Misc improvements, move barrier to safe module.

src/header/pthread/barrier.rs

@@ -1,83 +1,79 @@
 use crate::header::errno::*;
 
-use core::sync::atomic::{AtomicU32 as AtomicUint, AtomicI32 as AtomicInt, Ordering};
+use core::num::NonZeroU32;
+
+use crate::sync::barrier::*;
 
 use super::*;
 
-pub(crate) struct RlctBarrier {
-    pub count: AtomicUint,
-    pub original_count: c_uint,
-    pub epoch: AtomicInt,
-}
+pub(crate) type RlctBarrier = Barrier;
+
+#[derive(Clone, Copy)]
 pub(crate) struct RlctBarrierAttr {
-    pub pshared: c_int,
+    pshared: c_int,
+}
+impl Default for RlctBarrierAttr {
+    fn default() -> Self {
+        // pshared = PTHREAD_PROCESS_PRIVATE is default according to POSIX.
+        Self { pshared: PTHREAD_PROCESS_PRIVATE }
+    }
 }
 
+// Not async-signal-safe.
 #[no_mangle]
 pub unsafe extern "C" fn pthread_barrier_destroy(barrier: *mut pthread_barrier_t) -> c_int {
-    // Behavior is undefined if any thread is currently waiting.
+    // Behavior is undefined if any thread is currently waiting when this is called.
+
+    // No-op, currently.
+    core::ptr::drop_in_place(barrier.cast::<RlctBarrier>());
+
     0
 }
 
+// Not async-signal-safe.
 #[no_mangle]
 pub unsafe extern "C" fn pthread_barrier_init(barrier: *mut pthread_barrier_t, attr: *const pthread_barrierattr_t, count: c_uint) -> c_int {
-    let attr = attr.cast::<RlctBarrierAttr>().as_ref();
+    let attr = attr.cast::<RlctBarrierAttr>().as_ref().copied().unwrap_or_default();
 
-    if count == 0 {
+    let Some(count) = NonZeroU32::new(count) else {
         return EINVAL;
-    }
+    };
 
-    barrier.cast::<RlctBarrier>().write(RlctBarrier {
-        count: AtomicUint::new(0),
-        original_count: count,
-        epoch: AtomicInt::new(0),
-    });
+    barrier.cast::<RlctBarrier>().write(RlctBarrier::new(count));
     0
 }
 
+fn unlikely(condition: bool) -> bool { condition }
+
+// Not async-signal-safe.
 #[no_mangle]
 pub unsafe extern "C" fn pthread_barrier_wait(barrier: *mut pthread_barrier_t) -> c_int {
     let barrier = &*barrier.cast::<RlctBarrier>();
 
-    // TODO: Orderings
-    let mut cached = barrier.count.load(Ordering::SeqCst);
-
-    loop {
-        let new = if cached == barrier.original_count - 1 { 0 } else { cached + 1 };
-
-        match barrier.count.compare_exchange_weak(cached, new, Ordering::SeqCst, Ordering::SeqCst) {
-            Ok(_) => if new == 0 {
-                // We reached COUNT waits, and will thus be the thread notifying every other
-                // waiter.
-
-                todo!();
-
-                return PTHREAD_BARRIER_SERIAL_THREAD;
-            } else {
-                // We increased the wait count, but this was not sufficient. We will thus have to
-                // wait for the epoch to tick up.
-                todo!();
-
-                return 0;
-            }
-            Err(value) => {
-                cached = value;
-                core::hint::spin_loop();
-            }
-        }
+    match barrier.wait() {
+        WaitResult::NotifiedAll => PTHREAD_BARRIER_SERIAL_THREAD,
+        WaitResult::Waited => 0,
     }
 }
 
