diff --git a/ChangeLog b/ChangeLog
index 9e61a2ed..6775368f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -17,6 +17,9 @@
 - add "mode" param to vips_draw_image()
 - add vips_hough_circle()
 - reduce default cache size to 1,000 operations
+- added "postbuild" signal
+- vips_system() now supports many input images and you can change image
+  argument order
 
 6/3/14 started 7.38.6
 - grey ramp minimum was wrong
diff --git a/TODO b/TODO
index 25e74a51..523113c2 100644
--- a/TODO
+++ b/TODO
@@ -1,7 +1,25 @@
+- try:
+
+	$ vips system "vips add %s %s %s" --in "k2.jpg k4.jpg" \
+		--out-format "%s.tif" --out x.v --log
+	memory: high-water mark 9.37 MB
+	""
+	memory: high-water mark 27.89 MB
+	$
+
+  but x.v does not appear
+
+- can we use postbuild elsewhere? look at use of "preclose" / "written", etc. 
+
+
+
+
 - why is cache in nip2 so slow? its awful
 
   investigate again
 
+  is it using vips_sinkscreen()? should it use tilecache?
+
 
 - test draw_mask on labq images
 
diff --git a/libvips/conversion/bandjoin.c b/libvips/conversion/bandjoin.c
index 42fe4cba..fb724711 100644
--- a/libvips/conversion/bandjoin.c
+++ b/libvips/conversion/bandjoin.c
@@ -78,7 +78,7 @@ typedef struct _VipsBandjoin {
 
 	/* The input images.
 	 */
-	VipsArea *in;
+	VipsArrayImage *in;
 } VipsBandjoin;
 
 typedef VipsBandaryClass VipsBandjoinClass;
diff --git a/libvips/deprecated/vips7compat.c b/libvips/deprecated/vips7compat.c
index be351172..79be5833 100644
--- a/libvips/deprecated/vips7compat.c
+++ b/libvips/deprecated/vips7compat.c
@@ -1754,14 +1754,24 @@ im_text( IMAGE *out, const char *text, const char *font,
 int 
 im_system( VipsImage *im, const char *cmd, char **out )
 {
+	VipsArea *area;
+	VipsImage **array;
 	char *str;
 
+	area = vips_area_new_array_object( 1 );
+	array = (VipsImage **) area->data;
+	array[0] = im;
+
 	if( vips_system( cmd, 
-		"in", im,
+		"in", area,
 		"in_format", "%s.v",
 		"log", &str,
-		NULL ) )
+		NULL ) ) {
+		vips_area_unref( area );
 		return( -1 );
+	}
+
+	vips_area_unref( area );
 
 	if( out )
 		*out = str;
@@ -1774,17 +1784,27 @@ im_system_image( VipsImage *im,
 	const char *in_format, const char *out_format, const char *cmd_format,
 	char **log )
 {
+	VipsArea *area;
+	VipsImage **array;
 	char *str;
 	VipsImage *out; 
 
+	area = vips_area_new_array_object( 1 );
+	array = (VipsImage **) area->data;
+	array[0] = im;
+
 	if( vips_system( cmd_format, 
-		"in", im,
+		"in", area,
 		"out", &out,
 		"in_format", in_format,
 		"out_format", out_format,
 		"log", &str,
-		NULL ) )
+		NULL ) ) {
+		vips_area_unref( area );
 		return( NULL );
+	}
+
+	vips_area_unref( area );
 
 	if( log )
 		*log = str;
diff --git a/libvips/include/vips/internal.h b/libvips/include/vips/internal.h
index acf80275..6baae9ce 100644
--- a/libvips/include/vips/internal.h
+++ b/libvips/include/vips/internal.h
@@ -307,6 +307,7 @@ void vips_convolution_operation_init( void );
 void vips_draw_operation_init( void );
 
 guint64 vips__parse_size( const char *size_string );
+int vips__substitute( const char *domain, char *buf, size_t len, char *sub );
 
 IMAGE *vips__deprecated_open_read( const char *filename, gboolean sequential );
 IMAGE *vips__deprecated_open_write( const char *filename );
diff --git a/libvips/include/vips/object.h b/libvips/include/vips/object.h
index 13274b57..a23af7ec 100644
--- a/libvips/include/vips/object.h
+++ b/libvips/include/vips/object.h
@@ -445,6 +445,10 @@ struct _VipsObjectClass {
 	 */
 	int (*build)( VipsObject *object );
 
