Getting error message 'DS3231 clock' redeclared as different kind of symbol'

Hello, I am trying to learn about Ds3231 RTC module on my nodemcu board
I am using Jarzebski library but its showing the bellow error msg. I have also attach the ino file. Thank you

DS3231_simple:12:8: error: ‘DS3231 clock’ redeclared as different kind of symbol

DS3231 clock;

^

In file included from C:\Users\seamr\Documents\ArduinoData\packages\esp8266\hardware\esp8266\2.7.4/tools/sdk/libc/xtensa-lx106-elf/include/stdlib.h:11:0,

from C:\Users\seamr\Documents\ArduinoData\packages\esp8266\hardware\esp8266\2.7.4\cores\esp8266/Arduino.h:27,

from sketch\DS3231_simple.ino.cpp:1:

C:\Users\seamr\Documents\ArduinoData\packages\esp8266\hardware\esp8266\2.7.4/tools/sdk/libc/xtensa-lx106-elf/include/…/include/time.h:50:19: error: previous declaration of ‘clock_t clock()’

clock_t _EXFUN(clock, (void));

^

C:\Users\seamr\Documents\ArduinoData\packages\esp8266\hardware\esp8266\2.7.4/tools/sdk/libc/xtensa-lx106-elf/include/_ansi.h:65:30: note: in definition of macro ‘_EXFUN’

#define _EXFUN(name, proto) name proto

^

DS3231_simple:13:1: error: ‘RTCDateTime’ does not name a type

RTCDateTime dt;

^

C:\Users\seamr\Documents\Arduino\libraries\Arduino-DS3231-master\DS3231_simple\DS3231_simple.ino: In function ‘void setup()’:

DS3231_simple:21:9: error: request for member ‘begin’ in ‘clock’, which is of non-class type ‘clock_t() {aka long unsigned int()}’

clock.begin();

^

DS3231_simple:24:9: error: request for member ‘setDateTime’ in ‘clock’, which is of non-class type ‘clock_t() {aka long unsigned int()}’

clock.setDateTime(DATE, TIME);

^

C:\Users\seamr\Documents\Arduino\libraries\Arduino-DS3231-master\DS3231_simple\DS3231_simple.ino: In function ‘void loop()’:

DS3231_simple:29:3: error: ‘dt’ was not declared in this scope

dt = clock.getDateTime();

^

DS3231_simple:29:14: error: request for member ‘getDateTime’ in ‘clock’, which is of non-class type ‘clock_t() {aka long unsigned int()}’

dt = clock.getDateTime();

^

Multiple libraries were found for “DS3231.h”

Used: C:\Users\seamr\Documents\Arduino\libraries\DS3231

Not used: C:\Users\seamr\Documents\Arduino\libraries\Arduino-DS3231-master

exit status 1

‘DS3231 clock’ redeclared as different kind of symbol

DS3231_simple.ino (946 Bytes)

I guess that the variable "clock" is now used deep in the ESP8266 core.

Change this

DS3231 clock ;

to

DS3231 clock1 ;

then the other references to clock also in your sketch to clock1 also.

clock() is a standard C function declared in <time.h>.