diff --git a/tests/abis/abis_test.c b/tests/abis/abis_test.c
index 8ba5f17..563363d 100644
--- a/tests/abis/abis_test.c
+++ b/tests/abis/abis_test.c
@@ -167,7 +167,7 @@
 	}
 }
 
-static void test_sw_descr()
+static void test_sw_descr(void)
 {
 	const char *f_id = "TEST.L0L", *f_ver = "0.1.666~deadbeeffacefeed-dirty";
 	uint8_t chain[] = { 0x42, 0x12, 0x00, 0x03, 0x01, 0x02, 0x03, 0x13, 0x00, 0x03, 0x03, 0x04, 0x05, 0x42, 0x12,
@@ -194,7 +194,7 @@
 }
 
 /* Test decode IPAC_DLCX_IND obtained from SYS#5915 */
-static void test_dec_ipac_dlc_indx()
+static void test_dec_ipac_dlc_indx(void)
 {
 /* Radio Signalling Link (RSL)
 	0111 111. = Message discriminator: ip.access Vendor Specific messages (63)
diff --git a/tests/bitvec/bitvec_test.c b/tests/bitvec/bitvec_test.c
index ea7ea9a..29c3e33 100644
--- a/tests/bitvec/bitvec_test.c
+++ b/tests/bitvec/bitvec_test.c
@@ -69,7 +69,7 @@
 	printf("         %s [%d]\n\n", lol, bv->cur_bit);
 }
 
-static void test_byte_ops()
+static void test_byte_ops(void)
 {
 	struct bitvec bv;
 	const uint8_t *in = (const uint8_t *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
@@ -162,7 +162,7 @@
 	OSMO_ASSERT(num == result);
 }
 
-static void test_array()
+static void test_array(void)
 {
 	struct bitvec b;
 	uint8_t d[4096];
@@ -181,7 +181,7 @@
 	test_array_item(17, &b, n, array, n * 3);
 }
 
-static void test_used_bytes()
+static void test_used_bytes(void)
 {
 	struct bitvec b;
 	uint8_t d[32];
@@ -204,7 +204,7 @@
 	}
 }
 
-static void test_tailroom()
+static void test_tailroom(void)
 {
 	struct bitvec b;
 	uint8_t d[32];
diff --git a/tests/bsslap/bsslap_test.c b/tests/bsslap/bsslap_test.c
index f20f7db..fc5ce75 100644
--- a/tests/bsslap/bsslap_test.c
+++ b/tests/bsslap/bsslap_test.c
@@ -48,7 +48,7 @@
 	},
 };
 
-void test_bsslap_enc_dec()
+void test_bsslap_enc_dec(void)
 {
 	struct bsslap_pdu *pdu;
 	printf("--- %s\n", __func__);
@@ -96,7 +96,7 @@
 	}
 }
 
-int main()
+int main(int argc, char **argv)
 {
 	test_bsslap_enc_dec();
 	return 0;
diff --git a/tests/bssmap_le/bssmap_le_test.c b/tests/bssmap_le/bssmap_le_test.c
index 08ed4c6..a14c38a 100644
--- a/tests/bssmap_le/bssmap_le_test.c
+++ b/tests/bssmap_le/bssmap_le_test.c
@@ -150,7 +150,7 @@
 	},
 };
 
-void test_bssmap_le_enc_dec()
+void test_bssmap_le_enc_dec(void)
 {
 	struct bssmap_le_pdu *pdu;
 	printf("--- %s\n", __func__);
@@ -200,7 +200,7 @@
 	}
 }
 
-int main()
+int main(int argc, char **argv)
 {
 	test_bssmap_le_enc_dec();
 	return 0;
diff --git a/tests/codec/codec_ecu_fr_test.c b/tests/codec/codec_ecu_fr_test.c
index 4040ce9..a9dae89 100644
--- a/tests/codec/codec_ecu_fr_test.c
+++ b/tests/codec/codec_ecu_fr_test.c
@@ -183,7 +183,7 @@
 }
 
 /* Simulate a real life situation: voice frames with a few dropouts */
-void test_fr_concealment_realistic()
+void test_fr_concealment_realistic(void)
 {
 	struct osmo_ecu_fr_state state;
 	uint8_t frame[GSM_FR_BYTES];
@@ -219,7 +219,7 @@
 }
 
 /* Simulate a real life situation: voice frames with a few dropouts, using generic core */
-void test_fr_concealment_realistic_core()
+void test_fr_concealment_realistic_core(void)
 {
 	struct osmo_ecu_state *state = osmo_ecu_init(NULL, OSMO_ECU_CODEC_FR);
 	uint8_t frame[GSM_FR_BYTES];
diff --git a/tests/ctrl/ctrl_test.c b/tests/ctrl/ctrl_test.c
index 01fb9f7..1d4d4d7 100644
--- a/tests/ctrl/ctrl_test.c
+++ b/tests/ctrl/ctrl_test.c
@@ -334,7 +334,7 @@
 	},
 };
 
-static void test_messages()
+static void test_messages(void)
 {
 	struct ctrl_handle *ctrl;
 	struct ctrl_connection *ccon;
@@ -390,7 +390,7 @@
 	return 0;
 }
 
-static void test_deferred_cmd()
+static void test_deferred_cmd(void)
 {
 	struct ctrl_handle *ctrl;
 	struct ctrl_connection *ccon;
diff --git a/tests/fr/fr_test.c b/tests/fr/fr_test.c
index 3fb18f3..cdcdb43 100644
--- a/tests/fr/fr_test.c
+++ b/tests/fr/fr_test.c
@@ -52,7 +52,7 @@
 	return fd;
 }
 
-void bssgp_prim_cb()
+void bssgp_prim_cb(void)
 {
 }
 
diff --git a/tests/fsm/fsm_dealloc_test.c b/tests/fsm/fsm_dealloc_test.c
index f4be93d..246ba56 100644
--- a/tests/fsm/fsm_dealloc_test.c
+++ b/tests/fsm/fsm_dealloc_test.c
@@ -290,7 +290,7 @@
 	obj_add_other(b, a);
 }
 
-static struct scene *scene_alloc()
+static struct scene *scene_alloc(void)
 {
 	struct scene *s = talloc_zero(ctx, struct scene);
 	s->use_count.talloc_object = s;
@@ -419,7 +419,7 @@
 	}
 }
 
-void test_osmo_fsm_term_safely()
+void test_osmo_fsm_term_safely(void)
 {
 	fprintf(stderr, "\n\n%s()\n", __func__);
 	osmo_fsm_term_safely(true);
@@ -428,7 +428,7 @@
 	fprintf(stderr, "\n\n%s() done\n", __func__);
 }
 
-void test_osmo_fsm_set_dealloc_ctx()
+void test_osmo_fsm_set_dealloc_ctx(void)
 {
 	fprintf(stderr, "\n\n%s()\n", __func__);
 	void *dealloc_ctx = talloc_named_const(ctx, 0, "fsm_dealloc");
diff --git a/tests/fsm/fsm_test.c b/tests/fsm/fsm_test.c
index 6fa0ae7..960042c 100644
--- a/tests/fsm/fsm_test.c
+++ b/tests/fsm/fsm_test.c
@@ -172,7 +172,7 @@
 	return fi;
 }
 
-static void test_id_api()
+static void test_id_api(void)
 {
 	struct osmo_fsm_inst *fi;
 
@@ -280,7 +280,7 @@
 	osmo_timers_update(); \
 } while (0)
 
