[`rustix::mount::MountPropagationFlags`]: https://docs.rs/rustix/1/rustix/mount/struct.MountPropagationFlags.html[`DOWNSTREAM`]: https://docs.rs/rustix/1/rustix/mount/struct.MountPropagationFlags.html#associatedconstant.DOWNSTREAMThe "cc" and "libc-extra-traits" features are removed. The "cc" feature hasn'thad any effect for several major releases. If you need the traits provided by"libc-extra-traits", you should instead depend on libc directly and enable its"extra_traits" feature.`rustix::net::Shutdown::ReadWrite` is renamed to[`rustix::net::Shutdown::Both`] to [align with std].[`rustix::net::Shutdown::Both`]: https://docs.rs/rustix/1/rustix/net/enum.Shutdown.html#variant.Both[align with std]: https://doc.rust-lang.org/stable/std/net/enum.Shutdown.html#variant.BothThe `rustix::io_uring::io_uring_register_files_skip` function is replaced witha [`IORING_REGISTER_FILES_SKIP`] constant, similar to the [`rustix::fs::CWD`]constant.[`IORING_REGISTER_FILES_SKIP`]: https://docs.rs/rustix/1/rustix/io_uring/constant.IORING_REGISTER_FILES_SKIP.html[`rustix::fs::CWD`]: https://docs.rs/rustix/1/rustix/fs/constant.CWD.htmlSeveral structs in [`rustix::io_uring`] are now marked `#[non_exhaustive]`because they contain padding or reserved fields. Instead of constructingthem with field values and `..Default::default()`, construct them with`Default::default()` and separately assign the fields.[`rustix::io_uring`]: https://docs.rs/rustix/1/rustix/io_uring/index.html[`rustix::process::Resource`], [`rustix::thread::MembarrierCommand`], and[`rustix::thread::Capability`] are now marked `#[non_exhaustive]` to easemigration in case new constants are defined in the future.[`rustix::process::Resource`]: https://docs.rs/rustix/1/rustix/process/enum.Resource.html[`rustix::thread::MembarrierCommand`]: https://docs.rs/rustix/1/rustix/thread/enum.MembarrierCommand.html[`rustix::thread::Capability`]: https://docs.rs/rustix/1/rustix/thread/enum.Capability.html`rustix::process::WaitidOptions` and `rustix::process::WaitidStatus` arerenamed to[`rustix::process::WaitIdOptions`] and [`rustix::process::WaitIdStatus`] (notethe capitalization), for consistency with [`rustix::process::WaitId`].[`rustix::process::WaitIdOptions`]: https://docs.rs/rustix/1/rustix/process/struct.WaitIdOptions.html[`rustix::process::WaitIdStatus`]: https://docs.rs/rustix/1/rustix/process/struct.WaitIdStatus.html[`rustix::process::WaitId`]: https://docs.rs/rustix/1/rustix/process/enum.WaitId.htmlThe offsets in [`rustix::fs::SeekFrom::Hole`] and[`rustix::fs::SeekFrom::Data`] are changed from `i64` to `u64`, to[align with std], since they represent absolute offsets.[`rustix::fs::SeekFrom::Hole`]: https://docs.rs/rustix/1/rustix/fs/enum.SeekFrom.html#variant.Hole[`rustix::fs::SeekFrom::Data`]: https://docs.rs/rustix/1/rustix/fs/enum.SeekFrom.html#variant.Data[align with std]: https://doc.rust-lang.org/stable/std/io/enum.SeekFrom.html#variant.StartFunctions in [`rustix::net::sockopt`] are renamed to remove the `get_` prefix,to [align with Rust conventions].[`rustix::net::sockopt`]: https://docs.rs/rustix/1/rustix/net/sockopt/index.html[align with Rust conventions]: https://rust-lang.github.io/api-guidelines/naming.html#getter-names-follow-rust-convention-c-getter`rustix::process::sched_*` and `rustix::process::membarrier_*` are moved from[`rustix::process`] to [`rustix::thread`], as they operate on the currentthread rather than the current process.[`rustix::process`]: https://docs.rs/rustix/1/rustix/process/index.html[`rustix::thread`]: https://docs.rs/rustix/1/rustix/thread/index.htmlThe `udata` in [`rustix::event::kqueue::Event`] is changed from `isize` to`*mut c_void` to better propagate pointer provenance. To use arbitrary integervalues, convert using the [`without_provenance_mut`] and the [`.addr()`]functions.