diff --git a/ChangeLog b/ChangeLog
index 31c2bc57..f142bcb0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -23,6 +23,7 @@
 - add vips_transpose3d() -- swap major dimensions in a volumetric image
 - remove vips7 stuff from default API ... you must now #include it explicitly
 - acquire an image colormap if none set [jtorresfabra]
+- added vips_argument_get_id() to fix derived classes on win32 [angelmixu]
 
 12/3/18 started 8.6.4
 - better fitting of fonts with overhanging edges [Adrià]
diff --git a/libvips/include/vips/object.h b/libvips/include/vips/object.h
index 1da024fd..3041ea0e 100644
--- a/libvips/include/vips/object.h
+++ b/libvips/include/vips/object.h
@@ -100,8 +100,6 @@ VIPS_ARGUMENT_OPTIONAL_OUTPUT   Eg. the x pos of the image minimum
 	(VIPS_ARGUMENT_OUTPUT | \
 	 VIPS_ARGUMENT_CONSTRUCT)
 
-extern int _vips__argument_id;
-
 #define VIPS_ARG_IMAGE( CLASS, NAME, PRIORITY, LONG, DESC, FLAGS, OFFSET ) { \
 	GParamSpec *pspec; \
 	\
@@ -109,7 +107,7 @@ extern int _vips__argument_id;
 		VIPS_TYPE_IMAGE, \
 		(GParamFlags) (G_PARAM_READWRITE) ); \
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -121,7 +119,7 @@ extern int _vips__argument_id;
 		VIPS_TYPE_INTERPOLATE, \
 		(GParamFlags) (G_PARAM_READWRITE) ); \
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -134,7 +132,7 @@ extern int _vips__argument_id;
 		(VALUE), \
 		(GParamFlags) (G_PARAM_READWRITE) ); \
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -147,7 +145,7 @@ extern int _vips__argument_id;
 		(MIN), (MAX), (VALUE), \
 		(GParamFlags) (G_PARAM_READWRITE) );\
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -160,7 +158,7 @@ extern int _vips__argument_id;
 		(TYPE), \
 		(GParamFlags) (G_PARAM_READWRITE) );\
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -173,7 +171,7 @@ extern int _vips__argument_id;
 		(MIN), (MAX), (VALUE), \
 		(GParamFlags) (G_PARAM_READWRITE) );\
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -186,7 +184,7 @@ extern int _vips__argument_id;
 		(MIN), (MAX), (VALUE), \
 		(GParamFlags) (G_PARAM_READWRITE) );\
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -199,7 +197,7 @@ extern int _vips__argument_id;
 		(TYPE), (VALUE), \
 		(GParamFlags) (G_PARAM_READWRITE) );\
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -212,7 +210,7 @@ extern int _vips__argument_id;
 		(TYPE), (VALUE), \
 		(GParamFlags) (G_PARAM_READWRITE) );\
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -225,7 +223,7 @@ extern int _vips__argument_id;
 		(VALUE), \
 		(GParamFlags) (G_PARAM_READWRITE) ); \
 	g_object_class_install_property( G_OBJECT_CLASS( CLASS ), \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -236,7 +234,7 @@ extern int _vips__argument_id;
 	pspec = g_param_spec_pointer( (NAME), (LONG), (DESC), \
 		(GParamFlags) (G_PARAM_READWRITE) ); \
 	g_object_class_install_property( gobject_class,  \
-		_vips__argument_id++, pspec ); \
+		vips_argument_get_id(), pspec ); \
 	vips_object_class_install_argument( VIPS_OBJECT_CLASS( CLASS ), \
 		pspec, (VipsArgumentFlags) (FLAGS), (PRIORITY), (OFFSET) ); \
 }
@@ -296,6 +294,7 @@ typedef struct _VipsArgumentInstance {
  */
 typedef GHashTable VipsArgumentTable;
 
+int vips_argument_get_id( void );
 void vips__object_set_member( VipsObject *object, GParamSpec *pspec,
 	GObject **member, GObject *argument );
 typedef void *(*VipsArgumentMapFn)( VipsObject *object, GParamSpec *pspec,
diff --git a/libvips/include/vips/private.h b/libvips/include/vips/private.h
index a1be3c42..e28735fc 100644
--- a/libvips/include/vips/private.h
+++ b/libvips/include/vips/private.h
@@ -188,6 +188,10 @@ int vips_region_prepare_many( struct _VipsRegion **reg, const VipsRect *r );
  */
 int vips__view_image( struct _VipsImage *image );
 
+/* Pre 8.7 libvipses used this for allocating argument ids.
+ */
+extern int _vips__argument_id;
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/
diff --git a/libvips/iofuncs/object.c b/libvips/iofuncs/object.c
index 83341daa..911aa7a6 100644
--- a/libvips/iofuncs/object.c
+++ b/libvips/iofuncs/object.c
@@ -1,6 +1,9 @@
 /* abstract base class for all vips objects
  *
  * Edited from nip's base class, 15/10/08
+ *
+ * 29/5/18
+ * 	- added vips_argument_get_id()
  */
 
 /*
@@ -209,6 +212,8 @@ static GMutex *vips__object_all_lock = NULL;
 
 static guint vips_object_signals[SIG_LAST] = { 0 };
 
+/* This has to be externally visible for compatibility with older libvipses.
+ */
 int _vips__argument_id = 1;
 
 /* Keep a cache of nickname -> GType lookups.
@@ -217,6 +222,26 @@ static GHashTable *vips__object_nickname_table = NULL;
 
 G_DEFINE_ABSTRACT_TYPE( VipsObject, vips_object, G_TYPE_OBJECT );
 
+/**
+ * vips_argument_get_id: (skip)
+ *
+ * Allocate a new property id. See g_object_class_install_property().
+ *
+ * Returns: a new property id > 0
+ */
+int 
+vips_argument_get_id( void )
+{
+	int id;
+
+	/* We probably don't need to lock: glib seems to single-thread class
+	 * creation.
+	 */
+	id = _vips__argument_id++;
+
+	return( id );
+}
+
 /* Don't call this directly, see vips_object_build().
  */
 static int