diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 155d8519a74..4f99f701ea5 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -3734,13 +3734,24 @@ write_stderr(const char *fmt,...)
 {
 	va_list		ap;
 
+	va_start(ap, fmt);
+	vwrite_stderr(fmt, ap);
+	va_end(ap);
+}
+
+
+/*
+ * Write errors to stderr (or by equal means when stderr is
+ * not available) - va_list version
+ */
+void
+vwrite_stderr(const char *fmt, va_list ap)
+{
 #ifdef WIN32
 	char		errbuf[2048];	/* Arbitrary size? */
 #endif
 
 	fmt = _(fmt);
-
-	va_start(ap, fmt);
 #ifndef WIN32
 	/* On Unix, we just fprintf to stderr */
 	vfprintf(stderr, fmt, ap);
@@ -3763,7 +3774,6 @@ write_stderr(const char *fmt,...)
 		fflush(stderr);
 	}
 #endif
-	va_end(ap);
 }
 
 
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 8bb55e5b3cc..b3e95044174 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -536,6 +536,7 @@ extern void write_jsonlog(ErrorData *edata);
  * safely (memory context, GUC load etc)
  */
 extern void write_stderr(const char *fmt,...) pg_attribute_printf(1, 2);
+extern void vwrite_stderr(const char *fmt, va_list ap) pg_attribute_printf(1, 0);
 
 /*
  * Write a message to STDERR using only async-signal-safe functions.  This can
diff --git a/src/port/win32security.c b/src/port/win32security.c
index 4d9d28c0d7f..346d86e6f88 100644
--- a/src/port/win32security.c
+++ b/src/port/win32security.c
@@ -31,9 +31,9 @@ log_error(const char *fmt,...)
 
 	va_start(ap, fmt);
 #ifndef FRONTEND
-	write_stderr(fmt, ap);
+	vwrite_stderr(fmt, ap);
 #else
-	fprintf(stderr, fmt, ap);
+	vfprintf(stderr, fmt, ap);
 #endif
 	va_end(ap);
 }