-void fake_time_start()
+void fake_time_start(void)
 {
 	struct timespec *clock_override;
 
@@ -301,7 +301,7 @@
 	return 0;
 }
 
-static void test_state_chg_keep_timer()
+static void test_state_chg_keep_timer(void)
 {
 	struct osmo_fsm_inst *fi;
 
@@ -349,7 +349,7 @@
 	fprintf(stderr, "--- %s() done\n", __func__);
 }
 
-static void test_state_chg_T()
+static void test_state_chg_T(void)
 {
 	struct osmo_fsm_inst *fi;
 
diff --git a/tests/gad/gad_test.c b/tests/gad/gad_test.c
index ca8c4fa..19be6a6 100644
--- a/tests/gad/gad_test.c
+++ b/tests/gad/gad_test.c
@@ -4,7 +4,7 @@
 #include <osmocom/core/msgb.h>
 #include <osmocom/gsm/gad.h>
 
-void test_gad_lat_lon_dec_enc_stability()
+void test_gad_lat_lon_dec_enc_stability(void)
 {
 	uint32_t lat_enc;
 	uint32_t lon_enc;
@@ -49,7 +49,7 @@
 	},
 };
 
-void test_gad_enc_dec()
+void test_gad_enc_dec(void)
 {
 	int i;
 	printf("--- %s\n", __func__);
@@ -115,7 +115,7 @@
 	}
 }
 
-void test_gad_to_str()
+void test_gad_to_str(void)
 {
 	int i;
 	printf("--- %s\n", __func__);
@@ -134,7 +134,7 @@
 	}
 }
 
-int main()
+int main(int argc, char **argv)
 {
 	test_gad_lat_lon_dec_enc_stability();
 	test_gad_enc_dec();
diff --git a/tests/gb/gprs_bssgp_rim_test.c b/tests/gb/gprs_bssgp_rim_test.c
index e2d4f66..bb533f6 100644
--- a/tests/gb/gprs_bssgp_rim_test.c
+++ b/tests/gb/gprs_bssgp_rim_test.c
@@ -60,7 +60,7 @@
 	}
 }
 
-static void test_bssgp_parse_rim_ri()
+static void test_bssgp_parse_rim_ri(void)
 {
 	int rc;
 	struct bssgp_rim_routing_info result;
@@ -94,7 +94,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_create_rim_ri()
+static void test_bssgp_create_rim_ri(void)
 {
 	int rc;
 	struct bssgp_rim_routing_info ri;
@@ -194,7 +194,7 @@
 	}
 }
 
-static void test_bssgp_dec_ran_inf_req_rim_cont_nacc()
+static void test_bssgp_dec_ran_inf_req_rim_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_req_rim_cont rim_cont_dec;
@@ -212,7 +212,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_ran_inf_req_rim_cont_nacc()
+static void test_bssgp_enc_ran_inf_req_rim_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_req_rim_cont rim_cont = { };
@@ -321,7 +321,7 @@
 	}
 }
 
-static void test_bssgp_dec_ran_inf_rim_cont_nacc()
+static void test_bssgp_dec_ran_inf_rim_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_rim_cont rim_cont_dec;
@@ -346,7 +346,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_dec_ran_inf_rim_cont_err_nacc()
+static void test_bssgp_dec_ran_inf_rim_cont_err_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_rim_cont rim_cont_dec;
@@ -364,7 +364,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_ran_inf_rim_cont_nacc()
+static void test_bssgp_enc_ran_inf_rim_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_rim_cont rim_cont = { };
@@ -415,7 +415,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_ran_inf_rim_cont_err_nacc()
+static void test_bssgp_enc_ran_inf_rim_cont_err_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_rim_cont rim_cont = { };
@@ -458,7 +458,7 @@
 	}
 }
 
-static void test_bssgp_dec_ran_inf_ack_rim_cont()
+static void test_bssgp_dec_ran_inf_ack_rim_cont(void)
 {
 	int rc;
 	struct bssgp_ran_inf_ack_rim_cont rim_cont_dec;
@@ -474,7 +474,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_ran_inf_ack_rim_cont()
+static void test_bssgp_enc_ran_inf_ack_rim_cont(void)
 {
 	int rc;
 	struct bssgp_ran_inf_ack_rim_cont rim_cont = { };
@@ -513,7 +513,7 @@
 	}
 }
 
-static void test_bssgp_dec_ran_inf_err_rim_cont()
+static void test_bssgp_dec_ran_inf_err_rim_cont(void)
 {
 	int rc;
 	struct bssgp_ran_inf_err_rim_cont rim_cont_dec;
@@ -530,7 +530,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_ran_inf_err_rim_cont()
+static void test_bssgp_enc_ran_inf_err_rim_cont(void)
 {
 	int rc;
 	struct bssgp_ran_inf_err_rim_cont rim_cont = { };
@@ -578,7 +578,7 @@
 	}
 }
 
-static void test_bssgp_dec_ran_inf_app_err_rim_cont_nacc()
+static void test_bssgp_dec_ran_inf_app_err_rim_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_app_err_rim_cont rim_cont_dec;
@@ -597,7 +597,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_ran_inf_app_err_rim_cont_nacc()
+static void test_bssgp_enc_ran_inf_app_err_rim_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_app_err_rim_cont rim_cont = { };
@@ -623,7 +623,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_dec_ran_inf_req_app_cont_nacc()
+static void test_bssgp_dec_ran_inf_req_app_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_req_app_cont_nacc app_cont_dec;
@@ -639,7 +639,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_ran_inf_req_app_cont_nacc()
+static void test_bssgp_enc_ran_inf_req_app_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_req_app_cont_nacc app_cont = { };
@@ -662,7 +662,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_dec_ran_inf_app_cont_nacc()
+static void test_bssgp_dec_ran_inf_app_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_app_cont_nacc app_cont_dec;
@@ -682,7 +682,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_ran_inf_app_cont_nacc()
+static void test_bssgp_enc_ran_inf_app_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_ran_inf_app_cont_nacc app_cont = { };
@@ -721,7 +721,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_dec_app_err_cont_nacc()
+static void test_bssgp_dec_app_err_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_app_err_cont_nacc app_cont_dec;
@@ -737,7 +737,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_enc_app_err_cont_nacc()
+static void test_bssgp_enc_app_err_cont_nacc(void)
 {
 	int rc;
 	struct bssgp_app_err_cont_nacc app_cont = { };
diff --git a/tests/gb/gprs_bssgp_test.c b/tests/gb/gprs_bssgp_test.c
index 43fc056..775ae43 100644
--- a/tests/gb/gprs_bssgp_test.c
+++ b/tests/gb/gprs_bssgp_test.c
@@ -173,7 +173,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_bad_reset()
+static void test_bssgp_bad_reset(void)
 {
 	struct msgb *msg;
 	uint16_t bvci_be = htons(2);
@@ -256,7 +256,7 @@
 	printf("----- %s END\n", __func__);
 }
 
-static void test_bssgp_msgb_copy()
+static void test_bssgp_msgb_copy(void)
 {
 	struct msgb *msg, *msg2;
 	uint16_t bvci_be = htons(2);
diff --git a/tests/gb/gprs_ns_test.c b/tests/gb/gprs_ns_test.c
index 6ced6a3..fc1ec60 100644
--- a/tests/gb/gprs_ns_test.c
+++ b/tests/gb/gprs_ns_test.c
@@ -420,7 +420,7 @@
 	return rc;
 }
 