+// Not async-signal-safe.
 #[no_mangle]
 pub unsafe extern "C" fn pthread_barrierattr_init(attr: *mut pthread_barrierattr_t) -> c_int {
-    // PTHREAD_PROCESS_PRIVATE is default according to POSIX.
-    core::ptr::write(attr.cast::<RlctBarrierAttr>(), RlctBarrierAttr { pshared: PTHREAD_PROCESS_PRIVATE });
+    core::ptr::write(attr.cast::<RlctBarrierAttr>(), RlctBarrierAttr::default());
 
     0
 }
 
+// Not async-signal-safe.
 #[no_mangle]
 pub unsafe extern "C" fn pthread_barrierattr_setpshared(attr: *mut pthread_barrierattr_t, pshared: c_int) -> c_int {
     (*attr.cast::<RlctBarrierAttr>()).pshared = pshared;
     0
 }
+
+// Not async-signal-safe.
+#[no_mangle]
+pub unsafe extern "C" fn pthread_barrierattr_getpshared(attr: *const pthread_barrierattr_t, pshared: *mut c_int) -> c_int {
+    core::ptr::write(pshared, (*attr.cast::<RlctBarrierAttr>()).pshared);
+    0
+}

src/header/pthread/mod.rs

@@ -7,6 +7,13 @@ use crate::platform::{self, Pal, Sys, types::*};
 use crate::header::{sched::*, time::timespec};
 use crate::pthread;
 
+fn e(result: Result<(), pthread::Errno>) -> i32 {
+    match result {
+        Ok(()) => 0,
+        Err(pthread::Errno(error)) => error,
+    }
+}
+
 #[derive(Clone, Copy)]
 pub(crate) struct RlctAttr {
     pub detachstate: c_uchar,
@@ -25,7 +32,7 @@ pub const PTHREAD_CANCEL_ASYNCHRONOUS: c_int = 0;
 pub const PTHREAD_CANCEL_ENABLE: c_int = 1;
 pub const PTHREAD_CANCEL_DEFERRED: c_int = 2;
 pub const PTHREAD_CANCEL_DISABLE: c_int = 3;
-pub const PTHREAD_CANCELED: *mut c_void = core::ptr::null_mut();
+pub const PTHREAD_CANCELED: *mut c_void = (!0_usize) as *mut c_void;
 
 pub const PTHREAD_CREATE_DETACHED: c_int = 0;
 pub const PTHREAD_CREATE_JOINABLE: c_int = 1;
@@ -101,19 +108,34 @@ pub unsafe extern "C" fn pthread_exit(retval: *mut c_void) -> ! {
     pthread::exit_current_thread(pthread::Retval(retval))
 }
 
-// #[no_mangle]
-pub extern "C" fn pthread_getconcurrency() -> c_int {
-    todo!()
+#[no_mangle]
+pub unsafe extern "C" fn pthread_getconcurrency() -> c_int {
+    // Redox and Linux threads are 1:1, not M:N.
+    1
 }
 
-// #[no_mangle]
-pub extern "C" fn pthread_getcpuclockid(thread: pthread_t, clock: *mut clockid_t) -> c_int {
-    todo!()
+#[no_mangle]
+pub unsafe extern "C" fn pthread_getcpuclockid(thread: pthread_t, clock_out: *mut clockid_t) -> c_int {
+    match pthread::get_cpu_clkid(&*thread.cast()) {
+        Ok(clock) => {
+            clock_out.write(clock);
+            0
+        }
+        Err(pthread::Errno(error)) => error,
+    }
 }
 
