diff --git a/dive.c b/dive.c
index 45b50b72d..0216a75ac 100644
--- a/dive.c
+++ b/dive.c
@@ -145,6 +145,20 @@ void update_event_name(struct dive *d, struct event *event, char *name)
 	free(remove);
 }
 
+void add_extra_data(struct divecomputer *dc, const char *key, const char *value)
+{
+	struct extra_data **ed = &dc->extra_data;
+
+	while (*ed)
+		ed = &(*ed)->next;
+	*ed = malloc(sizeof(struct extra_data));
+	if (*ed) {
+		(*ed)->key = strdup(key);
+		(*ed)->value = strdup(value);
+		(*ed)->next = NULL;
+	}
+}
+
 /* this returns a pointer to static variable - so use it right away after calling */
 struct gasmix *get_gasmix_from_event(struct event *ev)
 {
diff --git a/dive.h b/dive.h
index 71275a244..dffdc4ebe 100644
--- a/dive.h
+++ b/dive.h
@@ -690,6 +690,7 @@ extern void add_gas_switch_event(struct dive *dive, struct divecomputer *dc, int
 extern struct event *add_event(struct divecomputer *dc, int time, int type, int flags, int value, const char *name);
 extern void remove_event(struct event *event);
 extern void update_event_name(struct dive *d, struct event* event, char *name);
+extern void add_extra_data(struct divecomputer *dc, const char *key, const char *value);
 extern void per_cylinder_mean_depth(struct dive *dive, struct divecomputer *dc, int *mean, int *duration);
 extern int get_cylinder_index(struct dive *dive, struct event *ev);
 extern int nr_cylinders(struct dive *dive);