+/**
+ * Add a trigger to the specified device (and the specified channel).
+ *
+ * If the specified channel of this device already has a trigger, it will
+ * be silently replaced.
+ *
+ * @param[in,out] sdi Pointer to the device instance; must not be NULL.
+ * @param[in] channelnum Number of channel, starting at 0.
+ * @param[in] trigger Trigger string, in the format used by sigrok-cli
+ *
+ * @return SR_OK on success or SR_ERR on failure. In case of invalid
+ * arguments, SR_ERR_ARG is returned and the trigger settings
+ * remain unchanged.
+ *
+ * @since 0.2.0
+ */
+SR_API int sr_dev_trigger_set(const struct sr_dev_inst *sdi, int channelnum,
+ const char *trigger)
+{
+ GSList *l;
+ struct sr_channel *ch;
+ char *old_trigger;
+ int ret;
+
+ if (!sdi)
+ return SR_ERR_ARG;
+
+ ret = SR_ERR_ARG;
+ for (l = sdi->channels; l; l = l->next) {
+ ch = l->data;
+ if (ch->index == channelnum) {
+ old_trigger = ch->trigger;
+ ret = SR_OK;
+ if (g_strcmp0(trigger, old_trigger) == 0)
+ break;
+ /* Set new trigger if it has changed. */
+ ch->trigger = g_strdup(trigger);
+
+ if (sdi->driver && sdi->driver->config_probe_set) {
+ ret = sdi->driver->config_probe_set(
+ sdi, ch, SR_PROBE_SET_TRIGGER);
+ /* Roll back change if it wasn't applicable. */
+ if (ret == SR_ERR_ARG) {
+ g_free(ch->trigger);
+ ch->trigger = old_trigger;
+ break;
+ }
+ }
+ g_free(old_trigger);
+ break;
+ }
+ }