| Issue |
76807
|
| Summary |
[libc++] Hangs in std::condition_variable_any when used with std::stop_token
|
| Labels |
libc++
|
| Assignees |
|
| Reporter |
alexbatashev
|
The following piece of code appears to work reliably and correctly (or at least the way that I expect it to work) with `libstdc++`, but sporadically hangs with the latest `libc++`:
```c++
#include <thread>
#include <stop_token>
#include <mutex>
#include <condition_variable>
#include <iostream>
class thread {
public:
thread() {
thread_ = std::jthread([this](std::stop_token st) {
while (!st.stop_requested()) {
std::unique_lock lock{m_};
cv_.wait(lock, st, []{ return false; });
}
});
}
private:
std::mutex m_;
std::condition_variable_any cv_;
std::jthread thread_;
};
int main() {
thread t;
#ifdef _LIBCPP_VERSION
std::cout << "libc++\n";
#else
std::cout << "libstdc++\n";
#endif
}
```
Results with `libstdc++` and Clang 18. The process exits almost immediately with exit code 0.
`libc++` with Clang 18 commit d933b88b71b00461815667d7cd0bb2fecd8606db. Sometimes it works fine, but sometimes it would hang forever until the process is killed from outside.
I also tested with commit 7e186d366d6c7def0543acc255931f617e76dff0 with the same result.
https://godbolt.org/z/hjTheTnon
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