INT_FAST64_MAX undefined

Hi Guys,

I am trying to use INT_FAST64_MAX in our codeline but it is giving me
symbol undeclared.

INT_FAST64_MAX is included in /usr/include/stdint.h but is under the
condition -

--------------------------------
/* The ISO C99 standard specifies that in C++ implementations these
   macros should only be defined if explicitly requested.  */
#if !defined __cplusplus || defined __STDC_LIMIT_MACROS
--------------------------------

Can someone please provide me pointers as to how I can make this macro
available.

Test code -

#include <stdio.h>
#include <stdint.h>

int main()
{
#if defined INT_FAST64_MAX
        printf("Available\n");
#else
        printf("Not Available\n");
#endif
        return(0);
}

Binary perpared -
g++ test.cpp

Run -
./a.out
Not Available

Regards,
Tushar