8 lttng-ust-dl - Dynamic linker tracing (LTTng-UST helper)
13 Launch your application by preloading `liblttng-ust-dl.so`:
17 *LD_PRELOAD=liblttng-ust-dl.so* my-app
22 When the `liblttng-ust-dl.so` library is preloaded before a given
23 application starts, it causes all calls to man:dlopen(3) and
24 man:dlclose(3) in said application to be traced with LTTng-UST (see
27 See man:lttng(1) to learn more about how to control LTTng tracing
30 IMPORTANT: This LTTng-UST helper can also emit _shared library
31 load/unload_ events (see _Shared library load/unload tracking_ in
32 man:lttng-ust(3)). You should :not: use the event records generated by
33 this LTTng-UST helper (prefixed with `lttng_ust_dl:`) to track the
34 loading and unloading of shared libraries, especially in situations
35 where a dynamically loaded library loads its own dependencies. Instead,
36 do preload `liblttng-ust-dl.so`, but use the shared library load/unload
37 event records, which are more reliable, for your tracking analysis.
39 The following LTTng-UST events are available when using this library.
42 `lttng_ust_dl:dlopen`::
43 Emitted when man:dlopen(3) is called.
49 |Field name |Description
52 |Base address of loaded library.
55 |Size of loaded library in memory.
58 |Path to loaded library file.
61 `lttng_ust_dl:dlclose`::
62 Emitted when man:dlclose(3) is called.
68 |Field name |Description
71 |Base address of loaded library.
74 `lttng_ust_dl:debug_link`::
75 Emitted when debug link information is found when loading a library
76 with man:dlopen(3). See
77 https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html[Debugging Information in Separate Files]
78 for more information about debug links.
84 |Field name |Description
87 |Base address of loaded library.
90 |Debug link file name.
93 |Debug link file's CRC.
96 `lttng_ust_dl:build_id`::
97 Emitted when a build ID is found when loading a library
98 with man:dlopen(3). See
99 https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html[Debugging Information in Separate Files]
100 for more information about build IDs.
106 |Field name |Description
109 |Base address of loaded library.
116 include::common-footer.txt[]
118 include::common-copyrights.txt[]
120 include::common-authors.txt[]