-// #[no_mangle]
-pub extern "C" fn pthread_getschedparam(thread: pthread_t, policy: *mut clockid_t, param: *mut sched_param) -> c_int {
-    todo!()
+#[no_mangle]
+pub unsafe extern "C" fn pthread_getschedparam(thread: pthread_t, policy_out: *mut c_int, param_out: *mut sched_param) -> c_int {
+    match pthread::get_sched_param(&*thread.cast()) {
+        Ok((policy, param)) => {
+            policy_out.write(policy);
+            param_out.write(param);
+
+            0
+        }
+        Err(pthread::Errno(error)) => error,
+    }
 }
 
 pub mod tls;
@@ -143,22 +165,40 @@ pub use self::rwlock::*;
 pub unsafe extern "C" fn pthread_self() -> pthread_t {
     pthread::current_thread().unwrap_unchecked() as *const _ as *mut _
 }
-pub extern "C" fn pthread_setcancelstate(state: c_int, oldstate: *mut c_int) -> c_int {
-    todo!();
+#[no_mangle]
+pub unsafe extern "C" fn pthread_setcancelstate(state: c_int, oldstate: *mut c_int) -> c_int {
+    match pthread::set_cancel_state(state) {
+        Ok(old) => {
+            oldstate.write(old);
+            0
+        }
+        Err(pthread::Errno(error)) => error,
+    }
 }
-pub extern "C" fn pthread_setcanceltype(ty: c_int, oldty: *mut c_int) -> c_int {
-    todo!();
+#[no_mangle]
+pub unsafe extern "C" fn pthread_setcanceltype(ty: c_int, oldty: *mut c_int) -> c_int {
+    match pthread::set_cancel_type(ty) {
+        Ok(old) => {
+            oldty.write(old);
+            0
+        }
+        Err(pthread::Errno(error)) => error,
+    }
 }
 
+#[no_mangle]
 pub extern "C" fn pthread_setconcurrency(concurrency: c_int) -> c_int {
-    todo!();
+    // Redox and Linux threads are 1:1, not M:N.
+    0
 }
 
-pub extern "C" fn pthread_setschedparam(thread: pthread_t, policy: c_int, param: *const sched_param) -> c_int {
-    todo!();
+#[no_mangle]
+pub unsafe extern "C" fn pthread_setschedparam(thread: pthread_t, policy: c_int, param: *const sched_param) -> c_int {
+    e(pthread::set_sched_param(&*thread.cast(), policy, &*param))
 }
-pub extern "C" fn pthread_setschedprio(thread: pthread_t, prio: c_int) -> c_int {
-    todo!();
+#[no_mangle]
+pub unsafe extern "C" fn pthread_setschedprio(thread: pthread_t, prio: c_int) -> c_int {
+    e(pthread::set_sched_priority(&*thread.cast(), prio))
 }
 
 pub mod spin;

src/header/pthread/mutex.rs

@@ -1,18 +1,27 @@
 use super::*;
 
-use crate::header::errno::EBUSY;
+use crate::header::errno::*;
 
 use core::sync::atomic::AtomicI32 as AtomicInt;
 
-// PTHREAD_MUTEX_INITIALIZER
+// PTHREAD_MUTEX_INITIALIZER is defined in bits_pthread/cbindgen.toml
+
+#[repr(u8)]
+enum State {
+    Unlocked,
+    Locked,
+    Waiting,
+}
 
 // #[no_mangle]
-pub extern "C" fn pthread_mutex_consistent(mutex: *mut pthread_mutex_t) -> c_int {
-    todo!();
+pub unsafe extern "C" fn pthread_mutex_consistent(mutex: *mut pthread_mutex_t) -> c_int {
+    let mutex = &*mutex.cast::<RlctMutex>();
+
+    todo!()
 }
 #[no_mangle]
 pub unsafe extern "C" fn pthread_mutex_destroy(mutex: *mut pthread_mutex_t) -> c_int {
-    let _mutex: &pthread_mutex_t = &*mutex;
+    let _mutex = &mut *mutex.cast::<RlctMutex>();
     0
 }
 
@@ -23,11 +32,20 @@ pub extern "C" fn pthread_mutex_getprioceiling(mutex: *const pthread_mutex_t, pr
 
 #[no_mangle]
 pub unsafe extern "C" fn pthread_mutex_init(mutex: *mut pthread_mutex_t, attr: *const pthread_mutexattr_t) -> c_int {
-    let attr = attr.cast::<RlctMutexAttr>().as_ref();
+    let attr = attr.cast::<RlctMutexAttr>().as_ref().copied().unwrap_or_default();
 