-static void test_nsvc()
+static void test_nsvc(void)
 {
 	struct gprs_ns_inst *nsi = gprs_ns_instantiate(gprs_ns_callback, NULL);
 	struct sockaddr_in peer[1] = {{0},};
@@ -459,7 +459,7 @@
 	alarm(0);
 }
 
-static void test_ignored_messages()
+static void test_ignored_messages(void)
 {
 	struct gprs_ns_inst *nsi = gprs_ns_instantiate(gprs_ns_callback, NULL);
 	struct sockaddr_in peer[1] = {{0},};
@@ -486,7 +486,7 @@
 	nsi = NULL;
 }
 
-static void test_bss_port_changes()
+static void test_bss_port_changes(void)
 {
 	struct gprs_ns_inst *nsi = gprs_ns_instantiate(gprs_ns_callback, NULL);
 	struct sockaddr_in peer[4] = {{0},};
@@ -540,7 +540,7 @@
 	nsi = NULL;
 }
 
-static void test_bss_reset_ack()
+static void test_bss_reset_ack(void)
 {
 	struct gprs_ns_inst *nsi = gprs_ns_instantiate(gprs_ns_callback, NULL);
 	struct sockaddr_in peer[4] = {{0},};
@@ -687,7 +687,7 @@
 }
 
 
-static void test_sgsn_reset()
+static void test_sgsn_reset(void)
 {
 	struct gprs_ns_inst *nsi = gprs_ns_instantiate(gprs_ns_callback, NULL);
 	struct sockaddr_in sgsn_peer= {0};
@@ -765,7 +765,7 @@
 	nsi = NULL;
 }
 
-static void test_sgsn_reset_invalid_state()
+static void test_sgsn_reset_invalid_state(void)
 {
 	struct gprs_ns_inst *nsi = gprs_ns_instantiate(gprs_ns_callback, NULL);
 	struct sockaddr_in sgsn_peer= {0};
@@ -833,7 +833,7 @@
 	nsi = NULL;
 }
 
-static void test_sgsn_output()
+static void test_sgsn_output(void)
 {
 	struct gprs_ns_inst *nsi = gprs_ns_instantiate(gprs_ns_callback, NULL);
 	struct sockaddr_in sgsn_peer= {0};
diff --git a/tests/gsm0408/gsm0408_test.c b/tests/gsm0408/gsm0408_test.c
index 38200c7..a226718 100644
--- a/tests/gsm0408/gsm0408_test.c
+++ b/tests/gsm0408/gsm0408_test.c
@@ -90,7 +90,7 @@
 	{ speech_no3a_lv, &bcap_speech_no3a, "Speech, without octet 3a" },
 };
 
-static int test_bearer_cap()
+static int test_bearer_cap(void)
 {
 	struct gsm_mncc_bearer_cap bc;
 	int i, rc;
@@ -1154,7 +1154,7 @@
 	},
 };
 
-void test_struct_mobile_identity()
+void test_struct_mobile_identity(void)
 {
 	struct mobile_identity_tc *t;
 	printf("%s()\n", __func__);
@@ -1316,7 +1316,7 @@
 	},
 };
 
-static void test_bcd_number_encode_decode()
+static void test_bcd_number_encode_decode(void)
 {
 	const struct bcd_number_test *test;
 	uint8_t buf_enc[0xff] = { 0xff };
@@ -1550,7 +1550,7 @@
 	}
 }
 
-static void test_range_encoding()
+static void test_range_encoding(void)
 {
 	int *arfcns;
 	int arfcns_num = 0;
@@ -1611,7 +1611,7 @@
 			__FILE__, __LINE__, (int) res, # cmp, (int) wanted);	\
 	}
 
-static void test_arfcn_filter()
+static void test_arfcn_filter(void)
 {
 	int arfcns[50], i, res, f0_included;
 	for (i = 0; i < ARRAY_SIZE(arfcns); ++i)
@@ -1644,7 +1644,7 @@
 		VERIFY(arfcns[i], ==, ((i + 1) * 2) - 1);
 }
 
-static void test_print_encoding()
+static void test_print_encoding(void)
 {
 	int rc;
 	int w[17];
@@ -1669,7 +1669,7 @@
 	printf("Range512: %s\n", osmo_hexdump(chan_list, ARRAY_SIZE(chan_list)));
 }
 
-static void test_si_range_helpers()
+static void test_si_range_helpers(void)
 {
 	int ws[(sizeof(freqs1)/sizeof(freqs1[0]))];
 	int i, f0 = 0xFFFFFF;
@@ -1708,7 +1708,7 @@
 	VERIFY(f0, ==, 1);
 }
 
-static void test_power_ctrl()
+static void test_power_ctrl(void)
 {
 	int8_t rc8;
 	int rc;
@@ -1750,7 +1750,7 @@
 	VERIFY(rc, <, 0);
 }
 
-static void test_rach_tx_integer_raw2val()
+static void test_rach_tx_integer_raw2val(void)
 {
 	unsigned int raw;
 	for (raw = 0; raw <= 0x0f; raw++) {
diff --git a/tests/gsm0502/gsm0502_test.c b/tests/gsm0502/gsm0502_test.c
index f4f6530..e9deaa9 100644
--- a/tests/gsm0502/gsm0502_test.c
+++ b/tests/gsm0502/gsm0502_test.c
@@ -86,7 +86,7 @@
 	502782, 502825, 502869, 502903, 502955, 502999
 };
 
-static void test_gsm0502_fn_remap()
+static void test_gsm0502_fn_remap(void)
 {
 	unsigned int i;
         uint32_t fn_begin;
diff --git a/tests/gsm0808/gsm0808_test.c b/tests/gsm0808/gsm0808_test.c
index b3aa3ab..2734f91 100644
--- a/tests/gsm0808/gsm0808_test.c
+++ b/tests/gsm0808/gsm0808_test.c
@@ -111,7 +111,7 @@
 	msgb_free(in_msg);
 }
 
-static void test_create_layer3_aoip()
+static void test_create_layer3_aoip(void)
 {
 	static const uint8_t res[] = {
 		0x00, 0x17, 0x57, 0x05, 0x08, 0x00, 0x77, 0x62,
@@ -148,7 +148,7 @@
 	msgb_free(in_msg);
 }
 
-static void test_create_reset()
+static void test_create_reset(void)
 {
 	static const uint8_t res[] = { 0x00, 0x04, 0x30, 0x04, 0x01, 0x20 };
 	struct msgb *msg;
@@ -159,7 +159,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_reset_ack()
+static void test_create_reset_ack(void)
 {
 	static const uint8_t res[] = { 0x00, 0x01, 0x31 };
 	struct msgb *msg;
@@ -171,7 +171,7 @@
 }
 
