diff --git a/cplusplus/gen-operators.py b/cplusplus/gen-operators.py
index 9b8f4687..03a63f63 100755
--- a/cplusplus/gen-operators.py
+++ b/cplusplus/gen-operators.py
@@ -25,7 +25,7 @@
 
 import argparse
 
-from pyvips import Image, Operation, GValue, Error, \
+from pyvips import Operation, GValue, Error, \
     ffi, gobject_lib, type_map, type_from_name, nickname_find, type_name
 
 # turn a GType into a C++ type
@@ -33,7 +33,7 @@ gtype_to_cpp = {
     GValue.gbool_type: 'bool',
     GValue.gint_type: 'int',
     GValue.gdouble_type: 'double',
-    GValue.gstr_type: 'char *',
+    GValue.gstr_type: 'const char *',
     GValue.refstr_type: 'char *',
     GValue.gflags_type: 'int',
     GValue.image_type: 'VImage',
diff --git a/cplusplus/include/vips/vips-operators.h b/cplusplus/include/vips/vips-operators.h
index 059f8dc9..f59ce970 100644
--- a/cplusplus/include/vips/vips-operators.h
+++ b/cplusplus/include/vips/vips-operators.h
@@ -1,5 +1,5 @@
 // headers for vips operations
-// Sun  3 Feb 13:10:05 GMT 2019
+// Wed Apr 24 15:50:21 CEST 2019
 // this file is generated automatically, do not edit!
 
 /**
@@ -164,7 +164,7 @@ VImage affine( std::vector<double> matrix, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage analyzeload( char *filename, VOption *options = 0 );
+static VImage analyzeload( const char *filename, VOption *options = 0 );
 
 /**
  * Join an array of images.
@@ -451,14 +451,14 @@ VImage crop( int left, int top, int width, int height, VOption *options = 0 ) co
  * @param options Optional options.
  * @return Output image.
  */
-static VImage csvload( char *filename, VOption *options = 0 );
+static VImage csvload( const char *filename, VOption *options = 0 );
 
 /**
  * Save image to csv file.
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void csvsave( char *filename, VOption *options = 0 ) const;
+void csvsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Calculate de00.
@@ -574,7 +574,7 @@ void draw_smudge( int left, int top, int width, int height, VOption *options = 0
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void dzsave( char *filename, VOption *options = 0 ) const;
+void dzsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Save image to dz buffer.
@@ -660,14 +660,14 @@ int find_trim( int *top, int *width, int *height, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage fitsload( char *filename, VOption *options = 0 );
+static VImage fitsload( const char *filename, VOption *options = 0 );
 
 /**
  * Save image to fits file.
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void fitssave( char *filename, VOption *options = 0 ) const;
+void fitssave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Flatten alpha out of an image.
@@ -764,7 +764,7 @@ std::vector<double> getpoint( int x, int y, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage gifload( char *filename, VOption *options = 0 );
+static VImage gifload( const char *filename, VOption *options = 0 );
 
 /**
  * Load gif with giflib.
@@ -810,6 +810,36 @@ static VImage grey( int width, int height, VOption *options = 0 );
  */
 VImage grid( int tile_height, int across, int down, VOption *options = 0 ) const;
 
+/**
+ * Load a heif image.
+ * @param filename Filename to load from.
+ * @param options Optional options.
+ * @return Output image.
+ */
+static VImage heifload( const char *filename, VOption *options = 0 );
+
+/**
+ * Load a heif image.
+ * @param buffer Buffer to load from.
+ * @param options Optional options.
+ * @return Output image.
+ */
+static VImage heifload_buffer( VipsBlob *buffer, VOption *options = 0 );
+
+/**
+ * Save image in heif format.
+ * @param filename Filename to load from.
+ * @param options Optional options.
+ */
+void heifsave( const char *filename, VOption *options = 0 ) const;
+
+/**
+ * Save image in heif format.
+ * @param options Optional options.
+ * @return Buffer to save to.
+ */
+VipsBlob *heifsave_buffer( VOption *options = 0 ) const;
+
 /**
  * Form cumulative histogram.
  * @param options Optional options.
@@ -925,7 +955,7 @@ VImage icc_import( VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-VImage icc_transform( char *output_profile, VOption *options = 0 ) const;
+VImage icc_transform( const char *output_profile, VOption *options = 0 ) const;
 
