[libc-commits] [libc] [libc][Semaphore] Add public sem_t type and entry (PR #213489)

[Jeff Bailey via libc-commits]

================
@@ -0,0 +1,33 @@
+//===-- Linux implementation of sem_init ----------------------------------===//
+//
+// 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 "src/semaphore/sem_init.h"
+
+#include "hdr/errno_macros.h"
+#include "hdr/limits_macros.h"
+#include "hdr/types/sem_t.h"
+#include "src/__support/CPP/new.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+#include "src/semaphore/linux/semaphore.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
----------------
kaladron wrote:

To ensure the Semaphore and sem_t types align, something like this should be in here:

```c++
static_assert(sizeof(Semaphore) == sizeof(sem_t) &&
              alignof(Semaphore) == alignof(sem_t),
              "Semaphore and sem_t size/alignment mismatch");
static_assert(offsetof(Semaphore, value) == offsetof(sem_t, __value),
              "value field offset mismatch");
static_assert(offsetof(Semaphore, canary) == offsetof(sem_t, __canary),
              "canary field offset mismatch");
static_assert(offsetof(Semaphore, is_shared) == offsetof(sem_t, __is_shared),
              "is_shared field offset mismatch");
```

https://github.com/llvm/llvm-project/pull/213489