lttng-ust-dl(3)
===============
:object-type: library


NAME
----
lttng-ust-dl - Dynamic linker tracing (LTTng-UST helper)


SYNOPSIS
--------
Launch your application by preloading `liblttng-ust-dl.so`:

[role="term"]
[verse]
*LD_PRELOAD=liblttng-ust-dl.so* my-app


DESCRIPTION
-----------
When the `liblttng-ust-dl.so` library is preloaded before a given
application starts, it causes all calls to man:dlopen(3) and
man:dlclose(3) in said application to be traced with LTTng-UST (see
man:lttng-ust(3)).

See man:lttng(1) to learn more about how to control LTTng tracing
sessions.

The following LTTng-UST events are available when using this library:

`lttng_ust_dl:dlopen`::
    Emitted when man:dlopen(3) is called.
+
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
|==============================================================

`lttng_ust_dl:dlclose`::
    Emitted when man:dlclose(3) is called.
+
Fields:
+
[options="header"]
|==============================================================
| Field name                 | Description
| `baddr`                    | Base address of loaded library
|==============================================================

`lttng_ust_dl:debug_link`::
    Emitted when debug link information is found when loading a library
    with man:dlopen(3). 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
| `filename`                 | Debug link file name
| `crc`                      | Debug link file's CRC
|==============================================================

`lttng_ust_dl:build_id`::
    Emitted when a build ID is found when loading a library
    with man:dlopen(3). 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
|==============================================================


include::common-footer.txt[]

include::common-copyrights.txt[]

include::common-authors.txt[]


SEE ALSO
--------
man:lttng-ust(3),
man:dlopen(3),
man:lttng(1)