build: keep Windows building on VS2019. #2145

nedbat · nedbat · commit 3019e369b4e1 · 2026-03-13T06:59:11.000-04:00
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -31,9 +31,13 @@ Unreleased
   cause a problem, but now it's done properly, thanks to `Ellie Ayla
   <pull 2142_>`_.
 
+- Fix: the C extension wouldn't build on VS2019, but now it does (`issue
+  2145`_).
+
 .. _issue 2138: https://github.com/coveragepy/coveragepy/issues/2138
 .. _issue 2141: https://github.com/coveragepy/coveragepy/issues/2141
 .. _pull 2142: https://github.com/coveragepy/coveragepy/pull/2142
+.. _issue 2145: https://github.com/coveragepy/coveragepy/issues/2145
 
 .. start-releases
 
diff --git a/coverage/ctracer/util.h b/coverage/ctracer/util.h
@@ -5,7 +5,14 @@
 #define _COVERAGE_UTIL_H
 
 #include <Python.h>
+
+#if defined(_MSC_VER) && _MSC_VER < 1939
+#define _Atomic volatile
+#define atomic_load(p) (*(p))
+#define atomic_store(p, v) _InterlockedExchange((p), (v))
+#else
 #include <stdatomic.h>
+#endif
 
 /* Compile-time debugging helpers */
 #undef WHAT_LOG         /* Define to log the WHAT params in the trace function. */