     // TODO: attr
     mutex.cast::<RlctMutex>().write(RlctMutex {
         inner: crate::sync::mutex::UNLOCKED.into(),
+        /*robust: attr.robust != 0,
+        ty: match attr.ty {
+            PTHREAD_MUTEX_DEFAULT => Ty::Def,
+            PTHREAD_MUTEX_ERRORCHECK => Ty::Errck,
+            PTHREAD_MUTEX_RECURSIVE => Ty::Recursive,
+            PTHREAD_MUTEX_NORMAL => Ty::Normal,
+
+            _ => return EINVAL,
+        }*/
     });
     0
 }
@@ -68,7 +86,10 @@ pub unsafe extern "C" fn pthread_mutex_unlock(mutex: *mut pthread_mutex_t) -> c_
 }
 
 #[no_mangle]
-pub extern "C" fn pthread_mutexattr_destroy(_attr: *mut pthread_mutexattr_t) -> c_int {
+pub unsafe extern "C" fn pthread_mutexattr_destroy(attr: *mut pthread_mutexattr_t) -> c_int {
+    // No-op
+
+    core::ptr::drop_in_place(attr);
     0
 }
 
@@ -102,14 +123,7 @@ pub unsafe extern "C" fn pthread_mutexattr_gettype(attr: *const pthread_mutexatt
 }
 #[no_mangle]
 pub unsafe extern "C" fn pthread_mutexattr_init(attr: *mut pthread_mutexattr_t) -> c_int {
-    attr.cast::<RlctMutexAttr>().write(RlctMutexAttr {
-        robust: PTHREAD_MUTEX_STALLED,
-        pshared: PTHREAD_PROCESS_PRIVATE,
-        protocol: PTHREAD_PRIO_NONE,
-        // TODO
-        prioceiling: 0,
-        ty: PTHREAD_MUTEX_DEFAULT,
-    });
+    attr.cast::<RlctMutexAttr>().write(RlctMutexAttr::default());
     0
 }
 
@@ -144,10 +158,23 @@ pub unsafe extern "C" fn pthread_mutexattr_settype(attr: *mut pthread_mutexattr_
 
 #[repr(C)]
 pub(crate) struct RlctMutex {
-    pub inner: AtomicInt,
+    // Actual locking word. Allows the states UNLOCKED, LOCKED, and WAITING, a substate of LOCKED.
+    inner: AtomicInt,
+
+    /*robust: bool,
+    ty: Ty,*/
+
+    // TODO: Robust mutexes
+}
+enum Ty {
+    Normal,
+    Def,
+    Errck,
+    Recursive,
 }
 
 #[repr(C)]
+#[derive(Clone, Copy)]
 pub(crate) struct RlctMutexAttr {
     pub prioceiling: c_int,
     pub protocol: c_int,
@@ -155,4 +182,15 @@ pub(crate) struct RlctMutexAttr {
     pub robust: c_int,
     pub ty: c_int,
 }
-
+impl Default for RlctMutexAttr {
+    fn default() -> Self {
+        Self {
+            robust: PTHREAD_MUTEX_STALLED,
+            pshared: PTHREAD_PROCESS_PRIVATE,
+            protocol: PTHREAD_PRIO_NONE,
+            // TODO
+            prioceiling: 0,
+            ty: PTHREAD_MUTEX_DEFAULT,
+        }
+    }
+}

src/pthread/mod.rs

@@ -24,7 +24,8 @@ const MAIN_PTHREAD_ID: usize = 1;
 pub unsafe fn init() {
     let obj = Box::into_raw(Box::new(Pthread {
         waitval: Waitval::new(),
-        wants_cancel: AtomicBool::new(false),
+        has_enabled_cancelation: AtomicBool::new(false),
+        has_queued_cancelation: AtomicBool::new(false),
         flags: PthreadFlags::empty().bits().into(),
 
