diff --git a/libvips/colour/LabQ2sRGB.c b/libvips/colour/LabQ2sRGB.c
index d0dbc20b..f53e409a 100644
--- a/libvips/colour/LabQ2sRGB.c
+++ b/libvips/colour/LabQ2sRGB.c
@@ -171,8 +171,7 @@ vips_col_make_tables_RGB_8( void )
 {
 	static GOnce once = G_ONCE_INIT;
 
-	if( G_UNLIKELY( once.status != G_ONCE_STATUS_READY ) )
-		(void) g_once( &once, calcul_tables_8, NULL );
+	VIPS_ONCE( &once, calcul_tables_8, NULL ); 
 }
 
 int
@@ -196,8 +195,7 @@ vips_col_make_tables_RGB_16( void )
 {
 	static GOnce once = G_ONCE_INIT;
 
-	if( G_UNLIKELY( once.status != G_ONCE_STATUS_READY ) )
-		(void) g_once( &once, calcul_tables_16, NULL );
+	VIPS_ONCE( &once, calcul_tables_16, NULL ); 
 }
 
 int
@@ -448,7 +446,7 @@ vips_col_make_tables_LabQ2sRGB( void )
 {
 	static GOnce once = G_ONCE_INIT;
 
-	(void) g_once( &once, build_tables, NULL );
+	VIPS_ONCE( &once, build_tables, NULL );
 }
 
 /* Process a buffer of data.
diff --git a/libvips/colour/UCS2LCh.c b/libvips/colour/UCS2LCh.c
index 397861a8..e6b46530 100644
--- a/libvips/colour/UCS2LCh.c
+++ b/libvips/colour/UCS2LCh.c
@@ -228,7 +228,7 @@ vips_col_make_tables_CMC( void )
 {
 	static GOnce once = G_ONCE_INIT;
 
-	(void) g_once( &once, tables_init, NULL );
+	VIPS_ONCE( &once, tables_init, NULL );
 }
 
 /* Process a buffer of data.
diff --git a/libvips/colour/XYZ2Lab.c b/libvips/colour/XYZ2Lab.c
index 14a8b488..d9acebd3 100644
--- a/libvips/colour/XYZ2Lab.c
+++ b/libvips/colour/XYZ2Lab.c
@@ -120,7 +120,7 @@ vips_XYZ2Lab_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 
 	int x;
 
-	(void) g_once( &once, table_init, NULL );
+	VIPS_ONCE( &once, table_init, NULL );
 
 	for( x = 0; x < width; x++ ) {
 		float nX, nY, nZ;
diff --git a/libvips/create/perlin.c b/libvips/create/perlin.c
index 24d0cf1c..5181f365 100644
--- a/libvips/create/perlin.c
+++ b/libvips/create/perlin.c
@@ -284,7 +284,7 @@ vips_perlin_class_init( VipsPerlinClass *class )
 
 	static GOnce once = G_ONCE_INIT;
 
-	(void) g_once( &once, vips_perlin_make_tables, NULL );
+	VIPS_ONCE( &once, vips_perlin_make_tables, NULL );
 
 	gobject_class->set_property = vips_object_set_property;
 	gobject_class->get_property = vips_object_get_property;
diff --git a/libvips/create/text.c b/libvips/create/text.c
index 0c89e295..db27bf75 100644
--- a/libvips/create/text.c
+++ b/libvips/create/text.c
@@ -408,7 +408,7 @@ vips_text_class_init( VipsTextClass *class )
 
 	static GOnce once = G_ONCE_INIT;
 
-	(void) g_once( &once, vips_text_make_lock, NULL );
+	VIPS_ONCE( &once, vips_text_make_lock, NULL );
 
 	gobject_class->dispose = vips_text_dispose;
 	gobject_class->set_property = vips_object_set_property;
diff --git a/libvips/foreign/magick7load.c b/libvips/foreign/magick7load.c
index 1d483483..98e1a753 100644
--- a/libvips/foreign/magick7load.c
+++ b/libvips/foreign/magick7load.c
@@ -293,7 +293,7 @@ vips_foreign_load_magick7_genesis( void )
 {
 	static GOnce once = G_ONCE_INIT;
 
