diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 356fcc6..78545da 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -143,7 +143,7 @@ do { \
 /*
  * from utils/init/globals.c
  */
-extern pid_t PostmasterPid;
+extern PGDLLIMPORT pid_t PostmasterPid;
 extern bool IsPostmasterEnvironment;
 extern PGDLLIMPORT bool IsUnderPostmaster;
 extern bool IsBackgroundWorker;