 /**
  * Make a 1d image where pixel values are indexes.
@@ -989,7 +1019,7 @@ VImage join( VImage in2, VipsDirection direction, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage jpegload( char *filename, VOption *options = 0 );
+static VImage jpegload( const char *filename, VOption *options = 0 );
 
 /**
  * Load jpeg from buffer.
@@ -1004,7 +1034,7 @@ static VImage jpegload_buffer( VipsBlob *buffer, VOption *options = 0 );
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void jpegsave( char *filename, VOption *options = 0 ) const;
+void jpegsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Save image to jpeg buffer.
@@ -1057,7 +1087,7 @@ static VImage logmat( double sigma, double min_ampl, VOption *options = 0 );
  * @param options Optional options.
  * @return Output image.
  */
-static VImage magickload( char *filename, VOption *options = 0 );
+static VImage magickload( const char *filename, VOption *options = 0 );
 
 /**
  * Load buffer with imagemagick.
@@ -1072,7 +1102,7 @@ static VImage magickload_buffer( VipsBlob *buffer, VOption *options = 0 );
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void magicksave( char *filename, VOption *options = 0 ) const;
+void magicksave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Save image to magick buffer.
@@ -1263,7 +1293,7 @@ VImage math2_const( VipsOperationMath2 math2, std::vector<double> c, VOption *op
  * @param options Optional options.
  * @return Output image.
  */
-static VImage matload( char *filename, VOption *options = 0 );
+static VImage matload( const char *filename, VOption *options = 0 );
 
 /**
  * Load matrix from file.
@@ -1271,7 +1301,7 @@ static VImage matload( char *filename, VOption *options = 0 );
  * @param options Optional options.
  * @return Output image.
  */
-static VImage matrixload( char *filename, VOption *options = 0 );
+static VImage matrixload( const char *filename, VOption *options = 0 );
 
 /**
  * Print matrix.
@@ -1284,7 +1314,7 @@ void matrixprint( VOption *options = 0 ) const;
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void matrixsave( char *filename, VOption *options = 0 ) const;
+void matrixsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Find image maximum.
@@ -1380,14 +1410,14 @@ VImage multiply( VImage right, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage niftiload( char *filename, VOption *options = 0 );
+static VImage niftiload( const char *filename, VOption *options = 0 );
 
 /**
  * Save image to nifti file.
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void niftisave( char *filename, VOption *options = 0 ) const;
+void niftisave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Load an openexr image.
@@ -1395,7 +1425,7 @@ void niftisave( char *filename, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage openexrload( char *filename, VOption *options = 0 );
+static VImage openexrload( const char *filename, VOption *options = 0 );
 
 /**
  * Load file with openslide.
@@ -1403,7 +1433,7 @@ static VImage openexrload( char *filename, VOption *options = 0 );
  * @param options Optional options.
  * @return Output image.
  */
-static VImage openslideload( char *filename, VOption *options = 0 );
+static VImage openslideload( const char *filename, VOption *options = 0 );
 
 /**
  * Load pdf with libpoppler.
@@ -1411,7 +1441,7 @@ static VImage openslideload( char *filename, VOption *options = 0 );
  * @param options Optional options.
  * @return Output image.
  */
-static VImage pdfload( char *filename, VOption *options = 0 );
+static VImage pdfload( const char *filename, VOption *options = 0 );
 
 /**
  * Load pdf with libpoppler.
@@ -1452,7 +1482,7 @@ VImage phasecor( VImage in2, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage pngload( char *filename, VOption *options = 0 );
+static VImage pngload( const char *filename, VOption *options = 0 );
 
