+ struct lttng_session *session, int is_open);
+
+/*
+ * Machine interface: open a domains element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_domains_open(struct mi_writer *writer);
+
+/*
+ * Machine interface of struct domain.
+ *
+ * writer An instance of a machine interface writer.
+ * domain An instance of a domain.
+ *
+ * is_open Defines whether or not the session element shall be closed.
+ * This should be used carefully and the client
+ * must close the domain element.
+ * Use case: nested addition information on a domain
+ * ex: channel event.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_domain(struct mi_writer *writer,
+ struct lttng_domain *domain, int is_open);
+
+/*
+ * Machine interface: open a channels element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_channels_open(struct mi_writer *writer);
+
+/*
+ * Machine interface of struct channel.
+ *
+ * writer An instance of a machine interface writer.
+ * channel An instance of a channel.
+ *
+ * is_open Defines whether or not the session element shall be closed.
+ * This should be used carefully and the client
+ * must close the channel element.
+ * Use case: nested addition information on a channel.
+ * ex: channel event.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_channel(struct mi_writer *writer,
+ struct lttng_channel *channel, int is_open);
+
+/*
+ * Machine interface of struct channel_attr.
+ *
+ * writer An instance of a machine interface writer.
+ * attr An instance of a channel_attr struct.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_channel_attr(struct mi_writer *writer,
+ struct lttng_channel_attr *attr);
+
+/*
+* Machine interface for event common attributes.
+*
+* writer An instance of a mi writer.
+* event single trace event.
+*
+* The common attribute are:
+* - mi event element
+* - event name
+* - event type
+* - enabled tag
+* - event filter
+*
+* Returns zero if the element's value could be written.
+* Negative values indicate an error.
+*/
+int mi_lttng_event_common_attributes(struct mi_writer *writer,
+ struct lttng_event *event);
+
+/*
+ * Machine interface for kernel tracepoint event with a loglevel.
+ *
+ * writer An instance of a mi writer.
+ * event single trace event.
+ * domain Event's domain
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_event_tracepoint_loglevel(struct mi_writer *writer,
+ struct lttng_event *event, enum lttng_domain_type domain);
+
+/*
+ * Machine interface for kernel tracepoint event with no loglevel.
+ *
+ * writer An instance of a mi writer.
+ * event single trace event.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_event_tracepoint_no_loglevel(struct mi_writer *writer,
+ struct lttng_event *event);
+
+/*
+ * Machine interface for kernel function and probe event.
+ *
+ * writer An instance of a mi writer.
+ * event single trace event.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_event_function_probe(struct mi_writer *writer,
+ struct lttng_event *event);
+
+/*
+ * Machine interface for kernel function entry event.
+ *
+ * writer An instance of a mi writer.
+ * event single trace event.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_event_function_entry(struct mi_writer *writer,
+ struct lttng_event *event);
+
+/*
+ * Machine interface: open an events element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_events_open(struct mi_writer *writer);
+
+/*
+ * Machine interface for printing an event.
+ * The trace event type currently supported are:
+ * TRACEPOINT,
+ * PROBE,
+ * FUNCTION,
+ * FUNCTION_ENTRY,
+ * SYSCALL
+ *
+ * writer An instance of a mi writer.
+ * event single trace event.
+ * is_open Defines whether or not the session element shall be closed.
+ * This should be used carefully and the client
+ * must close the event element.
+ * Use case: nested additional information
+ * domain Event's domain
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_event(struct mi_writer *writer, struct lttng_event *event,
+ int is_open, enum lttng_domain_type domain);
+
+/*
+ * Machine interface for struct lttng_event_field.
+ *
+ * writer An instance of a mi writer.
+ * field An event_field instance.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_event_field(struct mi_writer *writer,
+ struct lttng_event_field *field);
+
+/*
+ * Machine interface: open a event_fields element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element have be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_event_fields_open(struct mi_writer *writer);
+
+/*
+ * Machine interface: open a trackers element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_trackers_open(struct mi_writer *writer);
+
+/*
+ * Machine interface: open a pid_tracker element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ *
+ * Note: A targets element is also opened for each tracker definition
+ */
+int mi_lttng_pid_tracker_open(struct mi_writer *writer);
+
+/*
+ * Machine interface: open a PIDs element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_pids_open(struct mi_writer *writer);
+
+/*
+ * Machine interface: open a processes element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_processes_open(struct mi_writer *writer);
+
+/*
+ * Machine interface of a Process.
+ *
+ * writer An instance of a machine interface writer.
+ * pid A PID.
+ *
+ * is_open Defines whether or not the session element shall be closed.
+ * This should be used carefully and the client
+ * must close the pid element.
+ * Use case: nested addition information on a domain
+ * ex: channel event.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_process(struct mi_writer *writer, pid_t pid , const char *name,
+ int is_open);
+
+/*
+ * TODO: move pid of lttng list -u to process semantic on mi api bump
+ * Machine interface of a Process.
+ *
+ * writer An instance of a machine interface writer.
+ * pid A PID.
+ *
+ * is_open Defines whether or not the session element shall be closed.
+ * This should be used carefully and the client
+ * must close the pid element.
+ * Use case: nested addition information on a domain
+ * ex: channel event.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_pid(struct mi_writer *writer, pid_t pid , const char *name,
+ int is_open);
+/*
+ * Machine interface: open a targets element.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_targets_open(struct mi_writer *writer);
+
+/*
+ * Machine interface for track/untrack a pid_target
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_pid_target(struct mi_writer *writer, pid_t pid, int is_open);
+
+/*
+ * Machine interface of a context.
