#include <MySQL_Connection.h>
#include <MySQL_Cursor.h>
#include <ESP8266WiFi.h>  //Use this for WiFi instead of Ethernet.h


byte mac_addr[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress server_addr();   //IP of the MySQL server here
char user[] = "";               //MySQL user login username
char password[] = "!";         //MySQL user login password

// WiFi card example
char ssid[] = "";     //your SSID
char pass[] = "";       // your SSID Password


WiFiClient client;             //Use this for WiFi instead of EthernetClient
MySQL_Connection conn((Client *)&client);

//rgb 센서 변수 선언
int s0=3; // S0 는 D3
int s1=4; // S1 는 D4
int s2=5; // S2 는 D5
int s3=6; // S3 는 D6
int out=2; // OUT 은 D2
int flag=0;
byte counter=0;
byte countR=0,countG=0,countB=0;
byte TCCR2A , TCCR2B , TCNT2 , TIMSK2;

void setup() {
  Serial.begin(115200);
  while (!Serial);  //wait for serial port to connect. Needed for Leonardo only
  pinMode(s0,OUTPUT);
  pinMode(s1,OUTPUT);
  pinMode(s2,OUTPUT);
  pinMode(s3,OUTPUT);

 //Begin WiFi section
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, pass);
  while( WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
//  print out info about the connection
 
    Serial.println("Connected to network");
    Serial.print("My IP address is ");
    Serial.println(WiFi.localIP());
  
//  End WiFi section

  Serial.println("Connecting...");
  if (conn.connect(server_addr, 3307, user, password)) {
    delay(1000);
    MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);
    cur_mem->execute(INSERT_SQL);
    delete cur_mem;
  }
  else{
    Serial.println("Connection failed.");
  }
  conn.close();
}

//RGT TCS 함수
void TCS()
{
 flag=0;
 digitalWrite(s1,HIGH);
 digitalWrite(s0,HIGH);
 digitalWrite(s2,LOW);
 digitalWrite(s3,LOW);
 attachInterrupt(0, ISR_INTO, CHANGE);
 timer0_init();
}

//ISR_INTO()함수
void ISR_INTO()
{
 counter++;
}

// TIMER INIT() 함수
 void timer0_init(void)
{
  TCCR2A=0x00;
  TCCR2B=0x07;   //the clock frequency source 1024 points
  TCNT2= 100;    //10 ms overflow again
  TIMSK2 = 0x01; //allow interrupt
}
// ISR 함수
int i=0;
ISR(TIMER2_OVF_vect) {
    TCNT2=100;
    flag++;
   if(flag==1)
      {
        countR=counter;
        Serial.print("red=");
        Serial.println(countR,DEC);
        digitalWrite(s2,HIGH);
        digitalWrite(s3,HIGH);
      }
    else if(flag==2)
    {
        countG=counter;
        Serial.print("green=");
        Serial.println(countG,DEC);
        digitalWrite(s2,LOW);
        digitalWrite(s3,HIGH);
    }
   else if(flag==3)
    {
          countB=counter;
          Serial.print("blue=");
          Serial.println(countB,DEC);
          Serial.println("\n");
          digitalWrite(s2,LOW);
          digitalWrite(s3,LOW);
    }
    else if(flag==4)
     {
     flag=0;
     }
       counter=0;
}

void loop() {
  
  if (conn.connect(server_addr, 3307, user, password)) {
    delay(5000);
    MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);
    cur_mem->execute(INSERT_SQL);
    delete cur_mem;
  }
  else{
    Serial.println("Connection failed.");
  }
  conn.close();

  TCS();
  while(1);
}

아두이노 rgb센서를 이용하여 rgb값을 wifi 로 보내주는 코드를 짜는 중입니다. 

ISR 이쪽 줄에서

exit status 1

Compilation error: expected constructor, destructor, or type conversion before '(' token

이라는 오류가 뜨는데, 혹시 어떻게 해결해야 할까요.

보드는 nodeMCU 1.0 사용 , WIFI는 ESP8266WIFI 사용하고 있습니다.