+	/* Just after build ... the object is fully ready for work. 
+	 */
+	int (*postbuild)( VipsObject *object );
+
 	/* Try to print something about the class, handy for help displays.
 	 * Keep to one line.
 	 */
diff --git a/libvips/include/vips/type.h b/libvips/include/vips/type.h
index 1d6abb9b..77fefada 100644
--- a/libvips/include/vips/type.h
+++ b/libvips/include/vips/type.h
@@ -162,6 +162,7 @@ GType vips_array_int_get_type( void );
  * The #GType for a #VipsArrayImage.
  */
 #define VIPS_TYPE_ARRAY_IMAGE (vips_array_image_get_type())
+typedef VipsArea VipsArrayImage;
 GType vips_array_image_get_type( void );
 
 void vips_value_set_area( GValue *value, VipsCallbackFn free_fn, void *data );
diff --git a/libvips/iofuncs/Makefile.am b/libvips/iofuncs/Makefile.am
index af1af54b..e0869892 100644
--- a/libvips/iofuncs/Makefile.am
+++ b/libvips/iofuncs/Makefile.am
@@ -1,6 +1,8 @@
 noinst_LTLIBRARIES = libiofuncs.la
 
 libiofuncs_la_SOURCES = \
+	vipsmarshal.h \
+	vipsmarshal.c \
 	type.c \
 	gate.c \
 	enumtypes.c \
@@ -33,7 +35,17 @@ libiofuncs_la_SOURCES = \
 	system.c \
 	buffer.c 
 
-EXTRA_DIST = enumtemplate
+vipsmarshal.h:
+	glib-genmarshal --prefix=vips --header vipsmarshal.list > vipsmarshal.h
+vipsmarshal.c:
+	echo "#include \"vipsmarshal.h\"" > vipsmarshal.c 
+	glib-genmarshal --prefix=vips --body vipsmarshal.list >> vipsmarshal.c
+
+EXTRA_DIST = \
+	enumtemplate \
+	vipsmarshal.h \
+	vipsmarshal.c \
+	vipsmarshal.list
 
 AM_CPPFLAGS = -I${top_srcdir}/libvips/include @VIPS_CFLAGS@ @VIPS_INCLUDES@ 
 
diff --git a/libvips/iofuncs/object.c b/libvips/iofuncs/object.c
index 62e7fb4c..dd07472c 100644
--- a/libvips/iofuncs/object.c
+++ b/libvips/iofuncs/object.c
@@ -52,6 +52,8 @@
 
 #include <gobject/gvaluecollector.h>
 
+#include "vipsmarshal.h"
+
 /**
  * SECTION: object
  * @short_description: the VIPS base object class
@@ -111,6 +113,7 @@
 /* Our signals. 
  */
 enum {
+	SIG_POSTBUILD,		
 	SIG_PRECLOSE,		
 	SIG_CLOSE,		
 	SIG_POSTCLOSE,		
@@ -132,6 +135,24 @@ static GHashTable *vips__object_nickname_table = NULL;
 
 G_DEFINE_ABSTRACT_TYPE( VipsObject, vips_object, G_TYPE_OBJECT );
 
+/* Don't call this directly, see vips_object_build().
+ */
+static int
+vips_object_postbuild( VipsObject *object )
+{
+	int result;
+
+#ifdef DEBUG
+	printf( "vips_object_postbuild: " );
+	vips_object_print_name( object );
+	printf( "\n" );
+#endif /*DEBUG*/
+
+	g_signal_emit( object, vips_object_signals[SIG_POSTBUILD], 0, &result );
+
+	return( result ); 
+}
+
 void
 vips_object_preclose( VipsObject *object )
 {
@@ -250,6 +271,11 @@ vips_object_build( VipsObject *object )
 	 */
 	object->constructed = TRUE;
 
+	/* Only postbuild on success.
+	 */
+	if( !result )
+		result = vips_object_postbuild( object );
+
 	return( result );
 }
 
@@ -1285,6 +1311,20 @@ vips_object_real_build( VipsObject *object )
 	return( result );
 }
 
