+|===
+|Field name |Description
+
+|`baddr`
+|Base address of loaded library.
+
+|`crc`
+|Debug link file's CRC.
+
+|`filename`
+|Debug link file name.
+|===
+
+
+[[ust-lib]]
+Shared library load/unload tracking
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The <<state-dump,LTTng-UST state dump>> and the LTTng-UST helper library
+to instrument the dynamic linker (see man:liblttng-ust-dl(3)) can emit
+**shared library load/unload tracking** events.
+
+The following shared library load/unload tracking events exist and must
+be enabled to track the loading and unloading of shared libraries:
+
+`lttng_ust_lib:load`::
+ Emitted when a shared library (shared object) is loaded.
++
+Fields:
++
+[options="header"]
+|===
+|Field name |Description
+
+|`baddr`
+|Base address of loaded library.
+
+|`memsz`
+|Size of loaded library in memory.
+
+|`path`
+|Path to loaded library file.
+
+|`has_build_id`
+|Whether or not the library has a build ID. If this field is 1, you
+can expect that an `lttng_ust_lib:build_id` event record follows
+this one (not necessarily immediately after).
+
+|`has_debug_link`
+|Whether or not the library has debug link information. If this field
+is 1, you can expect that an `lttng_ust_lib:debug_link` event
+record follows this one (not necessarily immediately after).
+|===
+
+`lttng_ust_lib:unload`::
+ Emitted when a shared library (shared object) is unloaded.
++
+Fields:
++
+[options="header"]
+|===
+|Field name |Description
+
+|`baddr`
+|Base address of unloaded library.
+|===
+
+`lttng_ust_lib:build_id`::
+ Emitted when a build ID is found in a loaded shared library (shared
+ object). See
+ https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html[Debugging Information in Separate Files]
+ for more information about build IDs.
++
+Fields:
++
+[options="header"]
+|===
+|Field name |Description
+
+|`baddr`
+|Base address of loaded library.
+
+|`build_id`
+|Build ID.
+|===
+
+`lttng_ust_lib:debug_link`::
+ Emitted when debug link information is found in a loaded
+ shared library (shared object). See
+ https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html[Debugging Information in Separate Files]
+ for more information about debug links.
++
+Fields:
++
+[options="header"]
+|===
+|Field name |Description
+
+|`baddr`
+|Base address of loaded library.
+
+|`crc`
+|Debug link file's CRC.
+
+|`filename`
+|Debug link file name.
+|===
+
+
+Detect if LTTng-UST is loaded
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+To detect if `liblttng-ust` is loaded from an application:
+
+. Define the `lttng_ust_loaded` weak symbol globally:
++
+------------------------------------------------------------------------
+int lttng_ust_loaded __attribute__((weak));
+------------------------------------------------------------------------
++
+This weak symbol is set by the constructor of `liblttng-ust`.
+
+. Test `lttng_ust_loaded` where needed:
++
+------------------------------------------------------------------------
+/* ... */
+
+if (lttng_ust_loaded) {
+ /* LTTng-UST is loaded */
+} else {
+ /* LTTng-UST is NOT loaded */
+}
+
+/* ... */
+------------------------------------------------------------------------