[`rustix::event::kqueue::Event`]: https://docs.rs/rustix/1/x86_64-unknown-freebsd/rustix/event/kqueue/struct.Event.html[`without_provenance_mut`]: https://doc.rust-lang.org/stable/std/ptr/fn.without_provenance_mut.html[`.addr()`]: https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.addr`rustix::mount::mount_recursive_bind` is renamed to[`rustix::mount::mount_bind_recursive`]. See [this comment] for details.[`rustix::mount::mount_bind_recursive`]: https://docs.rs/rustix/1/rustix/mount/fn.mount_bind_recursive.html[this comment]: https://github.com/bytecodealliance/rustix/pull/763#issuecomment-1662756184The `rustix::procfs` is removed. This functionality is now available in the[rustix-linux-procfs crate].[rustix-linux-procfs crate]: https://crates.io/crates/rustix-linux-procfs`rustix::net::RecvMsgReturn` is renamed to [`rustix::net::RecvMsg`].[`rustix::net::RecvMsg`]: https://docs.rs/rustix/1/rustix/net/struct.RecvMsg.htmlThe `flags` field of [`rustix::net::RecvMsg`] changed type from [`RecvFlags`]to a new [`ReturnFlags`], since it supports a different set of flags.[`rustix::net::RecvMsg`]: https://docs.rs/rustix/1/rustix/net/struct.RecvMsg.html[`RecvFlags`]: https://docs.rs/rustix/1/rustix/net/struct.RecvFlags.html[`ReturnFlags`]: https://docs.rs/rustix/1/rustix/net/struct.ReturnFlags.html[`rustix::event::poll`]'s and [`rustix::event::epoll`]'s `timeout` argumentchanged from a `c_int` where `-1` means no timeout and non-negative numbersmean a timeout in milliseconds to an `Option<&Timespec>`. The [`Timespec`]'sfields are `tv_sec` which holds seconds and `tv_nsec` which holds nanoseconds.[`rustix::event::poll`]: https://docs.rs/rustix/1/rustix/event/fn.poll.html[`rustix::event::epoll`]: https://docs.rs/rustix/1/rustix/event/epoll/index.html[`Timespec`]: https://docs.rs/rustix/1/rustix/time/struct.Timespec.htmlThe timeout argument in [`rustix::thread::futex::wait`],[`rustix::thread::futex::lock_pi`], [`rustix::thread::futex::wait_bitset`],[`rustix::thread::futex::wait_requeue_pi`], and[`rustix::thread::futex::lock_pi2`] changed from `Option<Timespec>` to`Option<&Timespec>`, for consistency with the rest of rustix's API, and forlow-level efficiency, as it means the implementation doesn't need to make acopy of the `Timespec` to take its address. An easy way to convert an`Option<Timespec>` to an `Option<&Timespec> is to use [`Option::as_ref`].[`rustix::thread::futex::wait`]: https://docs.rs/rustix/1/rustix/thread/futex/fn.wait.html[`rustix::thread::futex::lock_pi`]: https://docs.rs/rustix/1/rustix/thread/futex/fn.lock_pi.html[`rustix::thread::futex::wait_bitset`]: https://docs.rs/rustix/1/rustix/thread/futex/fn.wait_bitset.html[`rustix::thread::futex::wait_requeue_pi`]: https://docs.rs/rustix/1/rustix/thread/futex/fn.wait_requeue_pi.html[`rustix::thread::futex::lock_pi2`]: https://docs.rs/rustix/1/rustix/thread/futex/fn.lock_pi2.html[`Option::as_ref`]: https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.as_refFunctions in [`rustix::event::port`] are renamed to remove the redundant`port_*` prefix.[`rustix::event::port`]: https://docs.rs/rustix/1/x86_64-unknown-illumos/rustix/event/port/index.html`rustix::fs::inotify::InotifyEvent` is renamed to[`rustix::fs::inotify::Event`] to remove the redundant prefix.[`rustix::fs::inotify::Event`]: https://docs.rs/rustix/1/rustix/fs/inotify/struct.Event.html`rustix::fs::StatExt` is removed, and the timestamp fields `st_atime`,`st_mtime`, and `st_ctime` of [`rustix::fs::Stat`] may now be accesseddirectly. They are now signed instead of unsigned, so that they can representtimes before the epoch.