diff --git a/include/gtl/phmap.hpp b/include/gtl/phmap.hpp
index cc5a1a5..468c45e 100644
--- a/include/gtl/phmap.hpp
+++ b/include/gtl/phmap.hpp
@@ -3086,7 +3086,7 @@ class LockableImpl<absl::Mutex> : public AbslMutex {
 //         Microsoft SRWLOCK support (read and write lock support)
 //         use: `phmap::srwlock` instead of `std::mutex`
 // --------------------------------------------------------------------------
-#if defined(_MSVC_LANG) && (defined(SRWLOCK_INIT) || defined(_SYNCHAPI_H_))
+#if defined(_MSC_VER) && (defined(SRWLOCK_INIT) || defined(_SYNCHAPI_H_))
 
 class srwlock {
     SRWLOCK _lock;