mark lock types with [[nodiscard]]

Reviewed By: dmm-fb Differential Revision: D51439695 fbshipit-source-id: 3422d5c62dcc175a9a35faf33502c46ae54fb32a
facebook · Nov 19, 2023 · b7af40f · b7af40f
1 parent 26a2c02
commit b7af40f
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Showing 2 changed files with 11 additions and 10 deletions.
diff --git a/folly/SharedMutex.h b/folly/SharedMutex.h
@@ -1835,33 +1835,34 @@ class shared_lock<
 
   shared_lock() noexcept = default;
 
-  explicit shared_lock(mutex_type& mutex) : mutex_(std::addressof(mutex)) {
+  FOLLY_NODISCARD explicit shared_lock(mutex_type& mutex)
+      : mutex_(std::addressof(mutex)) {
     lock();
   }
 
   shared_lock(mutex_type& mutex, std::defer_lock_t) noexcept
       : mutex_(std::addressof(mutex)) {}
 
-  shared_lock(mutex_type& mutex, std::try_to_lock_t)
+  FOLLY_NODISCARD shared_lock(mutex_type& mutex, std::try_to_lock_t)
       : mutex_(std::addressof(mutex)) {
     try_lock();
   }
 
-  shared_lock(mutex_type& mutex, std::adopt_lock_t)
+  FOLLY_NODISCARD shared_lock(mutex_type& mutex, std::adopt_lock_t)
       : mutex_(std::addressof(mutex)) {
     token_.state_ = token_type::State::LockedShared;
   }
 
   template <typename Clock, typename Duration>
-  shared_lock(
+  FOLLY_NODISCARD shared_lock(
       mutex_type& mutex,
       const std::chrono::time_point<Clock, Duration>& deadline)
       : mutex_(std::addressof(mutex)) {
     try_lock_until(deadline);
   }
 
   template <typename Rep, typename Period>
-  shared_lock(
+  FOLLY_NODISCARD shared_lock(
       mutex_type& mutex, const std::chrono::duration<Rep, Period>& timeout)
       : mutex_(std::addressof(mutex)) {
     try_lock_for(timeout);

diff --git a/folly/synchronization/Lock.h b/folly/synchronization/Lock.h
@@ -112,7 +112,7 @@ struct lock_storage<Mutex, void> {
   lock_storage(lock_storage&& that) noexcept
       : mutex_{std::exchange(that.mutex_, nullptr)},
         state_{std::exchange(that.state_, false)} {}
-  lock_storage(Mutex& mutex, std::adopt_lock_t)
+  FOLLY_NODISCARD lock_storage(Mutex& mutex, std::adopt_lock_t)
       : mutex_{std::addressof(mutex)}, state_{true} {}
 
   void operator=(lock_storage&&) = delete;
@@ -156,25 +156,25 @@ class lock_base //
   using storage::storage;
   lock_base() = default;
   lock_base(lock_base&&) = default;
-  explicit lock_base(mutex_type& mutex) {
+  FOLLY_NODISCARD explicit lock_base(mutex_type& mutex) {
     storage::mutex_ = std::addressof(mutex);
     lock();
   }
   lock_base(mutex_type& mutex, std::defer_lock_t) noexcept {
     storage::mutex_ = std::addressof(mutex);
   }
-  lock_base(mutex_type& mutex, std::try_to_lock_t) {
+  FOLLY_NODISCARD lock_base(mutex_type& mutex, std::try_to_lock_t) {
     storage::mutex_ = std::addressof(mutex);
     try_lock();
   }
   template <typename Rep, typename Period>
-  lock_base(
+  FOLLY_NODISCARD lock_base(
       mutex_type& mutex, std::chrono::duration<Rep, Period> const& timeout) {
     storage::mutex_ = std::addressof(mutex);
     try_lock_for(timeout);
   }
   template <typename Clock, typename Duration>
-  lock_base(
+  FOLLY_NODISCARD lock_base(
       mutex_type& mutex,
       std::chrono::time_point<Clock, Duration> const& deadline) {
     storage::mutex_ = std::addressof(mutex);