Enforce prototypes on functions

This is the first warning we actually enforce. Hopefully, many more will
follow.

coap/er-coap-13/er-coap-13.c

@@ -463,7 +463,7 @@ coap_get_variable(const uint8_t *buffer, size_t length, const char *name, const
 
 /*-----------------------------------------------------------------------------------*/
 uint16_t
-coap_get_mid()
+coap_get_mid(void)
 {
   return ++current_mid;
 }

core/packet.c

@@ -123,7 +123,7 @@ bool lwm2m_set_coap_block_size(const uint16_t coap_block_size_arg) {
     return false;
 }
 
-uint16_t lwm2m_get_coap_block_size() { return coap_block_size; }
+uint16_t lwm2m_get_coap_block_size(void) { return coap_block_size; }
 
 static void handle_reset(lwm2m_context_t * contextP,
                          void * fromSessionH,

examples/client/lwm2mclient.c

@@ -776,7 +776,7 @@ static void update_bootstrap_info(lwm2m_client_state_t * previousBootstrapState,
     }
 }
 
-static void close_backup_object()
+static void close_backup_object(void)
 {
     int i;
     for (i = 0; i < BACKUP_OBJECT_COUNT; i++) {

examples/client/object_device.c

@@ -631,7 +631,7 @@ void display_device_object(lwm2m_object_t * object)
     }
 }
 
-lwm2m_object_t * get_object_device()
+lwm2m_object_t * get_object_device(void)
 {
     /*
      * The get_object_device function create the object itself and return a pointer to the structure that represent it.

examples/client/system_api.c

@@ -55,7 +55,7 @@ void init_value_change(lwm2m_context_t * lwm2m)
 {
 }
 
-void system_reboot()
+void system_reboot(void)
 {
     exit(1);
 }

examples/lightclient/object_device.c

@@ -262,7 +262,7 @@ static uint8_t prv_device_execute(lwm2m_context_t * contextP,
     return COAP_405_METHOD_NOT_ALLOWED;
 }
 
-lwm2m_object_t * get_object_device()
+lwm2m_object_t * get_object_device(void)
 {
     /*
      * The get_object_device function create the object itself and return a pointer to the structure that represent it.

examples/lightclient/object_security.c

@@ -199,7 +199,7 @@ static uint8_t prv_security_read(lwm2m_context_t * contextP,
     return result;
 }
 
-lwm2m_object_t * get_security_object()
+lwm2m_object_t * get_security_object(void)
 {
     lwm2m_object_t * securityObj;
 

examples/lightclient/object_server.c

@@ -432,7 +432,7 @@ static uint8_t prv_server_create(lwm2m_context_t * contextP,
     return result;
 }
 
-lwm2m_object_t * get_server_object()
+lwm2m_object_t * get_server_object(void)
 {
     lwm2m_object_t * serverObj;
 

tests/block1tests.c

@@ -149,7 +149,7 @@ static struct TestTable table[] = {
     {NULL, NULL},
 };
 
-CU_ErrorCode create_block1_suit() {
+CU_ErrorCode create_block1_suit(void) {
     CU_pSuite pSuite = NULL;
     pSuite = CU_add_suite("Suite_block1", NULL, NULL);
 

tests/block2tests.c

@@ -98,7 +98,7 @@ static struct TestTable table[] = {
     {NULL, NULL},
 };
 
-CU_ErrorCode create_block2_suit() {
+CU_ErrorCode create_block2_suit(void) {
     CU_pSuite pSuite = NULL;
     pSuite = CU_add_suite("Suite_block2", NULL, NULL);
 

tests/convert_numbers_test.c

@@ -462,7 +462,7 @@ static struct TestTable table[] = {
         { NULL, NULL },
 };
 
-CU_ErrorCode create_convert_numbers_suit()
+CU_ErrorCode create_convert_numbers_suit(void)
 {
    CU_pSuite pSuite = NULL;
 

tests/tests.h

@@ -26,16 +26,16 @@ struct TestTable {
 };
 