[`rustix::fs::Stat`]: https://docs.rs/rustix/1/rustix/fs/struct.Stat.html`rustix::io::is_read_write` is removed, as it's higher-level functionality thatcan be implemented in terms of lower-level rustix calls.[`rustix::net::recv`] and [`rustix::net::recvfrom`] now includethe number of received bytes in their return types, as this number may differfrom the number of bytes written to the buffer when[`rustix::net::RecvFlags::TRUNC`] is used.[`rustix::net::recv`]: https://docs.rs/rustix/1/rustix/net/fn.recv.html[`rustix::net::recvfrom`]: https://docs.rs/rustix/1/rustix/net/fn.recvfrom.html[`rustix::net::RecvFlags::TRUNC`]: https://docs.rs/rustix/1/rustix/net/struct.RecvFlags.html#associatedconstant.TRUNC[`rustix::process::Signal`] constants are now upper-cased; for example,`Signal::Int` is now named [`Signal::INT`]. Also, `Signal` is no longerdirectly convertible to `i32`; use [`Signal::as_raw`] instead.[`rustix::process::Signal`]: https://docs.rs/rustix/1/rustix/process/struct.Signal.html[`Signal::INT`]: https://docs.rs/rustix/1/rustix/process/struct.Signal.html#variant.Int[`Signal::as_raw`]: https://docs.rs/rustix/1/rustix/process/struct.Signal.html#method.as_raw`Signal::from_raw` is renamed to [`Signal::from_named_raw`].[`Signal::from_named_raw`]: https://docs.rs/rustix/1/rustix/process/struct.Signal.html#method.from_named_rawThe associated constant `rustix::ioctl::Ioctl::OPCODE` is now replaced with anassociated method [`rustix::ioctl::Ioctl::opcode`], to support ioctls where theopcode is computed rather than a constant.[`rustix::ioctl::Ioctl::opcode`]: https://docs.rs/rustix/1/rustix/ioctl/trait.Ioctl.html#tymethod.opcodeThe `ifindex` argument in[`rustix::net::sockopt::set_ip_add_membership_with_ifindex`] and[`rustix::net::sockopt::set_ip_drop_membership_with_ifindex`]changed from `i32` to `u32`.[`rustix::net::sockopt::set_ip_add_membership_with_ifindex`]: https://docs.rs/rustix/1/rustix/net/sockopt/fn.set_ip_add_membership_with_ifindex.html[`rustix::net::sockopt::set_ip_drop_membership_with_ifindex`]: https://docs.rs/rustix/1/rustix/net/sockopt/fn.set_ip_drop_membership_with_ifindex.htmlThe `list` argument in [`rustix::fs::listxattr`], [`rustix::fs::flistxattr`],and [`rustix::fs::llistxattr`] changed from `[c_char]`, which is `[i8]` on somearchitectures, to `[u8]`.[`rustix::fs::listxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.listxattr.html[`rustix::fs::flistxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.flistxattr.html[`rustix::fs::llistxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.llistxattr.htmlOn NetBSD, the nanoseconds fields of [`Stat`] have been renamed, for consistencywith other platforms:| Old name       | New Name        || -------------- | --------------- || `st_atimensec` | `st_atime_nsec` || `st_mtimensec` | `st_mtime_nsec` || `st_ctimensec` | `st_ctime_nsec` || `st_birthtimensec` | `st_birthtime_nsec` |[`Stat`]: https://docs.rs/rustix/1/x86_64-unknown-netbsd/rustix/fs/struct.Stat.html[`rustix::mount::mount`]'s `data` argument is now an `Option`, so it can nowbe used in place of `mount2`, and `mount2` is now removed.[`rustix::mount::mount`]: https://docs.rs/rustix/1/rustix/mount/fn.mount.htmlThe [`rustix::net`] functions ending with `_v4`, `_v6`, `_unix` and `_xdp` havebeen merged into a single function that accepts any address type.Specifically, the following functions are removed:  * `bind_any`, `bind_unix`, `bind_v4`, `bind_v6`, `bind_xdp` in favor of    [`bind`],  * `connect_any`, `connect_unix`, `connect_v4`, `connect_v6` in favor of    [`connect`] (leaving address-less [`connect_unspec`]),  * `sendmsg_v4`, `sendmsg_v6`, `sendmsg_unix`, `sendmsg_xdp`, `sendmsg_any` in    favor of [`sendmsg_addr`] (leaving address-less [`sendmsg`]),  * `sendto_any`, `sendto_v4`, `sendto_v6`, `sendto_unix`, `sendto_xdp` in    favor of [`sendto`].