 
-static void test_create_clear_command()
+static void test_create_clear_command(void)
 {
 	static const uint8_t res[] = { 0x20, 0x04, 0x01, 0x23 };
 	struct msgb *msg;
@@ -182,7 +182,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_clear_command2()
+static void test_create_clear_command2(void)
 {
 	static const uint8_t res[] = { 0x00, 0x04, 0x20, 0x04, 0x01, 0x23 };
 	struct msgb *msg;
@@ -193,7 +193,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_clear_command2_csfb()
+static void test_create_clear_command2_csfb(void)
 {
 	static const uint8_t res[] = { 0x00, 0x05, 0x20, 0x04, 0x01, 0x23, 0x8F };
 	struct msgb *msg;
@@ -204,7 +204,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_clear_complete()
+static void test_create_clear_complete(void)
 {
 	static const uint8_t res[] = { 0x00, 0x01, 0x21 };
 	struct msgb *msg;
@@ -215,7 +215,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_cipher()
+static void test_create_cipher(void)
 {
 	static const uint8_t res[] =
 	    { 0x00, 0x0c, 0x53, 0x0a, 0x09, 0x03, 0xaa,
@@ -255,7 +255,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_cipher_complete()
+static void test_create_cipher_complete(void)
 {
 	static const uint8_t res1[] = {
 		0x00, 0x08, 0x55, 0x20, 0x03, 0x23, 0x42, 0x21, 0x2c, 0x04 };
@@ -312,7 +312,7 @@
 		       rc, exp, OSMO_BIT_PRINT(exp), msgb_hexdump(msg));
 }
 
-static void test_create_cipher_reject()
+static void test_create_cipher_reject(void)
 {
 	static const uint8_t res[] = { 0x00, 0x04, 0x59, 0x04, 0x01, 0x23 };
 	enum gsm0808_cause cause = GSM0808_CAUSE_CCCH_OVERLOAD;
@@ -327,7 +327,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_cipher_reject_ext()
+static void test_create_cipher_reject_ext(void)
 {
 	static const uint8_t res[] = { 0x00, 0x05, 0x59, 0x04, 0x02, 0xd0, 0xFA };
 	uint8_t cause = 0xFA;
@@ -342,7 +342,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_cm_u()
+static void test_create_cm_u(void)
 {
 	static const uint8_t res[] = {
 		0x00, 0x07, 0x54, 0x12, 0x01, 0x23, 0x13, 0x01, 0x42 };
@@ -364,7 +364,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_sapi_reject()
+static void test_create_sapi_reject(void)
 {
 	static const uint8_t res[] = { 0x00, 0x06, 0x25, 0x18, 0x03, 0x04, 0x01, 0x25 };
 	struct msgb *msg;
@@ -375,7 +375,7 @@
 	msgb_free(msg);
 }
 
-static void test_dec_confusion()
+static void test_dec_confusion(void)
 {
 	static const uint8_t hex[] =
 		{ 0x26, 0x04, 0x01, 0x52, 0x1f, 0x07, 0x00, 0xff, 0x00, 0x03, 0x25, 0x03, 0x25 };
@@ -425,7 +425,7 @@
 }
 
 /* Test Perform Location Report SYS#5891 */
-static void test_dec_perform_location_report_sys5891()
+static void test_dec_perform_location_report_sys5891(void)
 {
 /*	Message Type Perform Location Request
 	Location Type
@@ -477,7 +477,7 @@
 	OSMO_ASSERT(rc == 5);
 }
 
-static void test_create_ass()
+static void test_create_ass(void)
 {
 	static const uint8_t res1[] =
 	    { 0x00, 0x0a, 0x01, 0x0b, 0x04, 0x01, 0x0b, 0xa1, 0x25, 0x01, 0x00,
@@ -527,7 +527,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_ass2()
+static void test_create_ass2(void)
 {
 	static const uint8_t res[] = {
 		BSSAP_MSG_BSS_MANAGEMENT,
@@ -604,7 +604,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_ass_compl()
+static void test_create_ass_compl(void)
 {
 	static const uint8_t res1[] = {
 		0x00, 0x09, 0x02, 0x15, 0x23, 0x21, 0x42, 0x2c,
@@ -623,7 +623,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_ass_compl_aoip()
+static void test_create_ass_compl_aoip(void)
 {
 	struct sockaddr_storage ss;
 	struct sockaddr_in sin;
@@ -660,7 +660,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_ass_fail()
+static void test_create_ass_fail(void)
 {
 	static const uint8_t res1[] = { 0x00, 0x04, 0x03, 0x04, 0x01, 0x23 };
 	static const uint8_t res2[] = {
@@ -678,7 +678,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_ass_fail_aoip()
+static void test_create_ass_fail_aoip(void)
 {
 	static const uint8_t res1[] =
 	    { 0x00, 0x0d, 0x03, 0x04, 0x01, 0x23, GSM0808_IE_SPEECH_CODEC_LIST,
@@ -704,7 +704,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_clear_rqst()
+static void test_create_clear_rqst(void)
 {
 	static const uint8_t res[] = { 0x00, 0x04, 0x22, 0x04, 0x01, 0x23 };
 	struct msgb *msg;
@@ -715,7 +715,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_paging()
+static void test_create_paging(void)
 {
 	static const uint8_t res[] =
 	    { 0x00, 0x10, 0x52, 0x08, 0x08, 0x09, 0x10, 0x10, 0x00, 0x00, 0x00,
@@ -755,7 +755,7 @@
 	msgb_free(msg);
 }
 
-static void test_create_dtap()
+static void test_create_dtap(void)
 {
 	static const uint8_t res[] = { 0x01, 0x03, 0x02, 0x23, 0x42 };
 	struct msgb *msg, *l3;
@@ -772,7 +772,7 @@
 	msgb_free(l3);
 }
 
-static void test_prepend_dtap()
+static void test_prepend_dtap(void)
 {
 	static const uint8_t res[] = { 0x01, 0x03, 0x02, 0x23, 0x42 };
 	struct msgb *in_msg;
@@ -789,7 +789,7 @@
 	msgb_free(in_msg);
 }
 
-static void test_enc_dec_lcls()
+static void test_enc_dec_lcls(void)
 {
 	static const uint8_t res[] = {
 		GSM0808_IE_GLOBAL_CALL_REF,
@@ -867,7 +867,7 @@
 	msgb_free(msg);
 }
 
-static void test_enc_dec_aoip_trasp_addr_v4()
+static void test_enc_dec_aoip_trasp_addr_v4(void)
 {
 	struct sockaddr_storage enc_addr;
 	struct sockaddr_storage dec_addr;
@@ -895,7 +895,7 @@
 	msgb_free(msg);
 }
 
-static void test_enc_dec_aoip_trasp_addr_v6()
+static void test_enc_dec_aoip_trasp_addr_v6(void)
 {
 	struct sockaddr_storage enc_addr;
 	struct sockaddr_storage dec_addr;
@@ -924,7 +924,7 @@
 	msgb_free(msg);
 }
 
-static void test_enc_aoip_trasp_addr_msg_too_small()
+static void test_enc_aoip_trasp_addr_msg_too_small(void)
 {
 	struct msgb *msg;
 	struct sockaddr_storage enc_addr;
@@ -946,7 +946,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_speech_codec()
+static void test_gsm0808_enc_dec_speech_codec(void)
 {
 	struct gsm0808_speech_codec enc_sc = {
 		.pi = true,
@@ -971,7 +971,7 @@
 }
 
