+/**
+ * @brief Wait for a vblank with the target sequence number
+ * @details
+ * This function will return error when HW vblank resource is not available. However,
+ * #tdm_client_vblank_wait will return TDM_ERROR_NONE as success if
+ * #tdm_client_vblank_set_enable_fake sets true. Once #tdm_client_vblank_wait_seq
+ * returns TDM_ERROR_NONE, the user client vblank handler(#tdm_client_vblank_handler)
+ * SHOULD be called on reaching the target sequence.
+ * @param[in] vblank The client vblank object
+ * @param[in] sequence The target sequence number
+ * @param[in] func The user client vblank handler
+ * @param[in] user_data The user data
+ * @return #TDM_ERROR_NONE if success. Otherwise, error value.
+ */
+tdm_error
+tdm_client_vblank_wait_seq(tdm_client_vblank *vblank, unsigned int sequence, tdm_client_vblank_handler func, void *user_data);
+
+/**
+ * @brief Check if the client vblank object is waiting a vblank event
+ * @param[in] vblank The client vblank object
+ * @return 1 if waiting. 0 if not waiting.
+ */
+unsigned int
+tdm_client_vblank_is_waiting(tdm_client_vblank *vblank);
+
+/* Virtual Output */
+#include <tbm_surface.h>
+
+tdm_client_voutput *
+tdm_client_create_voutput(tdm_client *client, const char *name, tdm_error *error);
+
+void
+tdm_client_voutput_destroy(tdm_client_voutput *voutput);
+
+tdm_error
+tdm_client_voutput_set_available_modes(tdm_client_voutput *voutput, const tdm_client_output_mode *modes, int count);
+
+tdm_error
+tdm_client_voutput_set_physical_size(tdm_client_voutput *voutput, unsigned int mmWidth, unsigned int mmHeight);
+
+tdm_error
+tdm_client_voutput_add_commit_handler(tdm_client_voutput *voutput, tdm_client_voutput_commit_handler *func);
+
+tdm_error
+tdm_client_voutput_get_committed_tbm_surface(tdm_client_voutput *voutput, tbm_surface_h surface);
+
+tdm_client_output *
+tdm_client_voutput_get_client_output(tdm_client_voutput *voutput, tdm_error *error);
+
+tdm_error
+tdm_client_output_get_available_modes(tdm_client_output *output, tdm_client_output_mode **modes, int *count);
+
+tdm_error
+tdm_client_output_set_mode(tdm_client_output *output, const tdm_client_output_mode *mode);
+
+tdm_error
+tdm_client_output_connect(tdm_client_output *output);
+
+tdm_error
+tdm_client_output_disconnect(tdm_client_output *output);
+/* End of Virtual Output */