         // TODO
@@ -51,7 +52,8 @@ bitflags::bitflags! {
 
 pub struct Pthread {
     waitval: Waitval<Retval>,
-    wants_cancel: AtomicBool,
+    has_queued_cancelation: AtomicBool,
+    has_enabled_cancelation: AtomicBool,
     flags: AtomicUsize,
 
     stack_base: *mut c_void,
@@ -123,7 +125,8 @@ pub(crate) unsafe fn create(attrs: Option<&header::RlctAttr>, start_routine: ext
     let pthread = Pthread {
         waitval: Waitval::new(),
         flags: flags.bits().into(),
-        wants_cancel: AtomicBool::new(false),
+        has_enabled_cancelation: AtomicBool::new(false),
+        has_queued_cancelation: AtomicBool::new(false),
         stack_base,
         stack_size,
         os_tid: UnsafeCell::new(OsTid::default()),
@@ -211,7 +214,7 @@ unsafe extern "C" fn new_thread_shim(
 pub unsafe fn join(thread: &Pthread) -> Result<Retval, Errno> {
     // We don't have to return EDEADLK, but unlike e.g. pthread_t lifetime checking, it's a
     // relatively easy check.
-    if core::ptr::eq(thread, current_thread().unwrap_unchecked()) {
+    if core::ptr::eq(thread, current_thread().expect("current thread not present")) {
         return Err(Errno(EDEADLK));
     }
 
@@ -243,7 +246,9 @@ pub fn current_thread() -> Option<&'static Pthread> {
 }
 
 pub unsafe fn testcancel() {
-    if current_thread().unwrap_unchecked().wants_cancel.load(Ordering::Acquire) {
+    let this_thread = current_thread().expect("current thread not present");
+
+    if this_thread.has_queued_cancelation.load(Ordering::Acquire) && this_thread.has_enabled_cancelation.load(Ordering::Acquire) {
         cancel_current_thread();
     }
 }
@@ -289,13 +294,66 @@ unsafe fn cancel_current_thread() {
 }
 
 pub unsafe fn cancel(thread: &Pthread) -> Result<(), Errno> {
-    thread.wants_cancel.store(true, Ordering::Release);
+    // TODO: What order should these atomic bools be accessed in?
+    thread.has_queued_cancelation.store(true, Ordering::Release);
 
-    Sys::rlct_kill(thread.os_tid.get().read(), SIGRT_RLCT_CANCEL)?;
+    if thread.has_enabled_cancelation.load(Ordering::Acquire) {
+        Sys::rlct_kill(thread.os_tid.get().read(), SIGRT_RLCT_CANCEL)?;
+    }
 
     Ok(())
 }
 
+pub fn set_sched_param(_thread: &Pthread, _policy: c_int, _param: &sched_param) -> Result<(), Errno> {
+    // TODO
+    Ok(())
+}
+pub fn set_sched_priority(_thread: &Pthread, _prio: c_int) -> Result<(), Errno> {
+    // TODO
+    Ok(())
+}
+pub fn set_cancel_state(state: c_int) -> Result<c_int, Errno> {
+    let this_thread = current_thread().expect("current thread not present");
+
+    let was_cancelable = match state {
+        header::PTHREAD_CANCEL_ENABLE => {
+            let old = this_thread.has_enabled_cancelation.swap(true, Ordering::Release);
+
+            if this_thread.has_queued_cancelation.load(Ordering::Acquire) {
+                unsafe { cancel_current_thread(); }
+            }
+            old
+        },
+        header::PTHREAD_CANCEL_DISABLE => this_thread.has_enabled_cancelation.swap(false, Ordering::Release),
+
+        _ => return Err(Errno(EINVAL)),
+    };
+
+    Ok(match was_cancelable {
+        true => header::PTHREAD_CANCEL_ENABLE,
+        false => header::PTHREAD_CANCEL_DISABLE,
+    })
+}
+pub fn set_cancel_type(ty: c_int) -> Result<c_int, Errno> {
+    let this_thread = current_thread().expect("current thread not present");
+
+    // TODO
+    match ty {
+        header::PTHREAD_CANCEL_DEFERRED => (),
+        header::PTHREAD_CANCEL_ASYNCHRONOUS => (),
+
+        _ => return Err(Errno(EINVAL)),
+    }
+    Ok(header::PTHREAD_CANCEL_DEFERRED)
+}
+pub fn get_cpu_clkid(thread: &Pthread) -> Result<clockid_t, Errno> {
+    // TODO
+    Err(Errno(ENOENT))
+}
+pub fn get_sched_param(thread: &Pthread) -> Result<(clockid_t, sched_param), Errno> {
+    todo!()
+}
+
 // TODO: Hash map?
 // TODO: RwLock to improve perf?
 static OS_TID_TO_PTHREAD: Mutex<BTreeMap<OsTid, ForceSendSync<*mut Pthread>>> = Mutex::new(BTreeMap::new());