+static int
+vips_object_real_postbuild( VipsObject *object )
+{
+#ifdef DEBUG
+	printf( "vips_object_real_postbuild: " ); 
+	vips_object_print_name( object );
+	printf( "\n" );
+#endif /*DEBUG*/
+
+	g_assert( object->constructed ); 
+
+	return( 0 ); 
+}
+
 static void
 vips_object_real_summary_class( VipsObjectClass *class, VipsBuf *buf )
 {
@@ -1384,6 +1424,7 @@ vips_object_class_init( VipsObjectClass *class )
 	gobject_class->get_property = vips_object_get_property;
 
 	class->build = vips_object_real_build;
+	class->postbuild = vips_object_real_postbuild;
 	class->summary_class = vips_object_real_summary_class;
 	class->summary = vips_object_real_summary;
 	class->dump = vips_object_real_dump;
@@ -1419,6 +1460,13 @@ vips_object_class_init( VipsObjectClass *class )
 		G_STRUCT_OFFSET( VipsObject, description ), 
 		"" );
 
+	vips_object_signals[SIG_POSTBUILD] = g_signal_new( "postbuild",
+		G_TYPE_FROM_CLASS( class ),
+		G_SIGNAL_RUN_LAST,
+		G_STRUCT_OFFSET( VipsObjectClass, postbuild ), 
+		NULL, NULL,
+		vips_INT__VOID,
+		G_TYPE_INT, 0 );
 	vips_object_signals[SIG_PRECLOSE] = g_signal_new( "preclose",
 		G_TYPE_FROM_CLASS( class ),
 		G_SIGNAL_RUN_LAST,
diff --git a/libvips/iofuncs/operation.c b/libvips/iofuncs/operation.c
index c75b812a..4f37ad2c 100644
--- a/libvips/iofuncs/operation.c
+++ b/libvips/iofuncs/operation.c
@@ -773,28 +773,30 @@ vips_call_find_pspec( VipsObject *object,
  */
 typedef struct _VipsCallOptionOutput {
 	VipsArgumentInstance *argument_instance;
-	const char *value;
+	char *value;
 } VipsCallOptionOutput;
 
-static void
+static int
 vips_call_option_output( VipsObject *object,
 	VipsCallOptionOutput *output )
 {
 	VipsArgumentInstance *argument_instance = output->argument_instance;
 	GParamSpec *pspec = ((VipsArgument *) argument_instance)->pspec;
 
+	int result;
+
 	/* Don't look at the output arg if _build() hasn't run sucessfully, it
 	 * probably won't have been set. 
 	 */
+	result = 0;
 	if( object->constructed )
-		if( vips_object_get_argument_to_string( object, 
-			g_param_spec_get_name( pspec ), output->value ) ) {
-			/* FIXME .. Hmm what can we do here? If an arg is image
-			 * output, for example, we will lose the error.
-			 */
-		}
+		result = vips_object_get_argument_to_string( object, 
+			g_param_spec_get_name( pspec ), output->value );
 
+	VIPS_FREE( output->value ); 
 	g_free( output );
+
+	return( result ); 
 }
 
 static gboolean
@@ -857,14 +859,11 @@ vips_call_options_set( const gchar *option_name, const gchar *value,
 
 		/* We can't do output now, we have to attach a callback to do
 		 * the processing after the operation has run.
-		 *
-		 * FIXME ... something like posteval or postbuild might be
-		 * better for this?
 		 */
 		output = g_new( VipsCallOptionOutput, 1 );
 		output->argument_instance = argument_instance;
-		output->value = value;
-		g_signal_connect( operation, "preclose",
+		output->value = g_strdup( value );
+		g_signal_connect( operation, "postbuild",
 			G_CALLBACK( vips_call_option_output ),
 			output );
 	}
diff --git a/libvips/iofuncs/system.c b/libvips/iofuncs/system.c
index 908de337..1f5cc241 100644
--- a/libvips/iofuncs/system.c
+++ b/libvips/iofuncs/system.c
@@ -62,21 +62,21 @@
 #include <errno.h>
 
 #include <vips/vips.h>
+#include <vips/internal.h>
 
 typedef struct _VipsSystem {
 	VipsOperation parent_instance;
 
-	VipsImage *in;
+	VipsArrayImage *in;
 	VipsImage *out;
 	char *cmd_format;
 	char *in_format;
 	char *out_format;
 	char *log;
 
-	/* Set to delete in_name on close.
+	/* Array of names we wrote the input images to.
 	 */
-	gboolean delete_on_close;
-	char *in_name;
+	char **in_name;
 
 	char *out_name;
 
@@ -91,11 +91,14 @@ vips_system_dispose( GObject *gobject )
 {
 	VipsSystem *system = (VipsSystem *) gobject;
 
