diff --git a/operational b/operational
index 945cb84af43e23caafa5490e357a7eff44047ab3..f8a7f76ee6053c5c6ee84ea04e0562fab435d8fd 100644
--- a/operational
+++ b/operational
@@ -1,8 +1,15 @@
 * COMMENT -*- mode: org -*-
 #+Date: 2019-04-05
-Time-stamp: <2019-10-23>
+Time-stamp: <2020-02-02>
 #+STARTUP: content
 * notes                                                               :entry:
+** 2020-02-02 documents
+- Wrap best practices and tips
+  https://mesonbuild.com/Wrap-best-practices-and-tips.html
+- meson build Reference manual
+  https://mesonbuild.com/Reference-manual.html
+- 
+
 ** 2019-08-31 ibus-pinyin userdb inference notice.
 zero-pinyin-service reuse ibus-pinyin's userdb at
 ~/.cache/ibus/pinyin/user-1.0.db
@@ -98,6 +105,39 @@ see ~/c/gtk-im-module/, it uses myastyle-pre-commit-check in git pre-commit
 - make the method work. use gobject property maybe.
 - set default flags to my flags. reflect this in UI/config file.
 * done                                                                :entry:
+** 2020-02-02 how to use zero-pinyin-service dbus service using C client?
+see example in ~/c/gtk-im-module/zero-pinyin.c
+
+#include <zero-pinyin-service-generated.h>
+
+- WONTFIX make zero-pinyin-generated a library.
+
+- I choose to include the dbus xml in the project, and generated new header/C
+  files there. Still need to define a few const for object name etc though.
+
+- problems
+  - only an so (libzero-pinyin-generated.so) is generated.
+    how to install header files?
+    search: meson library() how to install headers?
+
+    install_headers()
+
+  - search: meson install_headers from generated source file
+
+    Generated headers cannot be installed directly · Issue #705 · mesonbuild/meson
+    https://github.com/mesonbuild/meson/issues/705
+    foo.vapi files generated by Vala library() should be installed · Issue #891 · mesonbuild/meson
+    https://github.com/mesonbuild/meson/issues/891
+
+    use install_data to install header files myself.
+
+    #+BEGIN_SRC sh
+      install_data(meson.current_build_dir() + '/foo.vapi', 
+                   install_dir: 'share/vala/vapi')
+      install_data(meson.current_build_dir() + '/foo@sha/Foo-1.0.gir', 
+                   install_dir: 'share/gir-1.0')
+    #+END_SRC
+
 ** 2019-10-22 support fuzzy pinyin.
 - 0 no fuzzy
 - 1 (0b1)