diff -r eb491334113f -r 119ac9128c1b src/java.base/windows/native/libnio/ch/nio_util.h
--- a/src/java.base/windows/native/libnio/ch/nio_util.h	Fri Oct 25 14:50:16 2019 +0100
+++ b/src/java.base/windows/native/libnio/ch/nio_util.h	Fri Oct 25 15:56:35 2019 +0100
@@ -35,13 +35,16 @@
  */
 #define MAX_BUFFER_SIZE             ((128*1024)-1)
 
-jint fdval(JNIEnv *env, jobject fdo);
-void setfdval(JNIEnv *env, jobject fdo, jint val);
+JNIEXPORT jint JNICALL
+fdval(JNIEnv *env, jobject fdo);
+JNIEXPORT void JNICALL
+setfdval(JNIEnv *env, jobject fdo, jint val);
 jlong handleval(JNIEnv *env, jobject fdo);
 jint convertReturnVal(JNIEnv *env, jint n, jboolean r);
 jlong convertLongReturnVal(JNIEnv *env, jlong n, jboolean r);
 jboolean purgeOutstandingICMP(JNIEnv *env, jclass clazz, jint fd);
-jint handleSocketError(JNIEnv *env, int errorValue);
+JNIEXPORT jint JNICALL
+handleSocketError(JNIEnv *env, int errorValue);
 
 #ifdef _WIN64