 /**
  * Load png from buffer.
@@ -1467,7 +1497,7 @@ static VImage pngload_buffer( VipsBlob *buffer, VOption *options = 0 );
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void pngsave( char *filename, VOption *options = 0 ) const;
+void pngsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Save image to png buffer.
@@ -1482,14 +1512,14 @@ VipsBlob *pngsave_buffer( VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage ppmload( char *filename, VOption *options = 0 );
+static VImage ppmload( const char *filename, VOption *options = 0 );
 
 /**
  * Save image to ppm file.
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void ppmsave( char *filename, VOption *options = 0 ) const;
+void ppmsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Premultiply image alpha.
@@ -1512,7 +1542,7 @@ VImage profile( VImage *rows, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Loaded profile.
  */
-static VipsBlob *profile_load( char *name, VOption *options = 0 );
+static VipsBlob *profile_load( const char *name, VOption *options = 0 );
 
 /**
  * Find image projections.
@@ -1543,14 +1573,14 @@ VImage rad2float( VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage radload( char *filename, VOption *options = 0 );
+static VImage radload( const char *filename, VOption *options = 0 );
 
 /**
  * Save image to radiance file.
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void radsave( char *filename, VOption *options = 0 ) const;
+void radsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Save image to radiance buffer.
@@ -1578,14 +1608,14 @@ VImage rank( int width, int height, int index, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage rawload( char *filename, int width, int height, int bands, VOption *options = 0 );
+static VImage rawload( const char *filename, int width, int height, int bands, VOption *options = 0 );
 
 /**
  * Save image to raw file.
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void rawsave( char *filename, VOption *options = 0 ) const;
+void rawsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Write raw image to file descriptor.
@@ -1891,7 +1921,7 @@ static VImage sum( std::vector<VImage> in, VOption *options = 0 );
  * @param options Optional options.
  * @return Output image.
  */
-static VImage svgload( char *filename, VOption *options = 0 );
+static VImage svgload( const char *filename, VOption *options = 0 );
 
 /**
  * Load svg with rsvg.
@@ -1906,7 +1936,7 @@ static VImage svgload_buffer( VipsBlob *buffer, VOption *options = 0 );
  * @param cmd_format Command to run.
  * @param options Optional options.
  */
-static void system( char *cmd_format, VOption *options = 0 );
+static void system( const char *cmd_format, VOption *options = 0 );
 
 /**
  * Make a text image.
@@ -1914,7 +1944,7 @@ static void system( char *cmd_format, VOption *options = 0 );
  * @param options Optional options.
  * @return Output image.
  */
-static VImage text( char *text, VOption *options = 0 );
+static VImage text( const char *text, VOption *options = 0 );
 
 /**
  * Generate thumbnail from file.
@@ -1923,7 +1953,7 @@ static VImage text( char *text, VOption *options = 0 );
  * @param options Optional options.
  * @return Output image.
  */
-static VImage thumbnail( char *filename, int width, VOption *options = 0 );
+static VImage thumbnail( const char *filename, int width, VOption *options = 0 );
 
 /**
  * Generate thumbnail from buffer.
@@ -1948,7 +1978,7 @@ VImage thumbnail_image( int width, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage tiffload( char *filename, VOption *options = 0 );
+static VImage tiffload( const char *filename, VOption *options = 0 );
 
 /**
  * Load tiff from buffer.
@@ -1963,7 +1993,7 @@ static VImage tiffload_buffer( VipsBlob *buffer, VOption *options = 0 );
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void tiffsave( char *filename, VOption *options = 0 ) const;
+void tiffsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Save image to tiff buffer.
@@ -2006,14 +2036,14 @@ VImage unpremultiply( VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage vipsload( char *filename, VOption *options = 0 );
+static VImage vipsload( const char *filename, VOption *options = 0 );
 