+ *
+ * writer An instance of a machine interface writer
+ *
+ * context An instance of a lttng_event_context
+ *
+ * is_open Define if we close the context element
+ * This should be used carefully and the client
+ * need to close the context element.
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_context(struct mi_writer *writer,
+ struct lttng_event_context *context, int is_open);
+
+/*
+ * Machine interface of a perf_counter_context.
+ *
+ * writer An instance of a machine interface writer
+ *
+ * contest An instance of a lttng_event_perf_counter_ctx
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_perf_counter_context(struct mi_writer *writer,
+ struct lttng_event_perf_counter_ctx *perf_context);
+
+/*
+ * Machine interface of the snapshot list_output.
+ * It specifies the session for which we are listing snapshots,
+ * and it opens a snapshots element to list a sequence
+ * of snapshots.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * session_name: Snapshot output for session "session_name".
+ *
+ * Note: The client has to close the session and the snapshots elements after
+ * having listed every lttng_snapshot_output.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_output_session_name(struct mi_writer *writer,
+ const char *session_name);
+
+/*
+ * Machine interface of the snapshot output.
+ * The machine interface serializes the following attributes:
+ * - id: ID of the snapshot output.
+ * - name: Name of the output.
+ * - data_url : Destination of the output.
+ * - ctrl_url: Destination of the output.
+ * - max_size: total size of all stream combined.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * output: A list of snapshot_output.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_list_output(struct mi_writer *writer,
+ struct lttng_snapshot_output *output);
+
+/*
+ * Machine interface of the output of the command snapshot del output
+ * when deleting a snapshot either by id or by name.
+ * If the snapshot was found and successfully deleted using its id,
+ * it return the id of the snapshot and the current session name on which it
+ * was attached.
+ *
+ * Otherwise, it do the same process with the name of the snapshot, if the
+ * snapshot output id is undefined.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * id: ID of the snapshot output.
+ *
+ * name: Name of the snapshot.
+ *
+ * current_session_name: Session to which the snapshot belongs.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_del_output(struct mi_writer *writer, int id,
+ const char *name, const char *current_session_name);
+
+/*
+ * Machine interface of the output of the command snapshot add output
+ * when adding a snapshot from a user URL.
+ *
+ * If the snapshot was successfully added, the machine interface lists
+ * these information:
+ * - id: ID of the newly add snapshot output.
+ * - current_session_name: Name of the session to which the output was added.
+ * - ctrl_url: Destination of the output.
+ * - max_size: total size of all stream combined.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * current_session_name: Session to which the snapshot belongs.
+ *
+ * n_ptr:
+ *
+ * output: iterator over a lttng_snapshot_output_list which contain
+ * the snapshot output informations.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_add_output(struct mi_writer *writer,
+ const char *current_session_name, const char *n_ptr,
+ struct lttng_snapshot_output *output);
+
+/*
+ * Machine interface of the output of the command snapshot
+ * record from a URL (if given).
+ *
+ * If the snapshot is successfully recorded from a url, the machine interface
+ * output the following information:
+ * - url: Destination of the output stored in the snapshot.
+ *
+ * Otherwise, the machine interface output the data and ctrl url received
+ * from the command-line.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * current_session_name: Snapshot record for session "current_session_name".
+ *
+ * ctrl_url, data_url: Destination of the output receive from the command-line.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_record(struct mi_writer *writer,
+ const char *current_session_name, const char *url,
+ const char *cmdline_ctrl_url, const char *cmdline_data_url);
+
+/*
+ * Machine interface representation of a session rotation schedule.
+ *
+ * The machine interface serializes the provided schedule as one of the choices
+ * from 'rotation_schedule_type'.
+ *
+ * writer: An instance of a machine interface writer.
+ *
+ * schedule: An lttng rotation schedule descriptor object.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_rotation_schedule(struct mi_writer *writer,
+ const struct lttng_rotation_schedule *schedule);
+
+/*
+ * Machine interface of a session rotation schedule result.
+ * This is an element that is part of the output of the enable-rotation and
+ * disable-rotation commands.
+ *
+ * The machine interface provides the following information:
+ * - schedule: the session rotation schedule descriptor.
+ * - success: whether the sub-command succeeded.
+ *
+ * writer: An instance of a machine interface writer.
+ *
+ * schedule: An lttng rotation schedule descriptor object.
+ *
+ * success: Whether the sub-command suceeded.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_rotation_schedule_result(struct mi_writer *writer,
+ const struct lttng_rotation_schedule *schedule,
+ bool success);
+
+/*
+ * Machine interface of a session rotation result.
+ * This is an element that is part of the output of the rotate command.
+ *
+ * The machine interface provides the following information:
+ * - session_name: the session to be rotated.
+ * - state: the session rotation state.
+ * - location: the location of the completed chunk archive.
+ *
+ * writer: An instance of a machine interface writer.
+ *
+ * session_name: The session to which the rotate command applies.
+ *
+ * location: A location descriptor object.
+ *
+ * success: Whether the sub-command suceeded.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_rotate(struct mi_writer *writer,
+ const char *session_name,
+ enum lttng_rotation_state rotation_state,
+ const struct lttng_trace_archive_location *location);