diff options
Diffstat (limited to 'absl/base/thread_annotations.h')
| -rw-r--r-- | absl/base/thread_annotations.h | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/absl/base/thread_annotations.h b/absl/base/thread_annotations.h index 8d30b932..2241ace4 100644 --- a/absl/base/thread_annotations.h +++ b/absl/base/thread_annotations.h @@ -31,7 +31,6 @@ // that evaluate to a concrete mutex object whenever possible. If the mutex // you want to refer to is not in scope, you may use a member pointer // (e.g. &MyClass::mutex_) to refer to a mutex in some (unknown) object. -// #ifndef ABSL_BASE_THREAD_ANNOTATIONS_H_ #define ABSL_BASE_THREAD_ANNOTATIONS_H_ @@ -109,13 +108,23 @@ // The mutex is expected to be held both on entry to, and exit from, the // function. // +// An exclusive lock allows read-write access to the guarded data member(s), and +// only one thread can acquire a lock exclusively at any one time. A shared lock +// allows read-only access, and any number of threads can acquire a shared lock +// concurrently. +// +// Generally, non-const methods should be annotated with +// EXCLUSIVE_LOCKS_REQUIRED, while const methods should be annotated with +// SHARED_LOCKS_REQUIRED. +// // Example: // // Mutex mu1, mu2; // int a GUARDED_BY(mu1); // int b GUARDED_BY(mu2); // -// void foo() EXCLUSIVE_LOCKS_REQUIRED(mu1, mu2) { ... }; +// void foo() EXCLUSIVE_LOCKS_REQUIRED(mu1, mu2) { ... } +// void bar() const SHARED_LOCKS_REQUIRED(mu1, mu2) { ... } #define EXCLUSIVE_LOCKS_REQUIRED(...) \ THREAD_ANNOTATION_ATTRIBUTE__(exclusive_locks_required(__VA_ARGS__)) |