contents/understanding-lttng/plumbing/liblttng-ctl-lttng.md

   1 ---
   2 id: liblttng-ctl-lttng
   3 ---
   4
   5 The LTTng control library, `liblttng-ctl`, can be used to communicate
   6 with the session daemon using a C API that hides the underlying
   7 protocol's details. `liblttng-ctl` is part of LTTng-tools.
   8
   9 `liblttng-ctl` may be used by including its "master" header:
  10
  11 ~~~ c
  12 #include <lttng/lttng.h>
  13 ~~~
  14
  15 Some objects are referred by name (C string), such as tracing sessions,
  16 but most of them require creating a handle first using
  17 `lttng_create_handle()`. The best available developer documentation for
  18 `liblttng-ctl` is, for the moment, its installed header files as such.
  19 Every function/structure is thoroughly documented.
  20
  21 The `lttng` program is the _de facto_ standard user interface to
  22 control LTTng tracing sessions. `lttng` uses `liblttng-ctl` to
  23 communicate with session daemons behind the scenes.
  24 <a href="/man/1/lttng" class="ext">Its manpage</a> is exhaustive, as
  25 well as its command line help (<code>lttng <em>cmd</em> --help</code>,
  26 where <code><em>cmd</em></code> is the command name).
  27
  28 The [Controlling tracing](#doc-controlling-tracing) section is a feature
  29 tour of the `lttng` tool.