 /**
  * Save image to vips file.
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void vipssave( char *filename, VOption *options = 0 ) const;
+void vipssave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Load webp from file.
@@ -2021,7 +2051,7 @@ void vipssave( char *filename, VOption *options = 0 ) const;
  * @param options Optional options.
  * @return Output image.
  */
-static VImage webpload( char *filename, VOption *options = 0 );
+static VImage webpload( const char *filename, VOption *options = 0 );
 
 /**
  * Load webp from buffer.
@@ -2036,7 +2066,7 @@ static VImage webpload_buffer( VipsBlob *buffer, VOption *options = 0 );
  * @param filename Filename to save to.
  * @param options Optional options.
  */
-void webpsave( char *filename, VOption *options = 0 ) const;
+void webpsave( const char *filename, VOption *options = 0 ) const;
 
 /**
  * Save image to webp buffer.
diff --git a/cplusplus/vips-operators.cpp b/cplusplus/vips-operators.cpp
index 2465e4d6..beae5057 100644
--- a/cplusplus/vips-operators.cpp
+++ b/cplusplus/vips-operators.cpp
@@ -1,5 +1,5 @@
 // bodies for vips operations
-// Sun  3 Feb 13:09:56 GMT 2019
+// Wed Apr 24 15:50:21 CEST 2019
 // this file is generated automatically, do not edit!
 
 VImage VImage::CMC2LCh( VOption *options ) const
@@ -268,7 +268,7 @@ VImage VImage::affine( std::vector<double> matrix, VOption *options ) const
     return( out );
 }
 
-VImage VImage::analyzeload( char *filename, VOption *options )
+VImage VImage::analyzeload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -729,7 +729,7 @@ VImage VImage::crop( int left, int top, int width, int height, VOption *options
     return( out );
 }
 
-VImage VImage::csvload( char *filename, VOption *options )
+VImage VImage::csvload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -741,7 +741,7 @@ VImage VImage::csvload( char *filename, VOption *options )
     return( out );
 }
 
-void VImage::csvsave( char *filename, VOption *options ) const
+void VImage::csvsave( const char *filename, VOption *options ) const
 {
     call( "csvsave",
         (options ? options : VImage::option())->
@@ -890,7 +890,7 @@ void VImage::draw_smudge( int left, int top, int width, int height, VOption *opt
             set( "height", height ) );
 }
 
-void VImage::dzsave( char *filename, VOption *options ) const
+void VImage::dzsave( const char *filename, VOption *options ) const
 {
     call( "dzsave",
         (options ? options : VImage::option())->
@@ -1020,7 +1020,7 @@ int VImage::find_trim( int *top, int *width, int *height, VOption *options ) con
     return( left );
 }
 
-VImage VImage::fitsload( char *filename, VOption *options )
+VImage VImage::fitsload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -1032,7 +1032,7 @@ VImage VImage::fitsload( char *filename, VOption *options )
     return( out );
 }
 
-void VImage::fitssave( char *filename, VOption *options ) const
+void VImage::fitssave( const char *filename, VOption *options ) const
 {
     call( "fitssave",
         (options ? options : VImage::option())->
@@ -1181,7 +1181,7 @@ std::vector<double> VImage::getpoint( int x, int y, VOption *options ) const
     return( out_array );
 }
 
-VImage VImage::gifload( char *filename, VOption *options )
+VImage VImage::gifload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -1260,6 +1260,50 @@ VImage VImage::grid( int tile_height, int across, int down, VOption *options ) c
     return( out );
 }
 
