diff --git a/include/log4cplus/helpers/eventcounter.h b/include/log4cplus/helpers/eventcounter.h
index be9f192fb..f305de26d 100644
--- a/include/log4cplus/helpers/eventcounter.h
+++ b/include/log4cplus/helpers/eventcounter.h
@@ -32,6 +32,7 @@
 #pragma once
 #endif
 
+#include <log4cplus/internal/threadsafetyanalysis.h>
 #include <log4cplus/thread/syncprims.h>
 #include <cstddef>
 #include <atomic>
@@ -78,9 +79,9 @@ class LOG4CPLUS_EXPORT SteadyClockGate
 
 private:
     log4cplus::thread::SimpleMutex mtx;
-    Duration const pause_duration;
-    TimePoint timeout_point;
-    TimePoint prev_timeout_point;
+    Duration const pause_duration LOG4CPLUS_TSA_GUARDED_BY (mtx);
+    TimePoint timeout_point LOG4CPLUS_TSA_GUARDED_BY (mtx);
+    TimePoint prev_timeout_point LOG4CPLUS_TSA_GUARDED_BY (mtx);
 };
 
 
diff --git a/include/log4cplus/loggingmacros.h b/include/log4cplus/loggingmacros.h
index b5826ea70..dc2131d58 100644
--- a/include/log4cplus/loggingmacros.h
+++ b/include/log4cplus/loggingmacros.h
@@ -530,9 +530,8 @@ LOG4CPLUS_EXPORT void macro_forced_log (log4cplus::Logger const &,
 //! Helper macro for LOG4CPLUS_ASSERT() macro.
 #define LOG4CPLUS_ASSERT_STRINGIFY(X) #X
 
-//! If the condition given in second parameter evaluates false, this
-//! macro logs it using FATAL log level, including the condition's
-//! source text.
+//! If the `condition` evaluates false, this macro logs it using FATAL
+//! log level, including the `condition`'s source text.
 #define LOG4CPLUS_ASSERT(logger, condition)                             \
     LOG4CPLUS_SUPPRESS_DOWHILE_WARNING()                                \
     do {                                                                \
@@ -544,5 +543,28 @@ LOG4CPLUS_EXPORT void macro_forced_log (log4cplus::Logger const &,
     } while (false)                                                     \
     LOG4CPLUS_RESTORE_DOWHILE_WARNING()
 
+//! If the `condition` evaluates false, this macro logs a message
+//! formatted from `printf` format string passed in 3rd and remaining
+//! arguments.
+#define LOG4CPLUS_ASSERT_FMT(logger, condition, ...)                    \
+    LOG4CPLUS_SUPPRESS_DOWHILE_WARNING()                                \
+    do {                                                                \
+        if (! (condition)) [[unlikely]] {                               \
+            LOG4CPLUS_FATAL_FMT ((logger), __VA_ARGS__);                \
+        }                                                               \
+    } while (false)                                                     \
+    LOG4CPLUS_RESTORE_DOWHILE_WARNING()
+
+//! If the `condition` evaluates false, this macro logs a message
+//! formatted from `std::format` format string passed in 3rd and remaining
+//! arguments.
+#define LOG4CPLUS_ASSERT_FORMAT(logger, condition, ...)                 \
+    LOG4CPLUS_SUPPRESS_DOWHILE_WARNING()                                \
+    do {                                                                \
+        if (! (condition)) [[unlikely]] {                               \
+            LOG4CPLUS_FATAL_FORMAT ((logger), __VA_ARGS__);             \
+        }                                                               \
+    } while (false)                                                     \
+    LOG4CPLUS_RESTORE_DOWHILE_WARNING()
 
 #endif /* LOG4CPLUS_LOGGING_MACROS_HEADER_ */