diff --git a/t/pmc/socket_ipv6.t b/t/pmc/socket_ipv6.t
index 0c6a882..cbd3280 100644
--- a/t/pmc/socket_ipv6.t
+++ b/t/pmc/socket_ipv6.t
@@ -43,7 +43,7 @@ IPv6-related tests for the Socket PMC.
 
     sock = new 'Socket'
     sock.'socket'(.PIO_PF_INET6, .PIO_SOCK_STREAM, .PIO_PROTO_TCP)
-    addrinfo = sock.'getaddrinfo'(null_string, 1234, .PIO_PROTO_TCP, .PIO_PF_INET6, 0)
+    addrinfo = sock.'getaddrinfo'(null_string, 1234, .PIO_PROTO_TCP, .PIO_PF_INET6, 1)
 
     # output addresses for debugging
     it = iter addrinfo
@@ -73,7 +73,7 @@ IPv6-related tests for the Socket PMC.
     sock.'close'()
 
     sock.'socket'(.PIO_PF_INET, .PIO_SOCK_STREAM, .PIO_PROTO_TCP)
-    addrinfo = sock.'getaddrinfo'(null_string, 1234, .PIO_PROTO_TCP, .PIO_PF_INET, 0)
+    addrinfo = sock.'getaddrinfo'(null_string, 1234, .PIO_PROTO_TCP, .PIO_PF_INET, 1)
     sock.'bind'(addrinfo)
 
     str = sock.'local_address'()
diff --git a/t/pmc/testlib/test_server_ipv6.pir b/t/pmc/testlib/test_server_ipv6.pir
index 7e39f80..cd8fba1 100644
--- a/t/pmc/testlib/test_server_ipv6.pir
+++ b/t/pmc/testlib/test_server_ipv6.pir
@@ -28,7 +28,7 @@ in case of test failures.
 
     sock = new 'Socket'
     sock.'socket'(.PIO_PF_INET6, .PIO_SOCK_STREAM, .PIO_PROTO_TCP)
-    address = sock.'getaddrinfo'(null_string, 1234, .PIO_PROTO_TCP, .PIO_PF_INET6, 0)
+    address = sock.'getaddrinfo'(null_string, 1234, .PIO_PROTO_TCP, .PIO_PF_INET6, 1)
     sock.'bind'(address)
     sock.'listen'(5)