 
-static void test_gsm0808_enc_dec_speech_codec_with_cfg()
+static void test_gsm0808_enc_dec_speech_codec_with_cfg(void)
 {
 	struct gsm0808_speech_codec enc_sc = {
 		.pi = true,
@@ -996,7 +996,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_speech_codec_ext_with_cfg()
+static void test_gsm0808_enc_dec_speech_codec_ext_with_cfg(void)
 {
 	struct gsm0808_speech_codec enc_sc = {
 		.pi = true,
@@ -1021,7 +1021,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_speech_codec_list()
+static void test_gsm0808_enc_dec_speech_codec_list(void)
 {
 	struct gsm0808_speech_codec_list enc_scl = {
 		.codec = {
@@ -1064,7 +1064,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_empty_speech_codec_list()
+static void test_gsm0808_enc_dec_empty_speech_codec_list(void)
 {
 	struct gsm0808_speech_codec_list enc_scl = {
 		.len = 0,
@@ -1086,7 +1086,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_channel_type()
+static void test_gsm0808_enc_dec_channel_type(void)
 {
 	struct gsm0808_channel_type enc_ct = {
 		.ch_indctr = GSM0808_CHAN_SPEECH,
@@ -1117,7 +1117,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_encrypt_info()
+static void test_gsm0808_enc_dec_encrypt_info(void)
 {
 	struct gsm0808_encrypt_info enc_ei = {
 		.perm_algo = { GSM0808_ALG_ID_A5_0, GSM0808_ALG_ID_A5_1 },
@@ -1147,7 +1147,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_dec_cell_id_list_srvcc()
+static void test_gsm0808_dec_cell_id_list_srvcc(void)
 {
 	/* taken from a pcap file of a real-world 3rd party MSC (SYS#5838) */
 	const uint8_t enc_cil[] = { 0x0b, 0x2, 0xf2, 0x10, 0x4e, 0x20, 0x15, 0xbe};
@@ -1160,7 +1160,7 @@
 	OSMO_ASSERT(dec_cil.id_list_len = 1);
 }
 
-static void test_gsm0808_enc_dec_cell_id_list_lac()
+static void test_gsm0808_enc_dec_cell_id_list_lac(void)
 {
 	struct gsm0808_cell_id_list2 enc_cil;
 	struct gsm0808_cell_id_list2 dec_cil;
@@ -1187,7 +1187,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_list_single_lac()
+static void test_gsm0808_enc_dec_cell_id_list_single_lac(void)
 {
 	struct gsm0808_cell_id_list2 enc_cil;
 	struct gsm0808_cell_id_list2 dec_cil;
@@ -1216,7 +1216,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_list_multi_lac()
+static void test_gsm0808_enc_dec_cell_id_list_multi_lac(void)
 {
 	struct gsm0808_cell_id_list2 enc_cil;
 	struct gsm0808_cell_id_list2 dec_cil;
@@ -1252,7 +1252,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_list_bss()
+static void test_gsm0808_enc_dec_cell_id_list_bss(void)
 {
 	struct gsm0808_cell_id_list2 enc_cil;
 	struct gsm0808_cell_id_list2 dec_cil;
@@ -1275,7 +1275,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_list_multi_lai_and_lac()
+static void test_gsm0808_enc_dec_cell_id_list_multi_lai_and_lac(void)
 {
 	struct gsm0808_cell_id_list2 enc_cil;
 	struct gsm0808_cell_id_list2 dec_cil;
@@ -1331,7 +1331,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_list_multi_ci()
+static void test_gsm0808_enc_dec_cell_id_list_multi_ci(void)
 {
 	struct gsm0808_cell_id_list2 enc_cil;
 	struct gsm0808_cell_id_list2 dec_cil;
@@ -1365,7 +1365,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_list_multi_lac_and_ci()
+static void test_gsm0808_enc_dec_cell_id_list_multi_lac_and_ci(void)
 {
 	struct gsm0808_cell_id_list2 enc_cil;
 	struct gsm0808_cell_id_list2 dec_cil;
@@ -1406,7 +1406,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_list_multi_global()
+static void test_gsm0808_enc_dec_cell_id_list_multi_global(void)
 {
 	struct gsm0808_cell_id_list2 enc_cil;
 	struct gsm0808_cell_id_list2 dec_cil;
@@ -1479,7 +1479,7 @@
 	printf("     cell_id_list == %s\n", gsm0808_cell_id_list_name(cil));
 }
 
-void test_cell_id_list_add() {
+void test_cell_id_list_add(void) {
 	size_t zu;
 
 	const struct gsm0808_cell_id_list2 cgi1 = {
@@ -1661,7 +1661,7 @@
 	printf("------- %s done\n", __func__);
 }
 
-static void test_gsm0808_enc_dec_cell_id_lac()
+static void test_gsm0808_enc_dec_cell_id_lac(void)
 {
 	struct gsm0808_cell_id enc_ci = {
 		.id_discr = CELL_IDENT_LAC,
@@ -1687,7 +1687,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_bss()
+static void test_gsm0808_enc_dec_cell_id_bss(void)
 {
 	struct gsm0808_cell_id enc_ci = {
 		.id_discr = CELL_IDENT_BSS,
@@ -1709,7 +1709,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_no_cell()
+static void test_gsm0808_enc_dec_cell_id_no_cell(void)
 {
 	struct gsm0808_cell_id enc_ci = {
 		.id_discr = CELL_IDENT_NO_CELL,
@@ -1731,7 +1731,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_lai_and_lac()
+static void test_gsm0808_enc_dec_cell_id_lai_and_lac(void)
 {
 	struct gsm0808_cell_id enc_ci = {
 		.id_discr = CELL_IDENT_LAI_AND_LAC,
@@ -1762,7 +1762,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_ci()
+static void test_gsm0808_enc_dec_cell_id_ci(void)
 {
 	struct gsm0808_cell_id enc_ci = {
 		.id_discr = CELL_IDENT_CI,
@@ -1785,7 +1785,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_lac_and_ci()
+static void test_gsm0808_enc_dec_cell_id_lac_and_ci(void)
 {
 	struct gsm0808_cell_id enc_ci = {
 		.id_discr = CELL_IDENT_LAC_AND_CI,
@@ -1812,7 +1812,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_global()
+static void test_gsm0808_enc_dec_cell_id_global(void)
 {
 	struct gsm0808_cell_id enc_ci = {
 		.id_discr = CELL_IDENT_WHOLE_GLOBAL,
@@ -1844,7 +1844,7 @@
 	msgb_free(msg);
 }
 
-static void test_gsm0808_enc_dec_cell_id_global_ps()
+static void test_gsm0808_enc_dec_cell_id_global_ps(void)
 {
 	struct gsm0808_cell_id enc_cgi = {
 		.id_discr = CELL_IDENT_WHOLE_GLOBAL,
@@ -2130,7 +2130,7 @@
 	printf("\n");
 }
 
-void test_gsm48_mr_cfg_from_gsm0808_sc_cfg()
+void test_gsm48_mr_cfg_from_gsm0808_sc_cfg(void)
 {
 	printf("Testing gsm48_mr_cfg_from_gsm0808_sc_cfg():\n");
 
@@ -2315,7 +2315,7 @@
 	{ .id = cgi_23_042_23_5, .match_id = cgi_23_99_23_5, .expect_match = false, .expect_exact_match = false },
 };
 
-static void test_cell_id_matching()
+static void test_cell_id_matching(void)
 {
 	int i;
 	bool ok = true;
@@ -2478,7 +2478,7 @@
 	{ .id_discr = 423 },
 };
 
-static void test_gsm0808_cell_id_to_from_cgi()
+static void test_gsm0808_cell_id_to_from_cgi(void)
 {
 	int i;
 	int j;
diff --git a/tests/gsm23003/gsm23003_test.c b/tests/gsm23003/gsm23003_test.c
index e73ef43..77d3173 100644
--- a/tests/gsm23003/gsm23003_test.c
+++ b/tests/gsm23003/gsm23003_test.c
@@ -54,7 +54,7 @@
 	{ NULL, false },
 };
 
-bool test_valid_imsi()
+bool test_valid_imsi(void)
 {
 	int i;
 	bool pass = true;
@@ -97,7 +97,7 @@
 	{ NULL, false },
 };
 
