RTEST(fitsSInt, fits_sint_p)
RTEST(fitsSLong, fits_slong_p)
RTEST(fitsSShort, fits_sshort_p)
RTEST(fitsUInt, fits_uint_p)
RTEST(fitsULong, fits_ulong_p)
RTEST(fitsUShort, fits_ushort_p)