Previous implementation didn't check whether there are pending signals
after return from futex.wait. While it is ok for broadcast case it can
result in multiple wakeups when only one thread is signaled.
This implementation checks that there are pending signals before
returning from wait.
It is similar to the original implementation but the without initial
signal check, here we first go to the futex and then check for pending
signal.
fixes#12877
Current implementation (before this fix) observes number of waiters when
broadcast occurs and then makes that number of wakeups.
If we have multiple threads waiting for wakeup which immediately go into
wait if wakeup is not for that thread (as described in the issue). The
same thread can get multiple wakeups while some got none.
That is not consistent with documented behavior for condition variable
broadcast: `Unblocks all threads currently blocked in a call to wait()
or timedWait() with a given Mutex.`.
This fix ensures that the thread waiting on futext is woken up on futex wake.
* Fix for: DefaultRwLock accumulates write-waiters, eventually fails to write lock #13163
* Comment out debug.print at the end of the last test.
* Code formatting
* - use equality test after lock/unlock rather than peeking into internals.
however, this is still implementation specific and only done for
DefaultRwLock.
- add num_reads maximum to ensure that reader threads stop if writer threads are
starved
- use relaxed orderings for the read atomic counter
- don't check at the end for non-zero read ops, since the reader threads may
only run once if they are starved
* More review changes
- Monotonic is sufficient for incrementing the reads counter
* std: add Thread.Condition.timedWait
I needed the equivalent of `std::condition_variable::wait_for`, but it's missing in std.
This PR adds an implementation, following the status quo of using std.os.CLOCK.REALTIME in the pthread case (i.e. Futex)
A follow-up patch moving futex/condition stuff to monotonic clocks where available seems like a good idea.
This would involve conditionally exposing more functions and constants through std.c and std.os.
For instance, Chromium picks `pthread_cond_timedwait_relative_np` on macOS and `clock_gettime(CLOCK_MONOTONIC...)` on BSD's.
Tested on Windows 11, macOS 12.2.1 and Linux (with/without libc)
* Sleep in the single threaded case, handle timeout overflow in the Windows case and address a race condition in the AtomicCondition case.
Fixes#11353
The renderer treats comments and doc comments differently since doc
comments are parsed into the Ast. This commit adds a check after getting
the text for the doc comment and trims whitespace at the end before
rendering.
The `a = 0,` in the test is here to avoid a ParseError while parsing the
test.
This is a breaking change. Before, usage looked like this:
```zig
const held = mutex.acquire();
defer held.release();
```
Now it looks like this:
```zig
mutex.lock();
defer mutex.unlock();
```
The `Held` type was an idea to make mutexes slightly safer by making it
more difficult to forget to release an aquired lock. However, this
ultimately caused more problems than it solved, when any data structures
needed to store a held mutex. Simplify everything by reducing the API
down to the primitives: lock() and unlock().
Closes#8051Closes#8246Closes#10105
* std lib tests are passing on x86_64-linux with and without -lc
* stage2 is building from source on x86_64-linux
* down to 38 remaining uses of `usingnamespace`
The main purpose of this branch is to explore avoiding the
`usingnamespace` feature of the zig language, specifically with regards
to `std.os` and related functionality.
If this experiment is successful, it will provide a data point on
whether or not it would be practical to entirely remove `usingnamespace`
from the language.
In this commit, `usingnamespace` has been completely eliminated from
the Linux x86_64 compilation path, aside from io_uring.
The behavior tests pass, however that's as far as this branch goes. It is
very breaking, and a lot more work is needed before it could be
considered mergeable. I wanted to put a pull requset up early so that
zig programmers have time to provide feedback.
This is progress towards closing #6600 since it clarifies where the
actual "owner" of each declaration is, and reduces the number of
different ways to import the same declarations.
One of the main organizational strategies used here is to do namespacing
with real namespaces (e.g. structs) rather than by having declarations
share a common prefix (the C strategy). It's no coincidence that
`usingnamespace` has similar semantics to `#include` and becomes much
less necessary when using proper namespaces.
We already have a LICENSE file that covers the Zig Standard Library. We
no longer need to remind everyone that the license is MIT in every single
file.
Previously this was introduced to clarify the situation for a fork of
Zig that made Zig's LICENSE file harder to find, and replaced it with
their own license that required annual payments to their company.
However that fork now appears to be dead. So there is no need to
reinforce the copyright notice in every single file.
The primary purpose of this change is to eliminate one usage of
`usingnamespace` in the standard library - specifically the usage for
errno values in `std.os.linux`.
This is accomplished by truncating the `E` prefix from error values, and
making errno a proper enum.
A similar strategy can be used to eliminate some other `usingnamespace`
sites in the std lib.
- deprecates `std.Thread.spinLoopHint` and moves it to `std.atomic.spinLoopHint`
- added an Atomic(T) generic wrapper type which replaces atomic.Bool and atomic.Int
- in Atomic(T), selectively expose member functions depending on T and include bitwise atomic methods when T is an Integer
- added fence() and compilerFence() to std.atomic
Conflicts:
* doc/langref.html.in
* lib/std/enums.zig
* lib/std/fmt.zig
* lib/std/hash/auto_hash.zig
* lib/std/math.zig
* lib/std/mem.zig
* lib/std/meta.zig
* test/behavior/alignof.zig
* test/behavior/bitcast.zig
* test/behavior/bugs/1421.zig
* test/behavior/cast.zig
* test/behavior/ptrcast.zig
* test/behavior/type_info.zig
* test/behavior/vector.zig
Master branch added `try` to a bunch of testing function calls, and some
lines also had changed how to refer to the native architecture and other
`@import("builtin")` stuff.
Beside the new order being consistent with the ThreadPool API and making
more sense, this shuffling allows to write the context argument type in
terms of the startFn arguments, reducing the use of anytype (eg. less
explicit casts when using comptime_int parameters, yay).
Sorry for the breakage.
Closes#8082