-bool test_valid_msisdn()
+bool test_valid_msisdn(void)
 {
 	int i;
 	bool pass = true;
@@ -138,7 +138,7 @@
 	{ NULL, false, false },
 };
 
-bool test_valid_imei()
+bool test_valid_imei(void)
 {
 	int i;
 	bool pass = true;
@@ -185,7 +185,7 @@
 	{ "023 ", { -EINVAL, 0, false } },
 };
 
-static bool test_mnc_from_str()
+static bool test_mnc_from_str(void)
 {
 	int i;
 	bool pass = true;
@@ -209,7 +209,7 @@
 	return pass;
 }
 
-static bool test_gummei_name()
+static bool test_gummei_name(void)
 {
 	static const struct osmo_gummei gummei = {
 		.plmn = { .mcc = 901, .mnc = 70 },
@@ -226,7 +226,7 @@
 	return pass;
 }
 
-static bool test_domain_gen()
+static bool test_domain_gen(void)
 {
 	static const struct osmo_gummei gummei = {
 		.plmn = { .mcc = 901, .mnc = 70 },
@@ -252,7 +252,7 @@
 }
 
 
-static bool test_domain_parse()
+static bool test_domain_parse(void)
 {
 	static const char *mme_dom_valid = "mmec01.mmegiA001.mme.epc.mnc070.mcc901.3gppnetwork.org";
 	static const char *home_dom_valid = "epc.mnc070.mcc901.3gppnetwork.org";
diff --git a/tests/gsm23236/gsm23236_test.c b/tests/gsm23236/gsm23236_test.c
index 77e20e3..6cbdbeb 100644
--- a/tests/gsm23236/gsm23236_test.c
+++ b/tests/gsm23236/gsm23236_test.c
@@ -138,7 +138,7 @@
 	},
 };
 
-void test_nri_v_get_set()
+void test_nri_v_get_set(void)
 {
 	struct nri_v_get_set_test *t;
 
@@ -222,7 +222,7 @@
 	{ .nri = INT16_MAX, .nri_bitlen = 0, .expect_rc = 1 },
 };
 
-void test_nri_validate()
+void test_nri_validate(void)
 {
 	struct nri_validate_tc *t;
 	printf("\n%s()\n", __func__);
@@ -327,7 +327,7 @@
 
 };
 
-void test_nri_range_validate()
+void test_nri_range_validate(void)
 {
 	struct nri_range_validate_tc *t;
 	printf("\n%s()\n", __func__);
@@ -357,7 +357,7 @@
 	printf("};\n");
 }
 
-void test_nri_list()
+void test_nri_list(void)
 {
 	struct osmo_nri_ranges *nri_ranges = osmo_nri_ranges_alloc(ctx);
 	printf("\n%s()\n", __func__);
@@ -545,7 +545,7 @@
 	DEL(100, 1);
 }
 
-void test_nri_limit_by_ranges()
+void test_nri_limit_by_ranges(void)
 {
 	const uint8_t nri_bitlen = 8;
 	const int16_t expect_nri_vals[] = { 10, 20, 21, 30, 31, 32 };
@@ -594,7 +594,7 @@
 	}
 }
 
-int main()
+int main(int argc, char **argv)
 {
 	ctx = talloc_named_const(NULL, 0, "nri_test");
 
diff --git a/tests/gsm29205/gsm29205_test.c b/tests/gsm29205/gsm29205_test.c
index 5d4835b..6598f89 100644
--- a/tests/gsm29205/gsm29205_test.c
+++ b/tests/gsm29205/gsm29205_test.c
@@ -28,7 +28,7 @@
 #include <string.h>
 #include <errno.h>
 
-static void test_gcr()
+static void test_gcr(void)
 {
 	static const uint8_t res[] = {
 		0x03, /* .net_len */
diff --git a/tests/gsm48/rest_octets_test.c b/tests/gsm48/rest_octets_test.c
index fdab143..bf53212 100644
--- a/tests/gsm48/rest_octets_test.c
+++ b/tests/gsm48/rest_octets_test.c
@@ -77,7 +77,7 @@
 	},
 };
 
-static void test_si13()
+static void test_si13(void)
 {
 	int i, rc;
 	uint8_t data[GSM_MACBLOCK_LEN];
diff --git a/tests/lapd/lapd_test.c b/tests/lapd/lapd_test.c
index ab0f316..739f9b7 100644
--- a/tests/lapd/lapd_test.c
+++ b/tests/lapd/lapd_test.c
@@ -376,7 +376,7 @@
 	return 0;
 }
 
-static void test_lapdm_polling()
+static void test_lapdm_polling(void)
 {
 	printf("I do some very simple LAPDm test.\n");
 
@@ -470,7 +470,7 @@
 	lapdm_channel_exit(&ms_to_bts_channel);
 }
 
-static void test_lapdm_contention_resolution()
+static void test_lapdm_contention_resolution(void)
 {
 	printf("I test contention resultion by having two mobiles collide and "
 		"first mobile repeating SABM.\n");
@@ -523,7 +523,7 @@
 	lapdm_channel_exit(&bts_to_ms_channel);
 }
 
-static void test_lapdm_early_release()
+static void test_lapdm_early_release(void)
 {
 	printf("I test RF channel release of an unestablished channel.\n");
 
@@ -603,7 +603,7 @@
 	msgb_free(msg);
 }
 
-static void test_lapdm_establishment()
+static void test_lapdm_establishment(void)
 {
 	printf("I test RF channel establishment.\n");
 	printf("Testing SAPI3/SDCCH\n");
@@ -677,7 +677,7 @@
 	printf("\n");
 }
 
-static void test_lapdm_desync()
+static void test_lapdm_desync(void)
 {
 	printf("I test if desync problems exist in LAPDm\n");
 
diff --git a/tests/logging/logging_vty_test.c b/tests/logging/logging_vty_test.c
index f67746b..96b316d 100644
--- a/tests/logging/logging_vty_test.c
+++ b/tests/logging/logging_vty_test.c
@@ -78,7 +78,7 @@
 	return CMD_SUCCESS;
 }
 
-static void vty_commands_init()
+static void vty_commands_init(void)
 {
 	install_element_ve(&log_sweep_cmd);
 }
@@ -121,7 +121,7 @@
 	.num_cat = ARRAY_SIZE(default_categories),
 };
 
-static void print_help()
+static void print_help(void)
 {
 	printf( "options:\n"
 		"  -h	--help		this text\n"
diff --git a/tests/msgb/msgb_test.c b/tests/msgb/msgb_test.c
index bd52f9f..7966103 100644
--- a/tests/msgb/msgb_test.c
+++ b/tests/msgb/msgb_test.c
@@ -61,7 +61,7 @@
 	return *exception == 0;
 }
 
-static void test_msgb_api()
+static void test_msgb_api(void)
 {
 	struct msgb *msg = msgb_alloc_headroom(4096, 128, "data");
 	unsigned char *cptr = NULL;
@@ -117,7 +117,7 @@
 	msgb_free(msg);
 }
 
-static void test_msgb_api_errors()
+static void test_msgb_api_errors(void)
 {
 	struct msgb *msg = msgb_alloc_headroom(4096, 128, "data");
 	volatile int e = 0;
@@ -138,7 +138,7 @@
 	osmo_set_panic_handler(NULL);
 }
 
