diff --git a/ChangeLog b/ChangeLog
index 9f19380f..ab5930cb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,8 @@
 - add VIPS_META_PAGE_HEIGHT metadata
 - IM6/IM7 magickload supports page/n/page-height, all_frames deprecated
 - gifload supports n/page-height
+- added #defines for VIPS_SONAME, VIPS_LIBRARY_CURRENT, VIPS_LIBRARY_REVISION,
+  VIPS_LIBRARY_AGE
 
 8/12/16 started 8.4.5
 - allow libgsf-1.14.26 to help centos, thanks tdiprima
diff --git a/libvips/Makefile.am b/libvips/Makefile.am
index 015ac722..fa678ff6 100644
--- a/libvips/Makefile.am
+++ b/libvips/Makefile.am
@@ -64,6 +64,10 @@ EXTRA_DIST = \
 
 CLEANFILES = 
 
+all-local:
+	echo '/* This file is autogenerated, do not edit. */' > include/vips/soname.h; \
+	source libvips.la; echo "#define VIPS_SONAME \"$$dlname\"" >> include/vips/soname.h; 
+
 -include $(INTROSPECTION_MAKEFILE)
 INTROSPECTION_GIRS =
 INTROSPECTION_SCANNER_ARGS = --add-include-path=$(srcdir)
diff --git a/libvips/include/vips/Makefile.am b/libvips/include/vips/Makefile.am
index 33630384..69f51b28 100644
--- a/libvips/include/vips/Makefile.am
+++ b/libvips/include/vips/Makefile.am
@@ -37,6 +37,7 @@ pkginclude_HEADERS = \
 	region.h \
 	resample.h \
 	semaphore.h \
+	soname.h \
 	threadpool.h \
 	thread.h \
 	transform.h \
@@ -70,6 +71,7 @@ vips_scan_headers = \
 	${top_srcdir}/libvips/include/vips/morphology.h \
 	${top_srcdir}/libvips/include/vips/draw.h \
 	${top_srcdir}/libvips/include/vips/basic.h \
+	${top_srcdir}/libvips/include/vips/version.h \
 	${top_srcdir}/libvips/include/vips/object.h
 
 enumtypes.h: $(vips_scan_headers) Makefile
diff --git a/libvips/include/vips/private.h b/libvips/include/vips/private.h
index d9648190..6e3bd497 100644
--- a/libvips/include/vips/private.h
+++ b/libvips/include/vips/private.h
@@ -56,11 +56,6 @@ extern "C" {
  */
 #define VIPS_SIZEOF_HEADER (64)
 
-/* Startup ABI check.
- */
-int vips__init( const char *argv0 );
-size_t vips__get_sizeof_vipsobject( void );
-
 /* What we track for each mmap window. Have a list of these on an openin
  * VipsImage.
  */
@@ -183,6 +178,11 @@ void vips__demand_hint_array( struct _VipsImage *image,
 int vips__image_copy_fields_array( struct _VipsImage *out, 
 	struct _VipsImage *in[] );
 
+/* Deprecated.
+ */
+int vips__init( const char *argv0 );
+size_t vips__get_sizeof_vipsobject( void );
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/
diff --git a/libvips/include/vips/soname.h b/libvips/include/vips/soname.h
new file mode 100644
index 00000000..7fd6c91d
--- /dev/null
+++ b/libvips/include/vips/soname.h
@@ -0,0 +1,2 @@
+/* This file is autogenerated, do not edit. */
+#define VIPS_SONAME "libvips.so.42"
diff --git a/libvips/include/vips/version.h.in b/libvips/include/vips/version.h.in
index 85a2a5ae..465f3f8e 100644
--- a/libvips/include/vips/version.h.in
+++ b/libvips/include/vips/version.h.in
@@ -10,6 +10,21 @@
 #define VIPS_MINOR_VERSION	(@VIPS_MINOR_VERSION@)
 #define VIPS_MICRO_VERSION	(@VIPS_MICRO_VERSION@)
 