src/sync/barrier.rs

@@ -0,0 +1,86 @@
+use core::cmp;
+use core::num::NonZeroU32;
+use core::sync::atomic::{AtomicU32 as AtomicUint, Ordering};
+
+pub struct Barrier {
+    waited_count: AtomicUint,
+    notified_count: AtomicUint,
+    original_count: NonZeroU32,
+}
+
+pub enum WaitResult {
+    Waited,
+    NotifiedAll,
+}
+
+impl Barrier {
+    pub fn new(count: NonZeroU32) -> Self {
+        Self {
+            waited_count: AtomicUint::new(0),
+            notified_count: AtomicUint::new(0),
+            original_count: count,
+        }
+    }
+    pub fn wait(&self) -> WaitResult {
+        // The barrier wait operation can be divided into two parts: (1) incrementing the wait count where
+        // N-1 waiters wait and one notifies the rest, and (2) notifying all threads that have been
+        // waiting.
+
+        let original_count = self.original_count.get();
+
+        loop {
+            let new = self.waited_count.fetch_add(1, Ordering::Acquire) + 1;
+
+            match Ord::cmp(&new, &original_count) {
+                cmp::Ordering::Less => {
+                    // new < original_count, i.e. we were one of the threads that incremented the counter,
+                    // but need to continue waiting for the last waiter to notify the others.
+
+                    loop {
+                        let count = self.waited_count.load(Ordering::Acquire);
+
+                        if count >= original_count { break }
+
+                        let _ = crate::sync::futex_wait(&self.waited_count, count, None);
+                    }
+
+                    // When the required number of threads have called pthread_barrier_wait so waited_count
+                    // >= original_count (should never be able to exceed that value), we can safely reset
+                    // the counter to zero.
+
+                    if self.notified_count.fetch_add(1, Ordering::Relaxed) + 1 >= original_count {
+                        self.waited_count.store(0, Ordering::Relaxed);
+                    }
+
+                    return WaitResult::Waited;
+                }
+                cmp::Ordering::Equal => {
+                    // new == original_count, i.e. we were the one thread doing the last increment, and we
+                    // will be responsible for waking up all other waiters.
+
+                    crate::sync::futex_wake(&self.waited_count, i32::MAX);
+
+                    if self.notified_count.fetch_add(1, Ordering::Relaxed) + 1 >= original_count {
+                        self.waited_count.store(0, Ordering::Relaxed);
+                    }
+
+                    return WaitResult::NotifiedAll;
+                }
+                // FIXME: Starvation?
+                cmp::Ordering::Greater => {
+                    let mut cached = new;
+                    while cached >= original_count {
+                        // new > original_count, i.e. we are waiting on a barrier that is already finished, but
+                        // which has not yet awoken all its waiters and re-initialized the self. The
+                        // simplest way to handle this is to wait for waited_count to return to zero, and
+                        // start over.
+
+                        crate::sync::futex_wait(&self.waited_count, cached, None);
+
+                        cached = self.waited_count.load(Ordering::Acquire);
+                    }
+                }
+            }
+        }
+    }
+}

