fixes for rsutils event.h

Author: maloel

third-party/rsutils/include/rsutils/concurrency/event.h

@@ -1,5 +1,5 @@
 // License: Apache 2.0. See LICENSE file in root directory.
-// Copyright(c) 2024 Intel Corporation. All Rights Reserved.
+// Copyright(c) 2025 Intel Corporation. All Rights Reserved.
 #pragma once
 
 #include <chrono>
@@ -20,8 +20,8 @@ class event
     bool _is_set;
 
 public:
-    event()
-        : _is_set( false )
+    event( bool is_set = false )
+        : _is_set( is_set )
     {
     }
 
@@ -47,16 +47,19 @@ class event
 
     // Untrigger the event
     // Does not affect any threads
-    void clear()
+    // Returns the previous state
+    bool clear()
     {
         std::unique_lock< std::mutex > lock( _m );
+        bool was_set = _is_set;
         _is_set = false;
+        return was_set;
     }
 
     // Block until the event is set()
     // If already set, returns immediately
     // The event remains set when returning: it needs to be cleared...
-    void wait() const
+    void wait()
     {
         std::unique_lock< std::mutex > lock( _m );
         if( ! _is_set )
@@ -75,11 +78,11 @@ class event
     // If already set, returns immediately
     // Returns true unless a timeout occurred
     template< class Rep, class Period >
-    bool wait( std::chrono::duration< Rep, Period > const & timeout ) const
+    bool wait( std::chrono::duration< Rep, Period > const & timeout )
     {
         std::unique_lock< std::mutex > lock( _m );
         if( ! _is_set )
-            _is_set = ( std::cv_status::timeout != _cv.wait( lock, timeout ) );
+            _is_set = ( std::cv_status::timeout != _cv.wait_for( lock, timeout ) );
         return _is_set;
     }
 
@@ -90,7 +93,7 @@ class event
     {
         std::unique_lock< std::mutex > lock( _m );
         _is_set = false;
-        _is_set = ( std::cv_status::timeout != _cv.wait( lock, timeout ) );
+        _is_set = ( std::cv_status::timeout != _cv.wait_for( lock, timeout ) );
         return _is_set;
     }
 };