-	if( system->delete_on_close &&
-		system->in_name ) 
-		g_unlink( system->in_name );
-	VIPS_FREE( system->in_name );
-	system->delete_on_close = FALSE;
+	if( system->in_name ) {
+		int i;
+
+		for( i = 0; i < system->in->n; i++ ) { 
+			g_unlink( system->in_name[i] );
+			VIPS_FREE( system->in_name[i] );
+		}
+	}
 
 	VIPS_FREE( system->out_name );
 
@@ -108,6 +111,10 @@ vips_system_build( VipsObject *object )
 	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
 	VipsSystem *system = (VipsSystem *) object;
 
+	int i;
+
+	char cmd[VIPS_PATH_MAX];
+
 	FILE *fp;
 	char line[VIPS_PATH_MAX];
 	char txt[VIPS_PATH_MAX];
@@ -117,19 +124,27 @@ vips_system_build( VipsObject *object )
 	if( VIPS_OBJECT_CLASS( vips_system_parent_class )->build( object ) )
 		return( -1 );
 
-	/* Write the input image to a file. We must always make a copy of the
-	 * file, even if this is a disc file already, in case the command
-	 * needs a different format.
+	/* Write the input images to files. We must always make copies of the
+	 * files, even if this image is a disc file already, in case the 
+	 * command needs a different format.
 	 */
 	if( system->in ) { 
 		char *in_format = system->in_format ? 
 			system->in_format : "%s.tif";
+		VipsImage **in = (VipsImage **) system->in->data; 
 
-		if( !(system->in_name = vips__temp_name( in_format )) )
-			return( -1 );
-		if( vips_image_write_to_file( system->in, system->in_name ) ) 
-			return( -1 );
-		system->delete_on_close = TRUE;
+		if( !(system->in_name = VIPS_ARRAY( object, 
+			system->in->n, char * )) )
+			return( -1 ); 
+		memset( system->in_name, 0, system->in->n * sizeof( char * ) ); 
+		for( i = 0; i < system->in->n; i++ ) { 
+			if( !(system->in_name[i] = 
+				vips__temp_name( in_format )) )
+				return( -1 );
+			if( vips_image_write_to_file( in[i], 
+				system->in_name[i] ) ) 
+				return( -1 );
+		}
 	}
 
 	/* Make the output filename.
@@ -138,16 +153,19 @@ vips_system_build( VipsObject *object )
 		!(system->out_name = vips__temp_name( system->out_format )) )
 		return( -1 ); 
 
-	if( system->in_name ) {
-		if( !(fp = vips_popenf( system->cmd_format, "r", 
-			system->in_name, system->out_name )) ) 
-			return( -1 );
-	}
-	else {
-		if( !(fp = vips_popenf( system->cmd_format, "r", 
-			system->out_name )) ) 
-			return( -1 );
-	}
+	vips_strncpy( cmd, system->cmd_format, VIPS_PATH_MAX );
+	if( system->in ) 
+		for( i = 0; i < system->in->n; i++ ) 
+			if( vips__substitute( class->nickname, 
+				cmd, VIPS_PATH_MAX, system->in_name[i] ) )
+				return( -1 ); 
+	if( system->out_name &&
+		vips__substitute( class->nickname, 
+			cmd, VIPS_PATH_MAX, system->out_name ) )
+		return( -1 ); 
+
+	if( !(fp = vips_popenf( "%s", "r", cmd )) )
+		return( -1 );
 
 	while( fgets( line, VIPS_PATH_MAX, fp ) ) 
 		if( !vips_buf_appends( &buf, line ) )
@@ -161,13 +179,12 @@ vips_system_build( VipsObject *object )
 		return( -1 ); 
 	}
 
-	if( system->out_format ) {
+	if( system->out_name ) {
 		VipsImage *out; 
 
 		if( !(out = vips_image_new_from_file( system->out_name )) )
 			return( -1 );
 		vips_image_set_delete_on_close( out, TRUE );
-
 		g_object_set( system, "out", out, NULL ); 
 	}
 
@@ -188,11 +205,12 @@ vips_system_class_init( VipsSystemClass *class )
 	vobject_class->description = _( "run an external command" );
 	vobject_class->build = vips_system_build;
 