-static void test_msgb_copy()
+static void test_msgb_copy(void)
 {
 	struct msgb *msg = msgb_alloc_headroom(4096, 128, "data");
 	struct msgb *msg2;
@@ -185,7 +185,7 @@
 	msgb_free(msg2);
 }
 
-static void test_msgb_resize_area()
+static void test_msgb_resize_area(void)
 {
 	struct msgb *msg = msgb_alloc_headroom(4096, 128, "data");
 	int rc;
@@ -285,7 +285,7 @@
 	osmo_set_panic_handler(NULL);
 }
 
-static void test_msgb_printf()
+static void test_msgb_printf(void)
 {
 	struct msgb *msg;
 	struct msgb *msg_ref;
diff --git a/tests/sms/sms_test.c b/tests/sms/sms_test.c
index 9ca83a5..912c082 100644
--- a/tests/sms/sms_test.c
+++ b/tests/sms/sms_test.c
@@ -215,7 +215,7 @@
 	},
 };
 
-static void test_octet_return()
+static void test_octet_return(void)
 {
 	char out[256];
 	int oct, septets;
diff --git a/tests/smscb/cbsp_test.c b/tests/smscb/cbsp_test.c
index d530798..2dbdded 100644
--- a/tests/smscb/cbsp_test.c
+++ b/tests/smscb/cbsp_test.c
@@ -81,7 +81,7 @@
 	return msg;
 }
 
-static void test_decode()
+static void test_decode(void)
 {
 	struct msgb *msg;
 	struct osmo_cbsp_decoded *cbsp_dec;
diff --git a/tests/sockaddr_str/sockaddr_str_test.c b/tests/sockaddr_str/sockaddr_str_test.c
index 0d0674b..541c3a1 100644
--- a/tests/sockaddr_str/sockaddr_str_test.c
+++ b/tests/sockaddr_str/sockaddr_str_test.c
@@ -90,7 +90,7 @@
 	printf("{ .af = %s, .ip = %s, .port = %u }\n", af_name(oip->af), osmo_quote_str(oip->ip, -1), oip->port);
 }
 
-void sockaddr_str_test_conversions()
+void sockaddr_str_test_conversions(void)
 {
 	int i;
 	char buf[1024];
@@ -235,7 +235,7 @@
 
 }
 
-static void test_osmo_sockaddr_str_cmp()
+static void test_osmo_sockaddr_str_cmp(void)
 {
 	int i;
 	printf("\n\n%s\n", __func__);
diff --git a/tests/socket/socket_test.c b/tests/socket/socket_test.c
index fe77b92..d090fba 100644
--- a/tests/socket/socket_test.c
+++ b/tests/socket/socket_test.c
@@ -150,7 +150,7 @@
 	return 0;
 }
 
-static int test_get_ip_and_port()
+static int test_get_ip_and_port(void)
 {
 	int fd, rc;
 	char ip[INET6_ADDRSTRLEN] = { };
diff --git a/tests/stats/stats_test.c b/tests/stats/stats_test.c
index 4e36223..2796100 100644
--- a/tests/stats/stats_test.c
+++ b/tests/stats/stats_test.c
@@ -340,7 +340,7 @@
 
 #define do_report(A, B) _do_report(A, B, __LINE__)
 
-static void test_reporting()
+static void test_reporting(void)
 {
 	struct osmo_stats_reporter *srep1, *srep2, *srep;
 	struct osmo_stat_item_group *statg1, *statg2;
diff --git a/tests/tdef/tdef_test.c b/tests/tdef/tdef_test.c
index c348e69..a0fcc9a 100644
--- a/tests/tdef/tdef_test.c
+++ b/tests/tdef/tdef_test.c
@@ -125,7 +125,7 @@
 	}
 }
 
-static void test_tdef_get_nonexisting()
+static void test_tdef_get_nonexisting(void)
 {
 	printf("\n%s()\n", __func__);
 
@@ -136,7 +136,7 @@
 	print_tdef_get(tdefs, 5, OSMO_TDEF_US);
 }
 
-static void test_tdef_set_and_get()
+static void test_tdef_set_and_get(void)
 {
 	struct osmo_tdef *t;
 	printf("\n%s()\n", __func__);
@@ -317,7 +317,7 @@
 	osmo_timers_update(); \
 } while (0)
 
-void fake_time_start()
+void fake_time_start(void)
 {
 	struct timespec *clock_override;
 
diff --git a/tests/tdef/tdef_vty_config_root_test.c b/tests/tdef/tdef_vty_config_root_test.c
index aa5ff1b..e2dbcb4 100644
--- a/tests/tdef/tdef_vty_config_root_test.c
+++ b/tests/tdef/tdef_vty_config_root_test.c
@@ -111,7 +111,7 @@
 	return CMD_SUCCESS;
 }
 
-static void timer_init_vty()
+static void timer_init_vty(void)
 {
 	/* Again, this is merely to get a vty write hook, see above. */
 	install_node(&timer_node, config_write_timer);
@@ -123,7 +123,7 @@
 
 void *root_ctx = NULL;
 
-static void print_help()
+static void print_help(void)
 {
 	printf( "options:\n"
 		"  -h	--help		this text\n"
diff --git a/tests/tdef/tdef_vty_config_subnode_test.c b/tests/tdef/tdef_vty_config_subnode_test.c
index 90c7968..d4abe09 100644
--- a/tests/tdef/tdef_vty_config_subnode_test.c
+++ b/tests/tdef/tdef_vty_config_subnode_test.c
@@ -102,7 +102,7 @@
 	return CMD_SUCCESS;
 }
 
-static void gsmnet_init_vty()
+static void gsmnet_init_vty(void)
 {
 	install_node(&gsmnet_node, config_write_gsmnet);
 	install_element(CONFIG_NODE, &cfg_net_cmd);
@@ -116,7 +116,7 @@
 
 void *root_ctx = NULL;
 
-static void print_help()
+static void print_help(void)
 {
 	printf( "options:\n"
 		"  -h	--help		this text\n"
diff --git a/tests/tdef/tdef_vty_dynamic_test.c b/tests/tdef/tdef_vty_dynamic_test.c
index a181d91..715fa60 100644
--- a/tests/tdef/tdef_vty_dynamic_test.c
+++ b/tests/tdef/tdef_vty_dynamic_test.c
@@ -179,7 +179,7 @@
 	return CMD_SUCCESS;
 }
 
-static void member_init_vty()
+static void member_init_vty(void)
 {
 	install_node(&member_node, config_write_member);
 	install_element(CONFIG_NODE, &cfg_member_cmd);
@@ -190,7 +190,7 @@
 
 /* ------------------- THE REST is just boilerplate osmo main() ------------------- */
 
-static void print_help()
+static void print_help(void)
 {
 	printf( "options:\n"
 		"  -h	--help		this text\n"
diff --git a/tests/time_cc/time_cc_test.c b/tests/time_cc/time_cc_test.c
index 22ea7f6..e4a5aaf 100644
--- a/tests/time_cc/time_cc_test.c
+++ b/tests/time_cc/time_cc_test.c
@@ -125,7 +125,7 @@
 	.num_cat = ARRAY_SIZE(log_categories),
 };
 
-int main()
+int main(int argc, char **argv)
 {
 	void *ctx = talloc_named_const(NULL, 0, "time_cc_test");
 	struct timespec *now;
diff --git a/tests/tlv/tlv_test.c b/tests/tlv/tlv_test.c
index fdd15ab..f9137ad 100644
--- a/tests/tlv/tlv_test.c
+++ b/tests/tlv/tlv_test.c
@@ -188,7 +188,7 @@
 	}
 }
 
