/*Show the POSIX version */

//#define _POSIX_SOURCE
//#define _POSIX_C_SOURCE         199309L  use for POSIX1 and 1b systems
#include <iostream.h>
#include <unistd.h>

int main()      {
      #ifdef _POSIX_VERSION
        cout <<"System conforms to POSIX: "
          << _POSIX_VERSION <<endl;
      #else
        cout <<"POSIX version is undefined." <<endl;
      #endif

        return 0;
}