-	VIPS_ARG_IMAGE( class, "in", 0, 
+	VIPS_ARG_BOXED( class, "in", 0, 
 		_( "Input" ), 
-		_( "Input image" ),
-		VIPS_ARGUMENT_OPTIONAL_INPUT, 
-		G_STRUCT_OFFSET( VipsSystem, in ) );
+		_( "Array of input images" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsSystem, in ),
+		VIPS_TYPE_ARRAY_IMAGE );
 
 	VIPS_ARG_IMAGE( class, "out", 1, 
 		_( "Output" ), 
@@ -242,21 +260,20 @@ vips_system_init( VipsSystem *system )
  *
  * Optional arguments:
  *
- * @in: input image 
+ * @in: array of input images
  * @out: output image
- * @in_format: write input file like this
+ * @in_format: write input files like this
  * @out_format: write output filename like this
  * @log: stdout of command is returned here
  *
- * vips_system() runs a command, optionally passing an image in and 
- * optionally getting an image
- * back. The command's stdout is returned in @log. 
+ * vips_system() runs a command, optionally passing a set of images in and 
+ * optionally getting an image back. The command's stdout is returned in @log. 
  *
- * First, if @in is set, it is written to a file. The filename is formed by 
- * substituting something like "vips-49857-1" for the first %%s in @in_format, 
- * then
- * prepending "/tmp". If the environment variable TMPDIR is defined, it
- * can be used to set a different temporary directory. 
+ * First, if @in is set, the array of images are written to files. The 
+ * filenames are formed by substituting something like "vips-49857-1" for 
+ * the first %%s in @in_format, then prepending "/tmp". If the environment 
+ * variable TMPDIR is defined, it can be used to set a different temporary 
+ * directory. 
  *
  * On Windows, if the environment variable TMPDIR is not defined, VIPS calls 
  * GetTempPath() to get the user's preferred temporary area. If that fails, it
@@ -268,16 +285,17 @@ vips_system_init( VipsSystem *system )
  *
  * If @out_format is set, an output filename is formed in the same way.
  *
- * The
- * command string to run is made by substituting the first %%s in @cmd_format
- * for the name of the input file, if @in is set, and the second %%s for the 
- * output filename, if set.
+ * The command string to run is made by substituting the first set of %%s 
+ * in @cmd_format for the names of the input files, if @in is set, and then 
+ * the next %%s for the output filename, if @out_format is set. 
+ * You can put a number between the %% and the s to change the order in which
+ * the substitution occurs.
  *
  * The command is executed with popen() and the output captured in @log. 
  *
  * After the command finishes, if @out_format is set, the output image is
  * opened and returned in @out. 
- * Closing the output image will automatically delete the output file.
+ * Closing @out image will automatically delete the output file.
  *
  * Finally the input images are deleted. 
  *
@@ -285,7 +303,7 @@ vips_system_init( VipsSystem *system )
  * image, using JPEG files to pass images into and out of the convert command.
  *
  * |[
- * VipsImage *in;
+ * VipsArrayImage *in;
  * VipsImage *out;
  * char *log;
  *
@@ -313,6 +331,3 @@ vips_system( const char *cmd_format, ... )
 
 	return( result );
 }
-
-
-
diff --git a/libvips/iofuncs/util.c b/libvips/iofuncs/util.c
index 2b608e54..2a816b90 100644
--- a/libvips/iofuncs/util.c
+++ b/libvips/iofuncs/util.c
@@ -1673,3 +1673,76 @@ vips_enum_from_nick( const char *domain, GType type, const char *nick )
 