+VImage VImage::heifload( const char *filename, VOption *options )
+{
+    VImage out;
+
+    call( "heifload",
+        (options ? options : VImage::option())->
+            set( "out", &out )->
+            set( "filename", filename ) );
+
+    return( out );
+}
+
+VImage VImage::heifload_buffer( VipsBlob *buffer, VOption *options )
+{
+    VImage out;
+
+    call( "heifload_buffer",
+        (options ? options : VImage::option())->
+            set( "out", &out )->
+            set( "buffer", buffer ) );
+
+    return( out );
+}
+
+void VImage::heifsave( const char *filename, VOption *options ) const
+{
+    call( "heifsave",
+        (options ? options : VImage::option())->
+            set( "in", *this )->
+            set( "filename", filename ) );
+}
+
+VipsBlob *VImage::heifsave_buffer( VOption *options ) const
+{
+    VipsBlob *buffer;
+
+    call( "heifsave_buffer",
+        (options ? options : VImage::option())->
+            set( "in", *this )->
+            set( "buffer", &buffer ) );
+
+    return( buffer );
+}
+
 VImage VImage::hist_cum( VOption *options ) const
 {
     VImage out;
@@ -1444,7 +1488,7 @@ VImage VImage::icc_import( VOption *options ) const
     return( out );
 }
 
-VImage VImage::icc_transform( char *output_profile, VOption *options ) const
+VImage VImage::icc_transform( const char *output_profile, VOption *options ) const
 {
     VImage out;
 
@@ -1547,7 +1591,7 @@ VImage VImage::join( VImage in2, VipsDirection direction, VOption *options ) con
     return( out );
 }
 
-VImage VImage::jpegload( char *filename, VOption *options )
+VImage VImage::jpegload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -1571,7 +1615,7 @@ VImage VImage::jpegload_buffer( VipsBlob *buffer, VOption *options )
     return( out );
 }
 
-void VImage::jpegsave( char *filename, VOption *options ) const
+void VImage::jpegsave( const char *filename, VOption *options ) const
 {
     call( "jpegsave",
         (options ? options : VImage::option())->
@@ -1649,7 +1693,7 @@ VImage VImage::logmat( double sigma, double min_ampl, VOption *options )
     return( out );
 }
 
-VImage VImage::magickload( char *filename, VOption *options )
+VImage VImage::magickload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -1673,7 +1717,7 @@ VImage VImage::magickload_buffer( VipsBlob *buffer, VOption *options )
     return( out );
 }
 
-void VImage::magicksave( char *filename, VOption *options ) const
+void VImage::magicksave( const char *filename, VOption *options ) const
 {
     call( "magicksave",
         (options ? options : VImage::option())->
@@ -1939,7 +1983,7 @@ VImage VImage::math2_const( VipsOperationMath2 math2, std::vector<double> c, VOp
     return( out );
 }
 
-VImage VImage::matload( char *filename, VOption *options )
+VImage VImage::matload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -1951,7 +1995,7 @@ VImage VImage::matload( char *filename, VOption *options )
     return( out );
 }
 
-VImage VImage::matrixload( char *filename, VOption *options )
+VImage VImage::matrixload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -1970,7 +2014,7 @@ void VImage::matrixprint( VOption *options ) const
             set( "in", *this ) );
 }
 
-void VImage::matrixsave( char *filename, VOption *options ) const
+void VImage::matrixsave( const char *filename, VOption *options ) const
 {
     call( "matrixsave",
         (options ? options : VImage::option())->
@@ -2111,7 +2155,7 @@ VImage VImage::multiply( VImage right, VOption *options ) const
     return( out );
 }
 
-VImage VImage::niftiload( char *filename, VOption *options )
+VImage VImage::niftiload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -2123,7 +2167,7 @@ VImage VImage::niftiload( char *filename, VOption *options )
     return( out );
 }
 
-void VImage::niftisave( char *filename, VOption *options ) const
+void VImage::niftisave( const char *filename, VOption *options ) const
 {
     call( "niftisave",
         (options ? options : VImage::option())->
@@ -2131,7 +2175,7 @@ void VImage::niftisave( char *filename, VOption *options ) const
             set( "filename", filename ) );
 }
 
-VImage VImage::openexrload( char *filename, VOption *options )
+VImage VImage::openexrload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -2143,7 +2187,7 @@ VImage VImage::openexrload( char *filename, VOption *options )
     return( out );
 }
 
