Translates the HDF5 type type to an HDF5 string representation of the
datatype. The returned string can be one of:
H5T_STD_I8BE, H5T_STD_I8LE, H5T_STD_I16BE, H5T_STD_I16LE,
H5T_STD_I32BE, H5T_STD_I32LE, H5T_STD_I64BE, H5T_STD_I64LE,
H5T_STD_U8BE, H5T_STD_U8LE, H5T_STD_U16BE, H5T_STD_U16LE,
H5T_STD_U32BE, H5T_STD_U32LE, H5T_STD_U64BE, H5T_STD_U64LE,
H5T_NATIVE_SCHAR, H5T_NATIVE_UCHAR, H5T_NATIVE_SHORT,
H5T_NATIVE_USHORT, H5T_NATIVE_INT, H5T_NATIVE_UINT,
H5T_NATIVE_LONG, H5T_NATIVE_ULONG, H5T_NATIVE_LLONG,
H5T_NATIVE_ULLONG, H5T_IEEE_F32BE, H5T_IEEE_F32LE,
H5T_IEEE_F64BE, H5T_IEEE_F64LE, H5T_NATIVE_FLOAT,
H5T_NATIVE_DOUBLE, H5T_NATIVE_LDOUBLE, H5T_STRING or
H5T_COMPOUND.
Returns the string representation upon success, otherwise NULL.