assign port_id_minimum to a value

Author: songmeo

libcanard/canard.c

@@ -81,6 +81,7 @@ typedef uint16_t TransferCRC;
 #define CRC_INITIAL 0xFFFFU
 #define CRC_RESIDUE 0x0000U
 #define CRC_SIZE_BYTES 2U
+#define PORT_ID_MINIMUM 49152
 
 #if (CANARD_CRC_TABLE != 0)
 static const uint16_t CRCTable[256] = {
@@ -1387,10 +1388,9 @@ int8_t canardRxSubscribe(struct CanardInstance* const       ins,
     int8_t       out = -CANARD_ERROR_INVALID_ARGUMENT;
     const size_t tk  = (size_t) transfer_kind;
 
-    assert(port_id >= 49152 && port_id <= 65535);
-    if (port_id < 49152 || port_id > 65535)
+    if (port_id < PORT_ID_MINIMUM)  // port_id can't be over 65535 because it exceeds type unsigned short maximum value.
     {
-        fprintf(stderr, "Invalid port: %d. Port should be within 49152 to 65535\n", port_id);
+        (void) fprintf(stderr, "Invalid port: %d. Port should be within 49152 to 65535\n", port_id);
         exit(EXIT_FAILURE);
     }
     if ((ins != NULL) && (out_subscription != NULL) && (tk < CANARD_NUM_TRANSFER_KINDS))