-VImage VImage::openslideload( char *filename, VOption *options )
+VImage VImage::openslideload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -2155,7 +2199,7 @@ VImage VImage::openslideload( char *filename, VOption *options )
     return( out );
 }
 
-VImage VImage::pdfload( char *filename, VOption *options )
+VImage VImage::pdfload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -2218,7 +2262,7 @@ VImage VImage::phasecor( VImage in2, VOption *options ) const
     return( out );
 }
 
-VImage VImage::pngload( char *filename, VOption *options )
+VImage VImage::pngload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -2242,7 +2286,7 @@ VImage VImage::pngload_buffer( VipsBlob *buffer, VOption *options )
     return( out );
 }
 
-void VImage::pngsave( char *filename, VOption *options ) const
+void VImage::pngsave( const char *filename, VOption *options ) const
 {
     call( "pngsave",
         (options ? options : VImage::option())->
@@ -2262,7 +2306,7 @@ VipsBlob *VImage::pngsave_buffer( VOption *options ) const
     return( buffer );
 }
 
-VImage VImage::ppmload( char *filename, VOption *options )
+VImage VImage::ppmload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -2274,7 +2318,7 @@ VImage VImage::ppmload( char *filename, VOption *options )
     return( out );
 }
 
-void VImage::ppmsave( char *filename, VOption *options ) const
+void VImage::ppmsave( const char *filename, VOption *options ) const
 {
     call( "ppmsave",
         (options ? options : VImage::option())->
@@ -2307,7 +2351,7 @@ VImage VImage::profile( VImage *rows, VOption *options ) const
     return( columns );
 }
 
-VipsBlob *VImage::profile_load( char *name, VOption *options )
+VipsBlob *VImage::profile_load( const char *name, VOption *options )
 {
     VipsBlob *profile;
 
@@ -2357,7 +2401,7 @@ VImage VImage::rad2float( VOption *options ) const
     return( out );
 }
 
-VImage VImage::radload( char *filename, VOption *options )
+VImage VImage::radload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -2369,7 +2413,7 @@ VImage VImage::radload( char *filename, VOption *options )
     return( out );
 }
 
-void VImage::radsave( char *filename, VOption *options ) const
+void VImage::radsave( const char *filename, VOption *options ) const
 {
     call( "radsave",
         (options ? options : VImage::option())->
@@ -2404,7 +2448,7 @@ VImage VImage::rank( int width, int height, int index, VOption *options ) const
     return( out );
 }
 
-VImage VImage::rawload( char *filename, int width, int height, int bands, VOption *options )
+VImage VImage::rawload( const char *filename, int width, int height, int bands, VOption *options )
 {
     VImage out;
 
@@ -2419,7 +2463,7 @@ VImage VImage::rawload( char *filename, int width, int height, int bands, VOptio
     return( out );
 }
 
-void VImage::rawsave( char *filename, VOption *options ) const
+void VImage::rawsave( const char *filename, VOption *options ) const
 {
     call( "rawsave",
         (options ? options : VImage::option())->
@@ -2909,7 +2953,7 @@ VImage VImage::sum( std::vector<VImage> in, VOption *options )
     return( out );
 }
 
-VImage VImage::svgload( char *filename, VOption *options )
+VImage VImage::svgload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -2933,14 +2977,14 @@ VImage VImage::svgload_buffer( VipsBlob *buffer, VOption *options )
     return( out );
 }
 
-void VImage::system( char *cmd_format, VOption *options )
+void VImage::system( const char *cmd_format, VOption *options )
 {
     call( "system",
         (options ? options : VImage::option())->
             set( "cmd_format", cmd_format ) );
 }
 
-VImage VImage::text( char *text, VOption *options )
+VImage VImage::text( const char *text, VOption *options )
 {
     VImage out;
 
@@ -2952,7 +2996,7 @@ VImage VImage::text( char *text, VOption *options )
     return( out );
 }
 
-VImage VImage::thumbnail( char *filename, int width, VOption *options )
+VImage VImage::thumbnail( const char *filename, int width, VOption *options )
 {
     VImage out;
 
