+/*
+ * Add PID to session tracker.
+ * Return 0 on success else a negative LTTng error code.
+ */
+int lttng_track_pid(struct lttng_handle *handle, int pid)
+{
+ struct lttcomm_session_msg lsm;
+
+ /*
+ * NULL arguments are forbidden. No default values.
+ */
+ if (handle == NULL) {
+ return -LTTNG_ERR_INVALID;
+ }
+
+ memset(&lsm, 0, sizeof(lsm));
+
+ lsm.cmd_type = LTTNG_TRACK_PID;
+ lsm.u.pid_tracker.pid = pid;
+
+ lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+
+ lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+ sizeof(lsm.session.name));
+
+ return lttng_ctl_ask_sessiond(&lsm, NULL);
+}
+
+/*
+ * Remove PID from session tracker.
+ * Return 0 on success else a negative LTTng error code.
+ */
+int lttng_untrack_pid(struct lttng_handle *handle, int pid)
+{
+ struct lttcomm_session_msg lsm;
+
+ /*
+ * NULL arguments are forbidden. No default values.
+ */
+ if (handle == NULL) {
+ return -LTTNG_ERR_INVALID;
+ }
+
+ memset(&lsm, 0, sizeof(lsm));
+
+ lsm.cmd_type = LTTNG_UNTRACK_PID;
+ lsm.u.pid_tracker.pid = pid;
+
+ lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+
+ lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+ sizeof(lsm.session.name));
+
+ return lttng_ctl_ask_sessiond(&lsm, NULL);
+}
+