#ifndef LTTNG_NOTIFICATION_CHANNEL_H
#define LTTNG_NOTIFICATION_CHANNEL_H
+#include <stdbool.h>
+
#ifdef __cplusplus
extern "C" {
#endif
enum lttng_notification_channel_status {
LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED = 1,
+ LTTNG_NOTIFICATION_CHANNEL_STATUS_INTERRUPTED = 2,
LTTNG_NOTIFICATION_CHANNEL_STATUS_OK = 0,
LTTNG_NOTIFICATION_CHANNEL_STATUS_ERROR = -1,
LTTNG_NOTIFICATION_CHANNEL_STATUS_CLOSED = -2,
* Notifications can be dropped if a client consumes the notifications sent
* through the notification channel too slowly.
*
- * Returns LTTNG_NOTIFICATION_CHANNEL_STATUS_OK and a notification on success,
- * LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID if an invalid parameter was
- * provided, or LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED if
- * notifications were dropped.
+ * Returns
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_OK and a notification on success,
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID if an invalid parameter was
+ * provided,
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED if notifications
+ * were dropped,
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_INTERRUPTED if a signal was received
+ * that caused the reception to fail.
*/
extern enum lttng_notification_channel_status
lttng_notification_channel_get_next_notification(
struct lttng_notification_channel *channel,
struct lttng_notification **notification);
+/*
+ * Check whether a notification is pending on a notification channel.
+ *
+ * This call allows the user to check whether a notification is pending on
+ * the notification channel.
+ *
+ * If pending is set to true and the return value is
+ * LTTNG_NOTIFICATION_CHANNEL_STATUS_OK,
+ * lttng_notification_channel_get_next_notification() can be called and
+ * is guaranteed to not block.
+ *
+ * Returns
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_OK on success,
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID if an invalid parameter was
+ * provided.
+ */
+extern enum lttng_notification_channel_status
+lttng_notification_channel_has_pending_notification(
+ struct lttng_notification_channel *channel,
+ bool *notification_pending);
+
/*
* Subscribe to notifications of a condition through a notification channel.
*
* An error will be reported if the client tries to subscribe to the same
* condition multiple times without unsubscribing.
*
- * Returns LTTNG_NOTIFICATION_CHANNEL_STATUS_OK on success,
- * LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID if an invalid parameter was
- * provided, or LTTNG_NOTIFICATION_CHANNEL_STATUS_ALREADY_SUBSCRIBED if the
- * client was already subscribed to the condition through this channel.
+ * Returns
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_OK on success,
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID if an invalid parameter was
+ * provided, or LTTNG_NOTIFICATION_CHANNEL_STATUS_ALREADY_SUBSCRIBED if the
+ * client was already subscribed to the condition through this channel.
*/
extern enum lttng_notification_channel_status
lttng_notification_channel_subscribe(
* An error will be reported if the client tries to unsubscribe to from a
* conditions' notifications to which it was not previously subscribed.
*
- * Returns LTTNG_NOTIFICATION_CHANNEL_STATUS_OK on success,
- * LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID if an invalid parameter was
- * provided, or LTTNG_NOTIFICATION_CHANNEL_STATUS_UNKNOWN_CONDITION if the
- * client was not already subscribed to the condition through this channel.
+ * Returns
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_OK on success,
+ * - LTTNG_NOTIFICATION_CHANNEL_STATUS_INVALID if an invalid parameter was
+ * provided, or LTTNG_NOTIFICATION_CHANNEL_STATUS_UNKNOWN_CONDITION if the
+ * client was not already subscribed to the condition through this channel.
*/
extern enum lttng_notification_channel_status
lttng_notification_channel_unsubscribe(