@@ -2991,7 +3035,7 @@ VImage VImage::thumbnail_image( int width, VOption *options ) const
     return( out );
 }
 
-VImage VImage::tiffload( char *filename, VOption *options )
+VImage VImage::tiffload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -3015,7 +3059,7 @@ VImage VImage::tiffload_buffer( VipsBlob *buffer, VOption *options )
     return( out );
 }
 
-void VImage::tiffsave( char *filename, VOption *options ) const
+void VImage::tiffsave( const char *filename, VOption *options ) const
 {
     call( "tiffsave",
         (options ? options : VImage::option())->
@@ -3082,7 +3126,7 @@ VImage VImage::unpremultiply( VOption *options ) const
     return( out );
 }
 
-VImage VImage::vipsload( char *filename, VOption *options )
+VImage VImage::vipsload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -3094,7 +3138,7 @@ VImage VImage::vipsload( char *filename, VOption *options )
     return( out );
 }
 
-void VImage::vipssave( char *filename, VOption *options ) const
+void VImage::vipssave( const char *filename, VOption *options ) const
 {
     call( "vipssave",
         (options ? options : VImage::option())->
@@ -3102,7 +3146,7 @@ void VImage::vipssave( char *filename, VOption *options ) const
             set( "filename", filename ) );
 }
 
-VImage VImage::webpload( char *filename, VOption *options )
+VImage VImage::webpload( const char *filename, VOption *options )
 {
     VImage out;
 
@@ -3126,7 +3170,7 @@ VImage VImage::webpload_buffer( VipsBlob *buffer, VOption *options )
     return( out );
 }
 
-void VImage::webpsave( char *filename, VOption *options ) const
+void VImage::webpsave( const char *filename, VOption *options ) const
 {
     call( "webpsave",
         (options ? options : VImage::option())->
diff --git a/doc/gen-function-list.py b/doc/gen-function-list.py
index 5856bd3e..d1394b32 100755
--- a/doc/gen-function-list.py
+++ b/doc/gen-function-list.py
@@ -1,48 +1,68 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 
-# walk vips and generate a list of all operators and their descriptions 
+# walk vips and generate a list of all operators and their descriptions
 # for docs
 
+# this needs pyvips
+#
+#   pip install --user pyvips
+
 # sample output:
 
 # <row>
 #   <entry>gamma</entry>
-#   <entry>gamma an image</entry>
+#   <entry>Gamma an image</entry>
 #   <entry>vips_gamma()</entry>
 # </row>
 
-import gi
-gi.require_version('Vips', '8.0')
-from gi.repository import Vips, GObject
+from pyvips import Operation, Error, \
+    ffi, type_map, type_from_name, nickname_find
 
-vips_type_operation = GObject.GType.from_name("VipsOperation")
+# for VipsOperationFlags
+_OPERATION_DEPRECATED = 8
 
-def gen_function(cls):
-    op = Vips.Operation.new(cls.name)
-    gtype = Vips.type_find("VipsOperation", cls.name)
-    nickname = Vips.nickname_find(gtype)
 
-    print '<row>'
-    print '  <entry>%s</entry>' % nickname
-    print '  <entry>%s</entry>' % op.get_description()
-    print '  <entry>vips_%s()</entry>' % nickname
-    print '</row>'
+def gen_function(operation_name):
+    op = Operation.new_from_name(operation_name)
 
-# we have a few synonyms ... don't generate twice
-generated = {}
+    print('<row>')
+    print('  <entry>{}</entry>'.format(operation_name))
+    print('  <entry>{}</entry>'.format(op.get_description().capitalize()))
+    print('  <entry>vips_{}()</entry>'.format(operation_name))
+    print('</row>')
 
-def gen_function_list(cls):
-    if not cls.is_abstract():
-        gtype = Vips.type_find("VipsOperation", cls.name)
-        nickname = Vips.nickname_find(gtype)
-        if not nickname in generated:
-            gen_function(cls)
-            generated[nickname] = True
 
