lttng-ust(3): document liblttng-ust-fd

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/doc/man/lttng-ust.3.txt b/doc/man/lttng-ust.3.txt
index 8ecda775b3477f363a8c234109e4d9a95802f67d..ed525f6e9866a31e7dfc2b8987be4c0d880f7f6a 100644 (file)
--- a/doc/man/lttng-ust.3.txt
+++ b/doc/man/lttng-ust.3.txt
@@ -738,6 +738,12 @@ without a following man:exec(3) family system call. The library
 application with the `LD_PRELOAD` environment variable (see
 man:ld.so(8)).
 
+To use `liblttng-ust` with a daemon application which closes file
+descriptors that were not opened by it, preload the `liblttng-ust-fd.so`
+library before you start the application. Typical use cases include
+daemons closing all file descriptors after man:fork(2), and buggy
+applications doing ``double-closes''.
+
 
 Context information
 ~~~~~~~~~~~~~~~~~~~