diff -r eb491334113f -r 119ac9128c1b src/java.base/windows/native/libnio/ch/IOUtil.c
--- a/src/java.base/windows/native/libnio/ch/IOUtil.c	Fri Oct 25 14:50:16 2019 +0100
+++ b/src/java.base/windows/native/libnio/ch/IOUtil.c	Fri Oct 25 15:56:35 2019 +0100
@@ -192,13 +192,13 @@
 /* Note: This function returns the int fd value from file descriptor.
    It is mostly used for sockets which should use the int fd value.
 */
-jint
+JNIEXPORT jint JNICALL
 fdval(JNIEnv *env, jobject fdo)
 {
     return (*env)->GetIntField(env, fdo, fd_fdID);
 }
 
-void
+JNIEXPORT void JNICALL
 setfdval(JNIEnv *env, jobject fdo, jint val)
 {
     (*env)->SetIntField(env, fdo, fd_fdID, val);