-    if len(cls.children) > 0:
-        for child in cls.children:
-            gen_function_list(child)
+def gen_function_list():
+    all_nicknames = []
+
+    def add_nickname(gtype, a, b):
+        nickname = nickname_find(gtype)
+        try:
+            # can fail for abstract types
+            op = Operation.new_from_name(nickname)
+
+            # we are only interested in non-deprecated operations
+            if (op.get_flags() & _OPERATION_DEPRECATED) == 0:
+                all_nicknames.append(nickname)
+        except Error:
+            pass
+
+        type_map(gtype, add_nickname)
+
+        return ffi.NULL
+
+    type_map(type_from_name('VipsOperation'), add_nickname)
+
+    # add 'missing' synonyms by hand
+    all_nicknames.append('crop')
+
+    # make list unique and sort
+    all_nicknames = list(set(all_nicknames))
+    all_nicknames.sort()
+
+    for nickname in all_nicknames:
+        gen_function(nickname)
+
 
 if __name__ == '__main__':
-    gen_function_list(vips_type_operation)
-
+    gen_function_list()
diff --git a/doc/using-cpp.xml b/doc/using-cpp.xml
index be1cbeae..fcda9677 100644
--- a/doc/using-cpp.xml
+++ b/doc/using-cpp.xml
@@ -181,7 +181,7 @@ int vips_add( VipsImage *left, VipsImage *right, VipsImage **out, ... );
       appears in C++ as:
 
 <programlisting language="cpp">
-VImage VImage::add( VImage right, VOption *options = 0 );
+VImage VImage::add( VImage right, VOption *options ) const
 </programlisting>
     </para>
 
@@ -312,7 +312,7 @@ int vips_sin( VipsImage *in, VipsImage **out, ... );
       and a C++ member function VImage::sin():
 
 <programlisting language="cpp">
-VImage VImage::sin( VOption *options = 0 );
+VImage VImage::sin( VOption *options = 0 ) const
 </programlisting>
 
     </para>
@@ -354,8 +354,8 @@ void VImage::set( const char *field, const char *value );
 
 <programlisting language="cpp">
 VImage im = VImage::new_from_file( "x.jpg" )
-int orientation = atoi( im.get_string( "exif-ifd0-Orientation" ) );
-im.set( "exif-ifd0-Orientation", "2" );
+int orientation = im.get_int( VIPS_META_ORIENTATION );
+im.set( VIPS_META_ORIENTATION, 2 );
 im.write_to_file( "y.jpg" );
 </programlisting>
     </para>
@@ -372,11 +372,10 @@ im.write_to_file( "y.jpg" );
     </para>
 
     <para>
-      The member function for each operation, for example VImage::add(), is 
-      generated by a small Python program called <code>gen-operators.py</code>,
-      and its companion, <code>gen-operators-h.py</code> to generate the 
-      headers. If you write a new VIPS operator, you'll need to rerun these 
-      programs to make the new member function. 
+      The member definition and declaration for each operation, for example
+      VImage::add(), is generated by a small Python program called
+      <code>gen-operators.py</code>. If you write a new VIPS operator, you'll
+      need to rerun this program to make it visible in the C++ interface.
     </para>
 
     <para>
@@ -384,17 +383,17 @@ im.write_to_file( "y.jpg" );
       The one for VImage::add() looks like this:
 
 <programlisting language="cpp">
-VImage VImage::add(VImage right, VOption *options)
+VImage VImage::add( VImage right, VOption *options ) const
 {
-  VImage out;
+    VImage out;
 
-  call("add" ,
-    (options ? options : VImage::option()) ->
-      set("out", &amp;out) ->
-      set("left", *this) ->
-      set("right", right));
+    call("add",
+        (options ? options : VImage::option())->
+            set("out", &amp;out)->
+            set("left", *this)->
+            set("right", right));
 
-  return out;
+    return out;
 }
 </programlisting>