[libc-commits] [libc] [libc] add posix_mutex_trylock support (PR #191531)

[Alexey Samsonov via libc-commits]

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@@ -0,0 +1,26 @@
+//===-- Linux implementation of the pthread_mutex_trylock function --------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutex_trylock.h"
+
+#include "hdr/errno_macros.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/threads/mutex.h"
+#include "src/__support/threads/mutex_common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+// The implementation currently handles only plain mutexes.
+LLVM_LIBC_FUNCTION(int, pthread_mutex_trylock, (pthread_mutex_t * mutex)) {
+  if (reinterpret_cast<Mutex *>(mutex)->try_lock() == MutexError::BUSY)
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vonosmas wrote:

Right, I mean that `try_lock` method is present in `unix_mutex` variant, but not in generic "Mutex" declared in libc/src/__support/threads/mutex.h for LIBC_THREAD_MODE_SINGLE (i.e. there's no stub for try_lock method there). Also, the API in the comment https://github.com/llvm/llvm-project/blob/121f5a96ff38ec0c5d5f7274b1b0ca0df26a1cee/libc/src/__support/threads/mutex.h#L21-L28 is incorrect.

This is not the blocker for this PR, but I figured you might clean up try_lock references in the same commit, as an option.

https://github.com/llvm/llvm-project/pull/191531