Sets security descriptor on the service to the specified structure. The method returns an integer value that can be interpreted ...

Sets security descriptor on the service to the specified structure. 
The method returns an integer value that can be interpreted as follows: 
0 - Successful completion.
2 - The user does not have access to the requested information.
8 - Unknown failure.
9 - The user does not have adequate privileges.
21 - The specified parameter is invalid.
Other - For integer values other than those listed above, refer to Win32 error code documentation.