src/sync/mod.rs

@@ -1,3 +1,4 @@
+pub mod barrier;
 pub mod mutex;
 pub mod once;
 pub mod semaphore;
@@ -15,7 +16,7 @@ use crate::{
 };
 use core::{
     ops::Deref,
-    sync::atomic::{self, AtomicI32 as AtomicInt},
+    sync::atomic::{self, AtomicI32, AtomicU32, AtomicI32 as AtomicInt},
 };
 
 const FUTEX_WAIT: c_int = 0;
@@ -28,19 +29,52 @@ pub enum AttemptStatus {
     Other,
 }
 
-pub unsafe fn futex_wake_ptr(ptr: *mut i32, n: i32) -> usize {
+pub trait FutexTy {
+    fn conv(self) -> i32;
+}
+pub trait FutexAtomicTy {
+    type Ty: FutexTy;
+
+    fn as_mut_ptr(&self) -> *mut Self::Ty;
+}
+impl FutexTy for u32 {
+    fn conv(self) -> i32 {
+        self as i32
+    }
+}
+impl FutexTy for i32 {
+    fn conv(self) -> i32 {
+        self
+    }
+}
+impl FutexAtomicTy for AtomicU32 {
+    type Ty = u32;
+
+    fn as_mut_ptr(&self) -> *mut u32 {
+        AtomicU32::as_mut_ptr(self)
+    }
+}
+impl FutexAtomicTy for AtomicI32 {
+    type Ty = i32;
+
+    fn as_mut_ptr(&self) -> *mut i32 {
+        AtomicI32::as_mut_ptr(self)
+    }
+}
+
+pub unsafe fn futex_wake_ptr(ptr: *mut impl FutexTy, n: i32) -> usize {
     // TODO: unwrap_unchecked?
-    Sys::futex(ptr, FUTEX_WAKE, n, 0).unwrap() as usize
+    Sys::futex(ptr.cast(), FUTEX_WAKE, n, 0).unwrap() as usize
 }
-pub unsafe fn futex_wait_ptr(ptr: *mut i32, value: i32, timeout_opt: Option<&timespec>) -> bool {
+pub unsafe fn futex_wait_ptr<T: FutexTy>(ptr: *mut T, value: T, timeout_opt: Option<&timespec>) -> bool {
     // TODO: unwrap_unchecked?
-    Sys::futex(ptr, FUTEX_WAIT, value, timeout_opt.map_or(0, |t| t as *const _ as usize)) == Ok(0)
+    Sys::futex(ptr.cast(), FUTEX_WAIT, value.conv(), timeout_opt.map_or(0, |t| t as *const _ as usize)) == Ok(0)
 }
-pub fn futex_wake(atomic: &AtomicInt, n: i32) -> usize {
-    unsafe { futex_wake_ptr(atomic.as_ptr(), n) }
+pub fn futex_wake(atomic: &impl FutexAtomicTy, n: i32) -> usize {
+    unsafe { futex_wake_ptr(atomic.as_mut_ptr(), n) }
 }
-pub fn futex_wait(atomic: &AtomicInt, value: i32, timeout_opt: Option<&timespec>) -> bool {
-    unsafe { futex_wait_ptr(atomic.as_ptr(), value, timeout_opt) }
+pub fn futex_wait<T: FutexAtomicTy>(atomic: &T, value: T::Ty, timeout_opt: Option<&timespec>) -> bool {
+    unsafe { futex_wait_ptr(atomic.as_mut_ptr(), value, timeout_opt) }
 }
 pub fn wait_until_generic<F1, F2>(word: &AtomicInt, attempt: F1, mark_long: F2, long: c_int)
 where