X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdata%2Fcasereader.c;h=a410afcbcbfab2c826735d9ef94e4daffdca10f5;hb=6fe157aa60e9eff822de37cfe1c181a942deda70;hp=1b06f42e8ab399b9b0ad4a3b76f1a3ea82a10bea;hpb=e3a9ad4500d77d1604da1fc0544e8a956dbc73e4;p=pspp

diff --git a/src/data/casereader.c b/src/data/casereader.c
index 1b06f42e8a..a410afcbcb 100644
--- a/src/data/casereader.c
+++ b/src/data/casereader.c
@@ -501,7 +501,8 @@ advance_random_reader (struct casereader *reader,
   if (new > old)
     {
       shared->min_offset = new;
-      shared->class->advance (reader, shared->aux, new - old);
+      if (shared->class->advance)
+        shared->class->advance (reader, shared->aux, new - old);
     }
 }