ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]:

Hello guys can anyone help me out?

char *DS3231::getDOWStr(uint8_t format)
{
	char *output = "xxxxxxxxxx";
	char *daysLong[]  = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
	char *daysShort[] = {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
	Time t;
	t=getTime();
	if (format == FORMAT_SHORT)
		output = daysShort[t.dow-1];
	else
		output = daysLong[t.dow-1];
	return output;
}

char *DS3231::getMonthStr(uint8_t format)
{
	char *output= "xxxxxxxxx";
	char *monthLong[]  = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
	char *monthShort[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
	Time t;
	t=getTime();
	if (format == FORMAT_SHORT)
		output = monthShort[t.mon-1];
	else
		output = monthLong[t.mon-1];
	return output;
}

Error message:

C:\Users\okury\Documents\Arduino\libraries\DS3231\DS3231.cpp:276:99: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

You don't want to be returning a pointer to a local - they go invalid awfully quickly.

(Didn't the warning message point directly at your problem? Why didn't you share that?)

Normally, you wouldn't bother initialising this pointer like this.