6 This LTTng-UST helper causes all calls to `dlopen()` and `dlclose()`
7 in the target application to be traced with LTTng.
9 The helper's shared object, `liblttng-ust-dl.so`, registers the
10 following tracepoints when preloaded:
13 <table class="func-desc">
16 <th><abbr title="Tracepoint">TP</abbr> provider name</th>
17 <th><abbr title="Tracepoint">TP</abbr> name</th>
18 <th>Description/fields</th>
24 <code class="no-bg">lttng_ust_dl</code>
27 <code class="no-bg">dlopen</code>
30 <p><code>dlopen()</code> call</p>
34 <code class="arg">baddr</code> memory
36 (where the dynamic linker placed the shared
40 <code class="arg">sopath</code> file system
41 path to the loaded shared object
44 <code class="arg">size</code> file size
45 of the the loaded shared object
48 <code class="arg">mtime</code> last
49 modification time (seconds since Epoch time)
50 of the loaded shared object
57 <code class="no-bg">dlclose</code>
60 <p><code>dlclose()</code> call</p>
64 <code class="arg">baddr</code> memory
74 To use this LTTng-UST helper with any user application, independently of
75 how the latter is built, do:
78 LD_PRELOAD=liblttng-ust-dl.so my-app
81 Of course, like any other tracepoint, the ones above need to be enabled
82 in order for LTTng-UST to generate events. This is done using the
83 `lttng` command line tool
84 (see [Controlling tracing](#doc-controlling-tracing)).