[`rustix::net`]: https://docs.rs/rustix/1/rustix/net/index.html[`bind`]: https://docs.rs/rustix/1/rustix/net/fn.bind.html[`connect`]: https://docs.rs/rustix/1/rustix/net/fn.connect.html[`connect_unspec`]: https://docs.rs/rustix/1/rustix/net/fn.connect_unspec.html[`sendmsg_addr`]: https://docs.rs/rustix/1/rustix/net/fn.sendmsg_addr.html[`sendmsg`]: https://docs.rs/rustix/1/rustix/net/fn.sendmsg.html[`sendto`]: https://docs.rs/rustix/1/rustix/net/fn.sendto.htmlThe `SocketAddrAny` enum has changed to a [`SocketAddrAny`] struct which cancontain any kind of socket address. It can be converted to and from the morespecific socket types using `From`/`Into`/`TryFrom`/`TryInto` conversions.[`SocketAddrAny`]: https://docs.rs/rustix/1/rustix/net/struct.SocketAddrAny.htmlThe `len` parameter to [`rustix::fs::fadvise`] has changed from `u64` to`Option<NonZeroU64>`, to reflect that zero is a special case meaning theadvice applies to the end of the file. To convert an arbitrary `u64` value to`Option<NonZeroU64>`, use `NonZeroU64::new`.[`rustix::fs::fadvise`]: https://docs.rs/rustix/1/rustix/fs/fn.fadvise.html[`rustix::io_uring::io_uring_enter`] no longer has `arg` and `size` argumentsproviding a raw `*mut c_void` and `usize` describing the argument value. Topass argumentts, there are now additional functions, `io_uring_enter_sigmask`,and `io_uring_enter_arg`, which take a [`KernelSigSet`] or an`io_uring_getevents_arg`, respectively. These are more ergonomic, and providea better path to adding `IORING_ENTER_EXT_ARG_REG` support in the future.[`rustix::io_uring::io_uring_enter`]: https://docs.rs/rustix/1/rustix/io_uring/fn.io_uring_enter.html[`KernelSigSet`]: https://docs.rs/rustix/1/rustix/io_uring/struct.KernelSigSet.htmlThe [`sigmask`] and [`ts`] fields of [`rustix::io_uring::getevents_arg`]changed from `u64` to [`rustix::io_uring::io_uring_ptr`], to better preservepointer provenance.[`sigmask`]: https://docs.rs/rustix/1/rustix/io_uring/struct.io_uring_getevents_arg.html#structfield.sigmask[`ts`]: https://docs.rs/rustix/1/rustix/io_uring/struct.io_uring_getevents_arg.html#structfield.ts[`rustix::io_uring::getevents_arg`]: https://docs.rs/rustix/1/rustix/io_uring/struct.io_uring_getevents_arg.html[`rustix::io_uring::io_uring_ptr`]: https://docs.rs/rustix/1/rustix/io_uring/struct.io_uring_ptr.htmlThe aliases for [`fcntl_dupfd_cloexec`], [`fcntl_getfd`], and [`fcntl_setfd`]in `rustix::fs` are removed; these functions are just available in[`rustix::io`] now.[`fcntl_dupfd_cloexec`]: https://docs.rs/rustix/1/rustix/io/fn.fcntl_dupfd_cloexec.html[`fcntl_getfd`]: https://docs.rs/rustix/1/rustix/io/fn.fcntl_getfd.html[`fcntl_setfd`]: https://docs.rs/rustix/1/rustix/io/fn.fcntl_setfd.html[`rustix::io`]: https://docs.rs/rustix/1/rustix/io/index.html[`SocketAddrXdp`] no longer has a shared UMEM field. A new[`SocketAddrXdpWithSharedUmem`] is added for the purpose of calling `bind` andpassing it an XDP address with a shared UMEM fd. And `SockaddrXdpFlags` isrenamed to [`SocketAddrXdpFlags`].[`SocketAddrXdp`]: https://docs.rs/rustix/1/rustix/net/xdp/struct.SocketAddrXdp.html[`SocketAddrXdpWithSharedUmem`]: https://docs.rs/rustix/1/rustix/net/xdp/struct.SocketAddrXdpWithSharedUmem.html[`SocketAddrXdpFlags`]: https://docs.rs/rustix/1/rustix/net/xdp/struct.SocketAddrXdpFlags.html[`rustix::io_uring::io_uring_setup`] is now unsafe, due its `io_uring_params`argument optionally containing a raw file descriptor.