 CU_ErrorCode add_tests(CU_pSuite pSuite, struct TestTable* testTable);
-CU_ErrorCode create_uri_suit();
-CU_ErrorCode create_tlv_suit();
-CU_ErrorCode create_object_read_suit();
-CU_ErrorCode create_convert_numbers_suit();
-CU_ErrorCode create_tlv_json_suit();
-CU_ErrorCode create_block1_suit();
+CU_ErrorCode create_uri_suit(void);
+CU_ErrorCode create_tlv_suit(void);
+CU_ErrorCode create_object_read_suit(void);
+CU_ErrorCode create_convert_numbers_suit(void);
+CU_ErrorCode create_tlv_json_suit(void);
+CU_ErrorCode create_block1_suit(void);
 CU_ErrorCode create_block2_suit(void);
 #ifdef LWM2M_SUPPORT_SENML_JSON
-CU_ErrorCode create_senml_json_suit();
+CU_ErrorCode create_senml_json_suit(void);
 #endif
-CU_ErrorCode create_er_coap_parse_message_suit();
+CU_ErrorCode create_er_coap_parse_message_suit(void);
 
 #endif /* TESTS_H_ */

tests/tlv_json_lwm2m_data_test.c

@@ -449,7 +449,7 @@ static struct TestTable table[] = {
         { NULL, NULL },
 };
 
-CU_ErrorCode create_tlv_json_suit()
+CU_ErrorCode create_tlv_json_suit(void)
 {
    CU_pSuite pSuite = NULL;
 

tests/tlvtests.c

@@ -46,7 +46,7 @@ static void test_tlv_free(void)
    lwm2m_data_free(10, dataP);
 }
 
-static void test_decodeTLV()
+static void test_decodeTLV(void)
 {
     uint8_t data1[] = {0xC3, 55, 1, 2, 3};
     uint8_t data2[] = {0x28, 2, 3, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
@@ -89,7 +89,7 @@ static void test_decodeTLV()
     CU_ASSERT_EQUAL(length, 0x190)
 }
 
-static void test_tlv_parse()
+static void test_tlv_parse(void)
 {
     // Resource 55 {1, 2, 3}
     uint8_t data1[] = {0xC3, 55, 1, 2, 3};
@@ -157,7 +157,7 @@ static void test_tlv_parse()
     lwm2m_data_free(result, dataP);
 }
 
-static void test_tlv_serialize()
+static void test_tlv_serialize(void)
 {
     int result;
     lwm2m_data_t *dataP;
@@ -494,7 +494,7 @@ static struct TestTable table[] = {
         { NULL, NULL },
 };
 
-CU_ErrorCode create_tlv_suit()
+CU_ErrorCode create_tlv_suit(void)
 {
    CU_pSuite pSuite = NULL;
 

tests/unittests.c

@@ -50,7 +50,7 @@ CU_ErrorCode add_tests(CU_pSuite pSuite, struct TestTable* testTable)
     return CUE_SUCCESS;
 }
 
-int main()
+int main(void)
 {
    /* initialize the CUnit test registry */
    if (CUE_SUCCESS != CU_initialize_registry())

tests/uritests.c

@@ -379,7 +379,7 @@ static struct TestTable table[] = {
         { NULL, NULL },
 };
 
-CU_ErrorCode create_uri_suit()
+CU_ErrorCode create_uri_suit(void)
 {
    CU_pSuite pSuite = NULL;
 

wakaama.cmake

@@ -124,6 +124,11 @@ add_compile_options(
     -pedantic
 )
 
+# Turn certain warnings into errors
+add_compile_options(
+    -Werror=strict-prototypes
+)
+
 # The maximum buffer size that is provided for resource responses and must be respected due to the limited IP buffer.
 # Larger data must be handled by the resource and will be sent chunk-wise through a TCP stream or CoAP blocks. Block
 # size is set to 1024 bytes if not specified otherwise to avoid block transfers in common use cases.