1//===-- Implementation of the Rwlock's clockrdlock function ---------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "src/pthread/pthread_rwlock_clockrdlock.h"
10
11#include "hdr/errno_macros.h"
12#include "src/__support/common.h"
13#include "src/__support/macros/config.h"
14#include "src/__support/threads/linux/rwlock.h"
15
16#include <pthread.h>
17
18namespace LIBC_NAMESPACE_DECL {
19
20static_assert(
21 sizeof(RwLock) == sizeof(pthread_rwlock_t) &&
22 alignof(RwLock) == alignof(pthread_rwlock_t),
23 "The public pthread_rwlock_t type must be of the same size and alignment "
24 "as the internal rwlock type.");
25
26LLVM_LIBC_FUNCTION(int, pthread_rwlock_clockrdlock,
27 (pthread_rwlock_t * rwlock, clockid_t clockid,
28 const timespec *abstime)) {
29 if (!rwlock)
30 return EINVAL;
31 if (clockid != CLOCK_MONOTONIC && clockid != CLOCK_REALTIME)
32 return EINVAL;
33 bool is_realtime = (clockid == CLOCK_REALTIME);
34 RwLock *rw = reinterpret_cast<RwLock *>(rwlock);
35 LIBC_ASSERT(abstime && "clockrdlock called with a null timeout");
36 auto timeout = internal::AbsTimeout::from_timespec(
37 *abstime, /*is_realtime=*/is_realtime);
38 if (LIBC_LIKELY(timeout.has_value()))
39 return static_cast<int>(rw->read_lock(timeout.value()));
40
41 switch (timeout.error()) {
42 case internal::AbsTimeout::Error::Invalid:
43 return EINVAL;
44 case internal::AbsTimeout::Error::BeforeEpoch:
45 return ETIMEDOUT;
46 }
47 __builtin_unreachable();
48}
49
50} // namespace LIBC_NAMESPACE_DECL
51

source code of libc/src/pthread/pthread_rwlock_clockrdlock.cpp