Question

I’d like to create an enumeration for ACCESS_MASK i have to use with P/Invoke, but i do not know what would be the best way for such an inplementation.

1. If it were possible:

[Flags]
enum ACCESS_MASK : uint
{
    STANDARD_RIGHTS_REQUIRED = 0x000F0000,
    SYNCHRONIZE = 0x00100000,
    // Everything reused in the specific rights ...
}

[Flags]
enum PROCESS_ACCESS_MASK : ACCESS_MASK
{
    // ...
    PROCESS_ALL_ACCESS = STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | 0xFFFF,
}

2. Everything in one: (No automatic string representation possible)

[Flags]
enum ACCESS_MASK : uint
{
    STANDARD_RIGHTS_REQUIRED = 0x000F0000,
    SYNCHRONIZE = 0x00100000,
    // ...
    PROCESS_ALL_ACCESS = STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | 0xFFFF,
}

3. Split and rewrite: (Muuuuch duplicate code)

[Flags]
enum PROCESS_ACCESS_MASK : uint
{
    STANDARD_RIGHTS_REQUIRED = 0x000F0000,
    SYNCHRONIZE = 0x00100000,
    // ...
    PROCESS_ALL_ACCESS = STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | 0xFFFF,
}

4. Split and take from basic: (Specific enum doesn’t know anything about the basic values itself)

[Flags]
enum ACCESS_MASK : uint
{
    STANDARD_RIGHTS_REQUIRED = 0x000F0000,
    SYNCHRONIZE = 0x00100000,
    // Everything reused in the specific rights ...
}

[Flags]
enum PROCESS_ACCESS_MASK : uint
{
    // ...
    PROCESS_ALL_ACCESS = ACCESS_MASK.STANDARD_RIGHTS_REQUIRED | ACCESS_MASK.SYNCHRONIZE | 0xFFFF,
}

Which option do you prefer, or are there any better ways for an ACCESS_MASK implementation?

Btw: whats a 0x100001 file access?

Edit: I know there is no enumeration inheritance and ACCESS_MASK : uint is nothing like that, but the imaginary PROCESS_ACCESS_MASK : ACCESS_MASK would be.

Answer 1

Assuming that you are hiding the P/Invoke details from the rest of the application, and that the ACCESS_MASK values are only used very locally, I’d just put all options into one single enum – your option 2.

Additionally, I’d mark the enum with FlagsAttribute to indicate that it is treated as a bit field.