 	return( -1 );
 }
+
+#define BIGBUF (10000)
+
+/* Scan @buf for the first "%ns" (eg. "%12s") and substitute the 
+ * lowest-numbered one for @sub. @buf is @len bytes
+ * in size.
+ *
+ * If there are no %ns, use the first %s.
+ */
+int
+vips__substitute( const char *domain, char *buf, size_t len, char *sub )
+{
+	size_t buflen = strlen( buf ); 
+	size_t sublen = strlen( sub ); 
+
+	int lowest_n;
+	char *sub_start;
+	char *p;
+	char *sub_end;
+	size_t before_len, marker_len, after_len, final_len;
+
+	g_assert( buflen < len ); 
+
+	lowest_n = -1;
+	sub_start = NULL;
+	for( p = buf; (p = strchr( p, '%' )); p++ )  
+		if( isdigit( p[1] ) ) {
+			char *q;
+
+			for( q = p + 1; isdigit( *q ); q++ )
+				;
+			if( q[0] == 's' ) {
+				int n;
+
+				n = atoi( p + 1 );
+				if( lowest_n == -1 ||
+					n < lowest_n ) {
+					sub_start = p;
+					sub_end = q + 1;
+				}
+			}
+		}
+
+	if( !sub_start ) 
+		for( p = buf; (p = strchr( p, '%' )); p++ )  
+			if( p[1] == 's' ) {
+				sub_start = p;
+				sub_end = p + 2;
+				break;
+			}
+
+	if( !sub_start ) {
+		vips_error( domain, 
+			"%s", _( "string contains no substitute marker" ) ); 
+		return( -1 ); 
+	}
+
+	before_len = sub_start - buf;
+	marker_len = sub_end - sub_start;
+	after_len = buflen - (before_len + marker_len);
+	final_len = before_len + sublen + after_len + 1;
+	if( final_len > len ) { 
+		vips_error( domain, 
+			"%s", _( "not enough space to substitute" ) ); 
+		return( -1 ); 
+	}
+
+	memmove( buf + before_len + sublen, buf + before_len + marker_len, 
+		after_len + 1 );  
+	memmove( buf + before_len, sub, sublen ); 
+
+	return( 0 ); 
+}
diff --git a/libvips/iofuncs/vipsmarshal.c b/libvips/iofuncs/vipsmarshal.c
new file mode 100644
index 00000000..655ffb32
--- /dev/null
+++ b/libvips/iofuncs/vipsmarshal.c
@@ -0,0 +1,89 @@
+#include "vipsmarshal.h"
+
+#include	<glib-object.h>
+
+
+#ifdef G_ENABLE_DEBUG
+#define g_marshal_value_peek_boolean(v)  g_value_get_boolean (v)
+#define g_marshal_value_peek_char(v)     g_value_get_schar (v)
+#define g_marshal_value_peek_uchar(v)    g_value_get_uchar (v)
+#define g_marshal_value_peek_int(v)      g_value_get_int (v)
+#define g_marshal_value_peek_uint(v)     g_value_get_uint (v)
+#define g_marshal_value_peek_long(v)     g_value_get_long (v)
+#define g_marshal_value_peek_ulong(v)    g_value_get_ulong (v)
+#define g_marshal_value_peek_int64(v)    g_value_get_int64 (v)
+#define g_marshal_value_peek_uint64(v)   g_value_get_uint64 (v)
+#define g_marshal_value_peek_enum(v)     g_value_get_enum (v)
+#define g_marshal_value_peek_flags(v)    g_value_get_flags (v)
+#define g_marshal_value_peek_float(v)    g_value_get_float (v)
+#define g_marshal_value_peek_double(v)   g_value_get_double (v)
+#define g_marshal_value_peek_string(v)   (char*) g_value_get_string (v)
+#define g_marshal_value_peek_param(v)    g_value_get_param (v)
+#define g_marshal_value_peek_boxed(v)    g_value_get_boxed (v)
+#define g_marshal_value_peek_pointer(v)  g_value_get_pointer (v)
+#define g_marshal_value_peek_object(v)   g_value_get_object (v)
+#define g_marshal_value_peek_variant(v)  g_value_get_variant (v)
+#else /* !G_ENABLE_DEBUG */
+/* WARNING: This code accesses GValues directly, which is UNSUPPORTED API.
+ *          Do not access GValues directly in your code. Instead, use the
+ *          g_value_get_*() functions
+ */
+#define g_marshal_value_peek_boolean(v)  (v)->data[0].v_int
+#define g_marshal_value_peek_char(v)     (v)->data[0].v_int
+#define g_marshal_value_peek_uchar(v)    (v)->data[0].v_uint
+#define g_marshal_value_peek_int(v)      (v)->data[0].v_int
+#define g_marshal_value_peek_uint(v)     (v)->data[0].v_uint
+#define g_marshal_value_peek_long(v)     (v)->data[0].v_long
+#define g_marshal_value_peek_ulong(v)    (v)->data[0].v_ulong
+#define g_marshal_value_peek_int64(v)    (v)->data[0].v_int64
+#define g_marshal_value_peek_uint64(v)   (v)->data[0].v_uint64
+#define g_marshal_value_peek_enum(v)     (v)->data[0].v_long
