diff --git a/vnc.h b/vnc.h
index 2fbe614..cd6495f 100644
--- a/vnc.h
+++ b/vnc.h
@@ -398,13 +398,13 @@
 void vnc_convert_pixel(VncState *vs, uint8_t *buf, uint32_t v);
 
 /* Encodings */
-void vnc_raw_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
+int vnc_raw_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
 
-void vnc_hextile_send_framebuffer_update(VncState *vs, int x,
+int vnc_hextile_send_framebuffer_update(VncState *vs, int x,
                                          int y, int w, int h);
 void vnc_hextile_set_pixel_conversion(VncState *vs, int generic);
 
-void vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
+int vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
 void vnc_zlib_clear(VncState *vs);
 
 #endif /* __QEMU_VNC_H */