fix(Mutex): C++ 20 does not guarantee atomic_flag.test #5352 (#5353)

aleks-f · web-flow · commit 20b1ea939ed2 · 2026-05-15T16:13:14.000+02:00
diff --git a/Foundation/src/Mutex.cpp b/Foundation/src/Mutex.cpp
@@ -66,7 +66,7 @@ namespace {
 // to avoid cache line bouncing, then attempts acquire if lock appears free.
 inline bool tryAcquire(std::atomic_flag& flag)
 {
-#if POCO_HAVE_CPP20_COMPILER
+#if defined(__cpp_lib_atomic_flag_test)
 	if (!flag.test(std::memory_order_relaxed))
 		if (!flag.test_and_set(std::memory_order_acquire))
 			return true;

Original file line number	Diff line number	Diff line change
`@@ -66,7 +66,7 @@ namespace {`
`66`	`66`	`// to avoid cache line bouncing, then attempts acquire if lock appears free.`
`67`	`67`	`inline bool tryAcquire(std::atomic_flag& flag)`
`68`	`68`	`{`
`69`		`-#if POCO_HAVE_CPP20_COMPILER`
	`69`	`+#if defined(__cpp_lib_atomic_flag_test)`
`70`	`70`	`if (!flag.test(std::memory_order_relaxed))`
`71`	`71`	`if (!flag.test_and_set(std::memory_order_acquire))`
`72`	`72`	`return true;`