+#define g_marshal_value_peek_flags(v)    (v)->data[0].v_ulong
+#define g_marshal_value_peek_float(v)    (v)->data[0].v_float
+#define g_marshal_value_peek_double(v)   (v)->data[0].v_double
+#define g_marshal_value_peek_string(v)   (v)->data[0].v_pointer
+#define g_marshal_value_peek_param(v)    (v)->data[0].v_pointer
+#define g_marshal_value_peek_boxed(v)    (v)->data[0].v_pointer
+#define g_marshal_value_peek_pointer(v)  (v)->data[0].v_pointer
+#define g_marshal_value_peek_object(v)   (v)->data[0].v_pointer
+#define g_marshal_value_peek_variant(v)  (v)->data[0].v_pointer
+#endif /* !G_ENABLE_DEBUG */
+
+
+/* INT:VOID (vipsmarshal.list:25) */
+void
+vips_INT__VOID (GClosure     *closure,
+                GValue       *return_value G_GNUC_UNUSED,
+                guint         n_param_values,
+                const GValue *param_values,
+                gpointer      invocation_hint G_GNUC_UNUSED,
+                gpointer      marshal_data)
+{
+  typedef gint (*GMarshalFunc_INT__VOID) (gpointer     data1,
+                                          gpointer     data2);
+  register GMarshalFunc_INT__VOID callback;
+  register GCClosure *cc = (GCClosure*) closure;
+  register gpointer data1, data2;
+  gint v_return;
+
+  g_return_if_fail (return_value != NULL);
+  g_return_if_fail (n_param_values == 1);
+
+  if (G_CCLOSURE_SWAP_DATA (closure))
+    {
+      data1 = closure->data;
+      data2 = g_value_peek_pointer (param_values + 0);
+    }
+  else
+    {
+      data1 = g_value_peek_pointer (param_values + 0);
+      data2 = closure->data;
+    }
+  callback = (GMarshalFunc_INT__VOID) (marshal_data ? marshal_data : cc->callback);
+
+  v_return = callback (data1,
+                       data2);
+
+  g_value_set_int (return_value, v_return);
+}
+
diff --git a/libvips/iofuncs/vipsmarshal.h b/libvips/iofuncs/vipsmarshal.h
new file mode 100644
index 00000000..2f3e711f
--- /dev/null
+++ b/libvips/iofuncs/vipsmarshal.h
@@ -0,0 +1,20 @@
+
+#ifndef __vips_MARSHAL_H__
+#define __vips_MARSHAL_H__
+
+#include	<glib-object.h>
+
+G_BEGIN_DECLS
+
+/* INT:VOID (vipsmarshal.list:25) */
+extern void vips_INT__VOID (GClosure     *closure,
+                            GValue       *return_value,
+                            guint         n_param_values,
+                            const GValue *param_values,
+                            gpointer      invocation_hint,
+                            gpointer      marshal_data);
+
+G_END_DECLS
+
+#endif /* __vips_MARSHAL_H__ */
+
diff --git a/libvips/iofuncs/vipsmarshal.list b/libvips/iofuncs/vipsmarshal.list
new file mode 100644
index 00000000..0ce2c772
--- /dev/null
+++ b/libvips/iofuncs/vipsmarshal.list
@@ -0,0 +1,27 @@
+# see glib-genmarshal(1) for a detailed description of the file format,
+# possible parameter types are:
+#   VOID        indicates   no   return   type,  or  no  extra
+#               parameters. if VOID is used as  the  parameter
+#               list, no additional parameters may be present.
+#   BOOLEAN     for boolean types (gboolean)
+#   CHAR        for signed char types (gchar)
+#   UCHAR       for unsigned char types (guchar)
+#   INT         for signed integer types (gint)
+#   UINT        for unsigned integer types (guint)
+#   LONG        for signed long integer types (glong)
+#   ULONG       for unsigned long integer types (gulong)
+#   ENUM        for enumeration types (gint)
+#   FLAGS       for flag enumeration types (guint)
+#   FLOAT       for single-precision float types (gfloat)
+#   DOUBLE      for double-precision float types (gdouble)
+#   STRING      for string types (gchar*)
+#   BOXED       for boxed (anonymous but reference counted) types (GBoxed*)
+#   POINTER     for anonymous pointer types (gpointer)
+#   PARAM       for GParamSpec or derived types  (GParamSpec*)
+#   OBJECT      for GObject or derived types (GObject*)
+#   NONE        deprecated alias for VOID
+#   BOOL        deprecated alias for BOOLEAN
+
+INT: VOID
+
+