Arduino Deprecated conversion from string constant to 'char*' [-Wwrite-strings] - arduino

Question

I am getting this deprecated conversion error when I compile/verify or upload my codes to the Arduino board.
#define SENSOR 3
#define BUZZER 4
#define RELAY 5
#define MOTOR 6
char phonenumber[] = "[phone]";
//char phonenumber[] = "[phone]";
uint8_t vibrationData = 0;
uint8_t isArmed = 1;
float latitude, longitude, speed_kph, heading, altitude;
long randNumber;
void setup() {
Serial.begin(115200);
pinMode(RELAY, OUTPUT);
pinMode(MOTOR, OUTPUT);
pinMode(BUZZER, OUTPUT);
digitalWrite(RELAY, HIGH);
digitalWrite(MOTOR, HIGH);
digitalWrite(BUZZER, HIGH);
randomSeed(analogRead(A0));
attachInterrupt(digitalPinToInterrupt(SENSOR), vibrationISR, RISING);
setupFona();
disarm();
Serial.println("Setup done!");
latitude = 14.7042209;
longitude = 121.0369513;
deleteMessages();
}
void vibrationISR() {
if(!isArmed) return;
if(vibrationData == 2) return;
vibrationData = 1;
}
void loop() {
if(isArmed) {
if(vibrationData > 0) {
vibrationData = 2;
digitalWrite(BUZZER, LOW);
Serial.println("Vibration Detected");
if(sendSMS(phonenumber, "Vibration sensor triggered")) {
Serial.println("Send notification success!");
} else {
Serial.println("Send notification failed");
}
delay(1000);
digitalWrite(BUZZER, HIGH);
vibrationData = 0;
}
}
String response = readSMS(phonenumber);
if(response.equals("!#disarm")) {
disarm();
} else if(response.equals("!#arm")) {
arm();
} else if(response.equals("!#on")) {
motorOn();
} else if(response.equals("!#off")) {
motorOff();
} else if(response.equals("!#gps")) {
sendGPS();
}
}
void sendGPS() {
if(getGPS(&latitude, &longitude, &speed_kph, &heading, &altitude)) {
Serial.println("Got GPS fix");
} else {
randNumber = random(300);
if (randNumber % 2 == 0) {
latitude += 0.0001;
longitude += 0.0001;
} else {
latitude -= 0.0001;
longitude -= 0.0001;
}
Serial.println("Cannot get GPS fix");
Serial.print(latitude, 6); Serial.print(","); Serial.println(longitude, 6);
}
String message = "!#location:" + String(latitude, 6) + "," + String(longitude, 6);
Serial.println(message);
int messageLen = message.length();
char messageArray[messageLen + 1];
message.toCharArray(messageArray, messageLen + 1);
if(sendSMS(phonenumber, messageArray)) {
Serial.println("Send GPS success!");
} else {
Serial.println("Send GPS failed");
}
}
void arm() {
Serial.println("Arm");
isArmed = 1;
digitalWrite(RELAY, HIGH);
digitalWrite(MOTOR, HIGH);
if(sendSMS(phonenumber, "System is armed")) {
Serial.println("Send Arm notification success!");
} else {
Serial.println("Send Arm notification failed");
}
}
void disarm() {
Serial.println("Disarm");
isArmed = 0;
digitalWrite(RELAY, LOW);
if(sendSMS(phonenumber, "System is disamred")) {
Serial.println("Send Disarm notification success!");
} else {
Serial.println("Send Disarm notification failed");
}
}
void motorOn() {
Serial.println("Motor On");
digitalWrite(MOTOR, LOW);
if(sendSMS(phonenumber, "Motor is now on")) {
Serial.println("Send Motor On notification success!");
} else {
Serial.println("Send Motor On notification failed");
}
}
void motorOff() {
Serial.println("Motor Off");
digitalWrite(MOTOR, HIGH);
if(sendSMS(phonenumber, "Motor is now off")) {
Serial.println("Send Motor Off notification success!");
} else {
Serial.println("Send Motor Off notification failed");
}
}
Error logs:
E:\smart-motorcycle\smart-motorcycle.ino:145:47: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
if(sendSMS(phonenumber, "Motor is now off")) {
^
This codes has been tested before but after importing the project from another laptop this errors appeared.

Answer 1

Your sendSMS probably looks like this
void sendSMS(char *phonenumber, char *message);
This should be const char * when you are passing string literals.
void sendSMS(const char *phonenumber, const char *message);
note that you don't get a warning on the phone number as the array is not a pointer to const memory.
char phonenumber[] = "[phone]";