Convert the initial portion of the string pointed to by nptr to
    an unsigned __int64 integer. strtoull is a synonym for strtouq.

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <stdlib.h>

      unsigned __int64 strtouq  (const char *nptr, char **endptr, int base);

      unsigned __int64 strtoull  (const char *nptr, char **endptr, int base);