[libcxx-commits] [libcxx] [libc++] debug semaaphore (PR #180353)

[via libcxx-commits]

https://github.com/huixie90 created https://github.com/llvm/llvm-project/pull/180353

None

>From 79cc6e2cc0b253b0a34a3b5ad302341fa943170b Mon Sep 17 00:00:00 2001
From: Hui Xie <hui.xie1990 at gmail.com>
Date: Sat, 7 Feb 2026 16:19:16 +0000
Subject: [PATCH] [libc++] debug semaaphore

---
 .../thread.semaphore/timed.debug.pass.cpp     | 84 +++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp

diff --git a/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
new file mode 100644
index 0000000000000..d7833194927e4
--- /dev/null
+++ b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
@@ -0,0 +1,84 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: no-threads
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <semaphore>
+
+#include <semaphore>
+#include <thread>
+#include <chrono>
+#include <cassert>
+#include <iostream>
+#include <iomanip>
+
+
+#include "make_test_thread.h"
+#include "test_macros.h"
+
+int main(int, char**)
+{
+  auto const start = std::chrono::steady_clock::now();
+  auto log = [start] ()-> auto& {
+    using namespace std::chrono;
+
+    auto elapsed = steady_clock::now() - start;
+
+    auto hours = duration_cast<std::chrono::hours>(elapsed);
+    elapsed -= hours;
+
+    auto minutes = duration_cast<std::chrono::minutes>(elapsed);
+    elapsed -= minutes;
+
+    auto seconds = duration_cast<std::chrono::seconds>(elapsed);
+    elapsed -= seconds;
+
+    auto milliseconds = duration_cast<std::chrono::milliseconds>(elapsed);
+
+    std::cerr << "["
+              << std::setw(2) << std::setfill('0') << hours.count() << ":"
+              << std::setw(2) << std::setfill('0') << minutes.count() << ":"
+              << std::setw(2) << std::setfill('0') << seconds.count() << "."
+              << std::setw(3) << std::setfill('0') << milliseconds.count()
+              << "] ";
+
+    return std::cerr;
+  };
+
+  std::counting_semaphore<> s(0);
+
+  log() << "try_acquire_until: start + " <<  std::chrono::milliseconds(250)  << "\n";
+  assert(!s.try_acquire_until(start + std::chrono::milliseconds(250)));
+  log() << "done: try_acquire_until: start + " <<  std::chrono::milliseconds(250)  << "\n";
+
+  log() << "try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
+  assert(!s.try_acquire_for(std::chrono::milliseconds(250)));
+  log() << "done: try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
+
+  std::thread t = support::make_test_thread([&](){
+    std::this_thread::sleep_for(std::chrono::milliseconds(250));
+    s.release();
+    std::this_thread::sleep_for(std::chrono::milliseconds(250));
+    s.release();
+  });
+
+  log() << "try_acquire_until: start + " <<  std::chrono::seconds(2)  << "\n";
+  assert(s.try_acquire_until(start + std::chrono::seconds(2)));
+  log() << "done: try_acquire_until: start + " <<  std::chrono::seconds(2)  << "\n";
+
+  log() << "try_acquire_for: " << std::chrono::seconds(2) << "\n";
+  assert(s.try_acquire_for(std::chrono::seconds(2)));
+  log() << "done: try_acquire_for: " << std::chrono::seconds(2) << "\n";
+  t.join();
+
+  auto const end = std::chrono::steady_clock::now();
+  assert(end - start < std::chrono::seconds(10));
+
+  return 1;
+}