Document filter usage

[lttng-tools.git] / src / bin / lttng / commands / enable_events.c

diff --git a/src/bin/lttng/commands/enable_events.c b/src/bin/lttng/commands/enable_events.c
index 3f304a0902ad398bfddacc76ba97ca6595836685..de1796ad8ed0e7fa8f6fe06d363c7ad33787e8f0 100644 (file)
--- a/src/bin/lttng/commands/enable_events.c
+++ b/src/bin/lttng/commands/enable_events.c
@@ -168,6 +168,11 @@ static void usage(FILE *ofp)
        fprintf(ofp, "    --filter \'expression\'\n");
        fprintf(ofp, "                           Filter expression on event fields,\n");
        fprintf(ofp, "                           event recording depends on evaluation.\n");
+       fprintf(ofp, "                           Only specify on first activation of\n");
+       fprintf(ofp, "                           a given event within a session.\n");
+       fprintf(ofp, "                           Filter only allowed when enabling\n");
+       fprintf(ofp, "                           events within a session before tracing\n");
+       fprintf(ofp, "                           is started.\n");
        fprintf(ofp, "\n");
 }