Don't crash when looping over pictures for a null dive

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/dive.h b/dive.h
index 0ff22e607..737278181 100644
--- a/dive.h
+++ b/dive.h
@@ -291,8 +291,9 @@ struct picture {
 	struct picture *next;
 };
 
-#define FOR_EACH_PICTURE( DIVE ) \
-	for(struct picture *picture = DIVE->picture_list; picture; picture = picture->next)
+#define FOR_EACH_PICTURE(_dive) \
+	if (_dive)              \
+		for (struct picture *picture = (_dive)->picture_list; picture; picture = picture->next)
 
 
 extern struct picture *alloc_picture();