Bugfix/code clean using gcc warnings (#371)

* Enable extra GCC warnings to discover subtle bugs

* convert c++ comments to c comments

* cleanup pedantic compiler warnings

* Compile apps with GNU89 GNU99 GNU11 and GNU17

Co-authored-by: Steve Karg <skarg@users.sourceforge.net>

ports/linux/bip-init.c

@@ -204,6 +204,7 @@ void bip_get_broadcast_address(BACNET_ADDRESS *dest)
 bool bip_set_addr(BACNET_IP_ADDRESS *addr)
 {
     /* not something we do within this driver */
+    (void)addr;
     return false;
 }
 
@@ -230,6 +231,7 @@ bool bip_get_addr(BACNET_IP_ADDRESS *addr)
 bool bip_set_broadcast_addr(BACNET_IP_ADDRESS *addr)
 {
     /* not something we do within this driver */
+    (void)addr;
     return false;
 }
 
@@ -255,6 +257,7 @@ bool bip_get_broadcast_addr(BACNET_IP_ADDRESS *addr)
 bool bip_set_subnet_prefix(uint8_t prefix)
 {
     /* not something we do within this driver */
+    (void)prefix;
     return false;
 }
 
@@ -336,7 +339,7 @@ uint16_t bip_receive(
     int max = 0;
     struct timeval select_timeout;
     struct sockaddr_in sin = { 0 };
-    BACNET_IP_ADDRESS addr = { { 0 } };
+    BACNET_IP_ADDRESS addr = { 0 };
     socklen_t sin_len = sizeof(sin);
     int received_bytes = 0;
     int offset = 0;
@@ -657,6 +660,8 @@ static void parseRoutes(struct nlmsghdr *nlHdr, struct route_info *rtInfo)
             case RTA_DST:
                 rtInfo->dstAddr = *(u_int *)RTA_DATA(rtAttr);
                 break;
+            default:
+                break;
         }
     }
 }

ports/linux/dlmstp.c

@@ -117,11 +117,11 @@ static struct timespec start;
 static int timespec_subtract(
     struct timespec *result, const struct timespec *l, const struct timespec *r)
 {
-#define NS_PER_S 1000000000 // nano-seconds per second
+#define NS_PER_S 1000000000 /* nano-seconds per second */
     struct timespec right = *r;
     int secs;
 
-    // Perform the carry for the later subtraction by updating y.
+    /* Perform the carry for the later subtraction by updating y. */
     if (l->tv_nsec < right.tv_nsec) {
         secs = (right.tv_nsec - l->tv_nsec) / NS_PER_S + 1;
         right.tv_nsec -= NS_PER_S * secs;
@@ -133,7 +133,7 @@ static int timespec_subtract(
         right.tv_sec -= secs;
     }
 
-    // Compute the time remaining. tv_nsec is certainly positive.
+    /* Compute the time remaining. tv_nsec is certainly positive. */
     result->tv_sec = l->tv_sec - right.tv_sec;
     result->tv_nsec = l->tv_nsec - right.tv_nsec;
 

ports/linux/rs485.c

@@ -632,7 +632,8 @@ void RS485_Print_Ports(void)
     bool valid_port = false;
     struct serial_struct serinfo;
 
-    // Scan through /sys/class/tty - it contains all tty-devices in the system
+    /* Scan through /sys/class/tty - 
+       it contains all tty-devices in the system */
     n = scandir(sysdir, &namelist, NULL, NULL);
     if (n < 0) {
         perror("RS485: scandir");
@@ -642,7 +643,7 @@ void RS485_Print_Ports(void)
                 strcmp(namelist[n]->d_name, ".")) {
                 snprintf(device_dir, sizeof(device_dir), "%s%s/device", sysdir,
                     namelist[n]->d_name);
-                // Stat the devicedir and handle it if it is a symlink
+                /* Stat the devicedir and handle it if it is a symlink */
                 if (lstat(device_dir, &st) == 0 && S_ISLNK(st.st_mode)) {
                     memset(buffer, 0, sizeof(buffer));
                     snprintf(device_dir, sizeof(device_dir),
@@ -651,16 +652,16 @@ void RS485_Print_Ports(void)
                         valid_port = false;
                         driver_name = basename(buffer);
                         if (strcmp(driver_name, "serial8250") == 0) {
-                            // serial8250-devices must be probed
+                            /* serial8250-devices must be probed */
                             snprintf(device_dir, sizeof(device_dir), "/dev/%s",
                                 namelist[n]->d_name);
                             fd = open(
                                 device_dir, O_RDWR | O_NONBLOCK | O_NOCTTY);
                             if (fd >= 0) {
-                                // Get serial_info
+                                /* Get serial_info */
                                 if (ioctl(fd, TIOCGSERIAL, &serinfo) == 0) {
-                                    // If device type is not PORT_UNKNOWN
-                                    // we accept the port
+                                    /* If device type is not PORT_UNKNOWN */
+                                    /* we accept the port */
                                     if (serinfo.type != PORT_UNKNOWN) {
                                         valid_port = true;
                                     }
@@ -671,7 +672,7 @@ void RS485_Print_Ports(void)
                             valid_port = true;
                         }
                         if (valid_port) {
-                            // print full absolute file path
+                            /* print full absolute file path */
                             printf("interface {value=/dev/%s}"
                                    "{display=MS/TP Capture on /dev/%s}\n",
                                 namelist[n]->d_name, namelist[n]->d_name);