+/* The ABI version, as used for library versioning.
+ */
+#define VIPS_LIBRARY_CURRENT	(@LIBRARY_CURRENT@)
+#define VIPS_LIBRARY_REVISION	(@LIBRARY_REVISION@)
+#define VIPS_LIBRARY_AGE	(@LIBRARY_AGE@)
+
+/** 
+ * VIPS_SONAME:
+ *
+ * The name of the shared object containing the vips library, for example
+ * "libvips.so.42", or "libvips-42.dll".
+ */
+
+#include "soname.h"
+
 /* Not really anything to do with versions, but this is a handy place to put
  * it.
  */
diff --git a/libvips/include/vips/vips.h b/libvips/include/vips/vips.h
index 174eeb3e..cb21d52d 100644
--- a/libvips/include/vips/vips.h
+++ b/libvips/include/vips/vips.h
@@ -164,14 +164,15 @@ extern "C" {
  * not have _().
  */
 #define VIPS_INIT( ARGV0 ) \
-	(sizeof( VipsObject ) != vips__get_sizeof_vipsobject() ? ( \
+	(vips_version( 3 ) - vips_version( 5 ) != \
+	 	VIPS_LIBRARY_CURRENT - VIPS_LIBRARY_AGE ? ( \
 		vips_info( "vips_init", "ABI mismatch" ), \
 		vips_info( "vips_init", \
-			"library has sizeof(VipsObject) == %zd", \
-			vips__get_sizeof_vipsobject() ), \
+			"library has ABI version %d", \
+			vips_version( 3 ) - vips_version( 5 ) ), \
 		vips_info( "vips_init", \
-			"application has sizeof(VipsObject) == %zd", \
-			sizeof( VipsObject ) ), \
+			"application needs ABI version %d", \
+			VIPS_LIBRARY_CURRENT - VIPS_LIBRARY_AGE ), \
 		vips_error( "vips_init", "ABI mismatch" ), \
 		-1 ) : \
 		vips_init( ARGV0 ))
diff --git a/libvips/iofuncs/Makefile.am b/libvips/iofuncs/Makefile.am
index eff85d1b..0a7807dc 100644
--- a/libvips/iofuncs/Makefile.am
+++ b/libvips/iofuncs/Makefile.am
@@ -68,6 +68,7 @@ vips_scan_headers = \
 	${top_srcdir}/libvips/include/vips/morphology.h \
 	${top_srcdir}/libvips/include/vips/draw.h \
 	${top_srcdir}/libvips/include/vips/basic.h \
+	${top_srcdir}/libvips/include/vips/version.h \
 	${top_srcdir}/libvips/include/vips/object.h
 
 enumtypes.c: $(vips_scan_headers) Makefile
diff --git a/libvips/iofuncs/init.c b/libvips/iofuncs/init.c
index 5650be42..3aa7a4c4 100644
--- a/libvips/iofuncs/init.c
+++ b/libvips/iofuncs/init.c
@@ -432,20 +432,6 @@ vips_init( const char *argv0 )
 	return( 0 );
 }
 
-/* Return the sizeof() various important data structures. These are checked
- * against the headers used to build our caller by vips_init().
- *
- * We allow direct access to members of VipsImage and VipsRegion (mostly for
- * reasons of history), so any change to a superclass of either of these
- * objects will break our ABI.
- */
-
-size_t
-vips__get_sizeof_vipsobject( void )
-{
-	return( sizeof( VipsObject ) ); 
-}
-
 /* Call this before vips stuff that uses stuff we need to have inited.
  */
 void
@@ -1029,6 +1015,9 @@ vips_version_string( void )
  * Get the major, minor or micro library version, with @flag values 0, 1 and
  * 2.
  *
+ * Get the ABI current, revision and age (as used by libtool) with @flag 
+ * values 3, 4, 5. 
+ *
  * Returns: library version number
  */
 int
@@ -1037,15 +1026,24 @@ vips_version( int flag )
 	switch( flag ) {
 	case 0:
 		return( VIPS_MAJOR_VERSION );
-	
+
 	case 1:
 		return( VIPS_MINOR_VERSION );
-	
+
 	case 2:
 		return( VIPS_MICRO_VERSION );
 
+	case 3:
+		return( VIPS_LIBRARY_CURRENT );
+
+	case 4:
+		return( VIPS_LIBRARY_REVISION );
+
+	case 5:
+		return( VIPS_LIBRARY_AGE );
+
 	default:
-		vips_error( "vips_version", "%s", _( "flag not 0, 1, 2" ) );
+		vips_error( "vips_version", "%s", _( "flag not in [0, 5]" ) );
 		return( -1 );
 	}
 }
@@ -1064,3 +1062,12 @@ vips_leak_set( gboolean leak )
 {
 	vips__leak = leak; 
 }
+
+/* Deprecated.
+ */
+size_t
+vips__get_sizeof_vipsobject( void )
+{
+	return( sizeof( VipsObject ) ); 
+}
+