[`rustix::io_uring::io_uring_setup`]: https://docs.rs/rustix/1/rustix/io_uring/fn.io_uring_setup.htmlThe buffer for [`SendAncillaryBuffer`] and [`RecvAncillaryBuffer`] is nowa `[MaybeUninit<u8>]` instead of a `[u8]`.[`SendAncillaryBuffer`]: https://docs.rs/rustix/1/rustix/net/struct.SendAncillaryBuffer.html[`RecvAncillaryBuffer`]: https://docs.rs/rustix/1/rustix/net/struct.RecvAncillaryBuffer.html[`read`], [`pread`], [`recv`], [`recvfrom`], [`getrandom`], [`readlinkat_raw`],[`epoll::wait`], [`kevent`], [`port::getn`], [`getxattr`], [`lgetxattr`],[`fgetxattr`], [`listxattr`], [`llistxattr`], and [`flistxattr`] now use thenew [`Buffer` trait].This replaces `read_uninit`, `pread_uninit`, `recv_uninit`, `recvfrom_uninit`,and `getrandom_uninit`, as the `Buffer` trait supports reading intouninitialized slices.`epoll::wait`, `kevent`, and `port::getn` previously took a `Vec` which theyimplicitly cleared before results were appended. When passing a `Vec` to`epoll::wait`, `kevent`, or `port::getn` using [`spare_capacity`], the `Vec` isnot cleared first. Consider clearing the vector before calling `epoll::wait`,`kevent`, or `port::getn`, or consuming it using `.drain(..)` before reusing it.[`read`]: https://docs.rs/rustix/1/rustix/io/fn.read.html[`pread`]: https://docs.rs/rustix/1/rustix/io/fn.pread.html[`recv`]: https://docs.rs/rustix/1/rustix/net/fn.recv.html[`recvfrom`]: https://docs.rs/rustix/1/rustix/net/fn.recvfrom.html[`getrandom`]: https://docs.rs/rustix/1/rustix/rand/fn.getrandom.html[`readlinkat_raw`]: https://docs.rs/rustix/1/rustix/fs/fn.readlinkat_raw.html[`epoll::wait`]: https://docs.rs/rustix/1/rustix/event/epoll/fn.wait.html[`getxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.getxattr.html[`lgetxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.lgetxattr.html[`fgetxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.fgetxattr.html[`listxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.listxattr.html[`llistxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.llistxattr.html[`flistxattr`]: https://docs.rs/rustix/1/rustix/fs/fn.flistxattr.html[`kevent`]: https://docs.rs/rustix/1/x86_64-unknown-freebsd/rustix/event/kqueue/fn.kevent.html[`port::getn`]: https://docs.rs/rustix/1/x86_64-unknown-illumos/rustix/event/port/fn.getn.html[`Buffer` trait]: https://docs.rs/rustix/1/rustix/buffer/trait.Buffer.html[`spare_capacity`]: https://docs.rs/rustix/1/rustix/buffer/fn.spare_capacity.htmlThe [`rustix::ioctl::Opcode`] type has changed from a struct to a raw integervalue, and the associated utilities are change to `const` functions. In placeof `ReadOpcode`, `WriteOpcode`, `ReadWriteOpcode`, and `NoneOpcode`, use the`read`, `write`, `read_write`, and `none` const functions in the[`ioctl::opcode`] module. For example, in place of this:```rustioctl::Setter::<ioctl::ReadOpcode<b'U', 15, c_uint>, c_uint>::new(interface)```use this:```rust+ ioctl::Setter::<{ ioctl::opcode::read::<c_uint>(b'U', 15) }, c_uint>::new(interface)```.In place of `BadOpcode`, use the opcode value directly.[`rustix::ioctl::Opcode`]: https://docs.rs/rustix/1/rustix/ioctl/type.Opcode.html[`ioctl::opcode`]: https://docs.rs/rustix/1/rustix/ioctl/opcode/index.html[`rustix::event::port::getn`]'s `min_events` argument is now a `u32`, toreflect the type in the underlying system API.[`rustix::event::port::getn`]: https://docs.rs/rustix/1/x86_64-unknown-illumos/rustix/event/port/fn.getn.htmlAll explicitly deprecated functions and types have been removed. Theirdeprecation messages will have identified alternatives.