-static void test_tlv_shift_functions()
+static void test_tlv_shift_functions(void)
 {
 	uint8_t test_data[1024];
 	uint8_t buf[1024];
@@ -250,7 +250,7 @@
 /* Most GSM related protocols clearly indicate that in case of duplicate
  * IEs, only the first occurrence shall be used, while any further occurrences
  * shall be ignored.  See e.g. 3GPP TS 24.008 Section 8.6.3 */
-static void test_tlv_repeated_ie()
+static void test_tlv_repeated_ie(void)
 {
 	uint8_t test_data[768];
 	int i, rc;
@@ -288,7 +288,7 @@
 	OSMO_ASSERT(dec3[2].lv[tag].val == &test_data[2 + 3 + 3]);
 }
 
-static void test_tlv_encoder()
+static void test_tlv_encoder(void)
 {
 	const uint8_t enc_ies[] = {
 		0x17, 0x14,	0x06, 0x2b, 0x12, 0x2b, 0x0b, 0x40, 0x2b, 0xb7, 0x05, 0xd0, 0x63, 0x82, 0x95, 0x03, 0x05, 0x40,
@@ -332,7 +332,7 @@
 	msgb_free(msg);
 }
 
-static void test_tlv_parser_bounds()
+static void test_tlv_parser_bounds(void)
 {
 	struct tlv_definition tdef;
 	struct tlv_parsed dec;
@@ -423,7 +423,7 @@
 	OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
 }
 
-static void test_tlv_lens()
+static void test_tlv_lens(void)
 {
 	uint16_t buf_len;
 	uint8_t buf[512];
diff --git a/tests/use_count/use_count_test.c b/tests/use_count/use_count_test.c
index 2942c69..b784aeb 100644
--- a/tests/use_count/use_count_test.c
+++ b/tests/use_count/use_count_test.c
@@ -192,7 +192,7 @@
 	return foo;
 }
 
-void print_foos()
+void print_foos(void)
 {
 	int count = 0;
 	struct foo *foo;
@@ -204,7 +204,7 @@
 	fprintf(stderr, "%d foos\n\n", count);
 }
 
-static void test_use_count_fsm()
+static void test_use_count_fsm(void)
 {
 	struct foo *a, *b, *c;
 	log("\n%s()\n", __func__);
diff --git a/tests/utils/utils_test.c b/tests/utils/utils_test.c
index 3ac5d1e..9ddae65 100644
--- a/tests/utils/utils_test.c
+++ b/tests/utils/utils_test.c
@@ -342,7 +342,7 @@
 	{ "DeafBeddedBabeAcceededFadedDecaff", 32, 32, false, false },
 };
 
-bool test_is_hexstr()
+bool test_is_hexstr(void)
 {
 	int i;
 	bool pass = true;
@@ -1023,7 +1023,7 @@
 };
 
 
-static void osmo_str_tolowupper_test()
+static void osmo_str_tolowupper_test(void)
 {
 	int i;
 	char buf[128];
@@ -1197,7 +1197,7 @@
 	return sb.chars_needed;
 }
 
-void strbuf_test()
+void strbuf_test(void)
 {
 	char buf[256];
 	int rc;
@@ -1230,7 +1230,7 @@
 	printf("(need %d chars, had size=63) %s\n", rc, buf);
 }
 
-void strbuf_test_nolen()
+void strbuf_test_nolen(void)
 {
 	char buf[20];
 	struct osmo_strbuf sb = { .buf = buf, .len = sizeof(buf) };
@@ -1256,7 +1256,7 @@
 		printf("   ERROR: EXPECTED %s\n", expect_rc ? "true" : "false");
 }
 
-static void startswith_test()
+static void startswith_test(void)
 {
 	printf("\n%s()\n", __func__);
 	startswith_test_str(NULL, NULL, true);
@@ -1301,7 +1301,7 @@
         OSMO_NAME_C_IMPL(ctx, 0, NULL, foo_name_buf, arg)
 }
 
-static void name_c_impl_test()
+static void name_c_impl_test(void)
 {
 	char *test_strs[] = {
 		"test",
@@ -1703,7 +1703,7 @@
 		return "";
 	}
 }
-void test_float_str_to_int()
+void test_float_str_to_int(void)
 {
 	const struct float_str_to_int_test *t;
 	printf("--- %s\n", __func__);
@@ -1865,7 +1865,7 @@
 	{ 23, -9223372036854775807, "-0.00009223372036854775807" },
 	{ 23, INT64_MIN, "-ERR" },
 };
-void test_int_to_float_str()
+void test_int_to_float_str(void)
 {
 	const struct int_to_float_str_test *t;
 	printf("--- %s\n", __func__);
@@ -1956,7 +1956,7 @@
 	{ "123 ", 10, -1000, 1000, -E2BIG, 123 },
 	{ "123.4", 10, -1000, 1000, -E2BIG, 123 },
 };
-void test_str_to_int()
+void test_str_to_int(void)
 {
 	const struct str_to_int_test *t;
 	printf("--- %s\n", __func__);
@@ -2053,7 +2053,7 @@
 	{ "-9223372036854775809", 10, -1000, 1000, -EOVERFLOW, INT64_MIN },
 	{ "9223372036854775808", 10, -1000, 1000, -EOVERFLOW, INT64_MAX },
 };
-void test_str_to_int64()
+void test_str_to_int64(void)
 {
 	const struct str_to_int64_test *t;
 	printf("--- %s\n", __func__);
diff --git a/tests/vty/vty_test.c b/tests/vty/vty_test.c
index 3076a70..01e323e 100644
--- a/tests/vty/vty_test.c
+++ b/tests/vty/vty_test.c
@@ -476,7 +476,7 @@
 	return CMD_SUCCESS;
 }
 
-void test_vty_add_cmds()
+void test_vty_add_cmds(void)
 {
 	install_element(CONFIG_NODE, &cfg_ret_warning_cmd);
 	install_element(CONFIG_NODE, &cfg_ret_success_cmd);
@@ -507,7 +507,7 @@
 	install_element_ve(&cfg_range_baseboth_cmd);
 }
 
-void test_is_cmd_ambiguous()
+void test_is_cmd_ambiguous(void)
 {
 	struct vty *vty;
 	struct vty_test test;
@@ -526,7 +526,7 @@
 	destroy_test_vty(&test, vty);
 }
 
-void test_numeric_range()
+void test_numeric_range(void)
 {
 	struct vty *vty;
 	struct vty_test test;
@@ -541,7 +541,7 @@
 	destroy_test_vty(&test, vty);
 }
 
-void test_ranges()
+void test_ranges(void)
 {
 	struct vty *vty;
 	struct vty_test test;
diff --git a/tests/vty/vty_transcript_test.c b/tests/vty/vty_transcript_test.c
index 84664f9..0f18f7e 100644
--- a/tests/vty/vty_transcript_test.c
+++ b/tests/vty/vty_transcript_test.c
@@ -37,7 +37,7 @@
 
 void *root_ctx = NULL;
 
-static void print_help()
+static void print_help(void)
 {
 	printf( "options:\n"
 		"  -h	--help		this text\n"
@@ -315,7 +315,7 @@
 	return CMD_SUCCESS;
 }
 
-static void init_vty_cmds()
+static void init_vty_cmds(void)
 {
 	install_element_ve(&single0_cmd);
 	install_element_ve(&multi0_cmd);