diff --git a/sim_disk.c b/sim_disk.c
index 6edee1c4..926b9252 100644
--- a/sim_disk.c
+++ b/sim_disk.c
@@ -1674,6 +1674,15 @@ errno = EINVAL;
 #else
 #include <winioctl.h>
 #endif
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+WINBASEAPI BOOL WINAPI GetFileSizeEx(HANDLE hFile, PLARGE_INTEGER lpFileSize);
+#if defined(__cplusplus)
+    }
+#endif
+
 struct _device_type {
     int32 Type;
     const char *desc;
@@ -1817,8 +1826,6 @@ static void sim_os_disk_flush_raw (FILE *f)
 FlushFileBuffers ((HANDLE)f);
 }
 
-extern WINBASEAPI BOOL WINAPI GetFileSizeEx(HANDLE hFile, PLARGE_INTEGER lpFileSize);
-
 static t_offset sim_os_disk_size_raw (FILE *Disk)
 {
 DWORD IoctlReturnSize;