diff --git a/openbsc/tests/gbproxy/gbproxy_test.c b/openbsc/tests/gbproxy/gbproxy_test.c
index 0d14d21..aa909ef 100644
--- a/openbsc/tests/gbproxy/gbproxy_test.c
+++ b/openbsc/tests/gbproxy/gbproxy_test.c
@@ -945,7 +945,7 @@
 	gbcfg.core_mcc = 123;
 	gbcfg.core_mnc = 456;
 	gbcfg.core_apn = talloc_zero_size(NULL, 100);
-	gbcfg.core_apn_size = gprs_str_to_apn(gbcfg.core_apn, "foo.bar", 100);
+	gbcfg.core_apn_size = gprs_str_to_apn(gbcfg.core_apn, 100, "foo.bar");
 
 	configure_sgsn_peer(&sgsn_peer);
 	configure_bss_peers(bss_peer, ARRAY_SIZE(bss_peer));