- @param DataSize The size in bytes of the Data buffer. A size of zero causes the\r
- variable to be deleted.\r
+ @param DataSize The size in bytes of the Data buffer. Unless the EFI_VARIABLE_APPEND_WRITE, \r
+ EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS, or \r
+ EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS attribute is set, a size of zero \r
+ causes the variable to be deleted. When the EFI_VARIABLE_APPEND_WRITE attribute is \r
+ set, then a SetVariable() call with a DataSize of zero will not cause any change to \r
+ the variable value (the timestamp associated with the variable may be updated however \r
+ even if no new data value is provided,see the description of the \r
+ EFI_VARIABLE_AUTHENTICATION_2 descriptor below. In this case the DataSize will not \r
+ be zero since the EFI_VARIABLE_AUTHENTICATION_2 descriptor will be populated). \r