diff --git a/src/vnet/pg/output.c b/src/vnet/pg/output.c
index b5ee157..d8059fa 100644
--- a/src/vnet/pg/output.c
+++ b/src/vnet/pg/output.c
@@ -79,7 +79,7 @@
     }
   if (pif->pcap_file_name != 0)
     pcap_write (&pif->pcap_main);
-  if (pif->pcap_main.file_descriptor >= 0
+  if ((pif->pcap_main.flags & PCAP_MAIN_INIT_DONE)
       && pif->pcap_main.n_packets_captured >=
       pif->pcap_main.n_packets_to_capture)
     pcap_close (&pif->pcap_main);