-	(void) g_once( &once, vips_foreign_load_magick7_genesis_cb, NULL );
+	VIPS_ONCE( &once, vips_foreign_load_magick7_genesis_cb, NULL );
 }
 
 static int
diff --git a/libvips/include/vips/util.h b/libvips/include/vips/util.h
index 413be3bf..aa693183 100644
--- a/libvips/include/vips/util.h
+++ b/libvips/include/vips/util.h
@@ -86,6 +86,14 @@ extern "C" {
 #define VIPS_FMIN( A, B ) VIPS_MIN( A, B )
 #endif
 
+/* Testing status before the function call saves a lot of time.
+ */
+#define VIPS_ONCE( ONCE, FUNC, CLIENT ) \
+G_STMT_START { \
+        if( G_UNLIKELY( (ONCE)->status != G_ONCE_STATUS_READY ) ) \
+		(void) g_once( ONCE, FUNC, CLIENT ); \
+} G_STMT_END
+
 /* VIPS_RINT() does "bankers rounding", it rounds to the nerarest even integer.
  * For things like image geometry, we want strict nearest int.
  *
diff --git a/libvips/iofuncs/cache.c b/libvips/iofuncs/cache.c
index a3d70477..bc841a76 100644
--- a/libvips/iofuncs/cache.c
+++ b/libvips/iofuncs/cache.c
@@ -462,7 +462,7 @@ vips__cache_init( void )
 {
 	static GOnce once = G_ONCE_INIT;
 
-	g_once( &once, (GThreadFunc) vips__cache_once_init, NULL );
+	VIPS_ONCE( &once, (GThreadFunc) vips__cache_once_init, NULL );
 }
 
 static void *
diff --git a/libvips/iofuncs/gate.c b/libvips/iofuncs/gate.c
index 84dcbcc2..0b45ec3e 100644
--- a/libvips/iofuncs/gate.c
+++ b/libvips/iofuncs/gate.c
@@ -245,7 +245,7 @@ vips__thread_profile_attach( const char *thread_name )
 
 	VipsThreadProfile *profile;
 
-	g_once( &once, (GThreadFunc) vips__thread_profile_init, NULL );
+	VIPS_ONCE( &once, (GThreadFunc) vips__thread_profile_init, NULL );
 
 	VIPS_DEBUG_MSG( "vips__thread_profile_attach: %s\n", thread_name ); 
 
diff --git a/libvips/iofuncs/memory.c b/libvips/iofuncs/memory.c
index 5d0d92d0..2bebd529 100644
--- a/libvips/iofuncs/memory.c
+++ b/libvips/iofuncs/memory.c
@@ -273,7 +273,7 @@ vips_tracked_init( void )
 {
 	static GOnce vips_tracked_once = G_ONCE_INIT;
 
-	g_once( &vips_tracked_once, 
+	VIPS_ONCE( &vips_tracked_once, 
 		(GThreadFunc) vips_tracked_init_mutex, NULL );
 }
 
diff --git a/libvips/iofuncs/object.c b/libvips/iofuncs/object.c
index 34c13dbb..9f078c55 100644
--- a/libvips/iofuncs/object.c
+++ b/libvips/iofuncs/object.c
@@ -2814,7 +2814,7 @@ vips_type_find( const char *basename, const char *nickname )
 	GType base;
 	GType type;
 
-	g_once( &once, (GThreadFunc) vips_class_build_hash, NULL ); 
+	VIPS_ONCE( &once, (GThreadFunc) vips_class_build_hash, NULL ); 
 
 	hit = (NicknameGType *) 
 		g_hash_table_lookup( vips__object_nickname_table, 
diff --git a/libvips/iofuncs/sinkscreen.c b/libvips/iofuncs/sinkscreen.c
index 82447667..909cc022 100644
--- a/libvips/iofuncs/sinkscreen.c
+++ b/libvips/iofuncs/sinkscreen.c
@@ -1081,7 +1081,7 @@ vips_sink_screen( VipsImage *in, VipsImage *out, VipsImage *mask,
 
 	Render *render;
 
-	g_once( &once, (GThreadFunc) vips_sink_screen_init, NULL );
+	VIPS_ONCE( &once, (GThreadFunc) vips_sink_screen_init, NULL );
 
 	if( tile_width <= 0 || tile_height <= 0 || 
 		max_tiles < -1 ) {