Error while creating SAFEARRAY using Windows Rust crate.

Question

Error while creating SAFEARRAY using Windows Rust crate.

Sanil Raut 0 Microsoft Employee

Hi,
I am trying to create a safearray of type BSTR and add one BSTR Variant to it with windows rust crate: https://github.com/microsoft/windows-rs (windows = "0.48.0")

pub fn createSafeArray() {
    unsafe {
        let mut var = VARIANT::default();
        (*var.Anonymous.Anonymous).vt = VT_BSTR;
        (*var.Anonymous.Anonymous).Anonymous.bstrVal =
                ManuallyDrop::new(BSTR::from("3"));

        // Create SAFEARRAY of type BSTR
        /*
        let safearray = SafeArrayCreate(
            Com::VT_BSTR,
            1,
            &SAFEARRAYBOUND {
                cElements: 1,
                lLbound: 0,
            },
        ); */

        let safearray = SafeArrayCreateVector(VT_BSTR, 0, 1);

        // Add to safe array
        let res = SafeArrayPutElement(
            safearray,
            0 as _,
            &test as *const Com::VARIANT as *const c_void,
        );
        
        println!("Res: {:#?}", res);

    }
}

And getting the following error

Err(
    Error {
        code: HRESULT(0x80070057),
        message: "The parameter is incorrect.",
    },
)

Is there anything wrong or missing in the above code?

Viorel 122.5K Reputation points

2023-09-11T18:08:04.3966667+00:00
What is test?

Try something like this:

let mut test = SysAllocString( "text"); let res = SafeArrayPutElement( safearray, 0 as _, test as *const c_void, );

The last argument of SafeArrayPutElement should be a BSTR, which can be created by SysAllocString.

Sanil Raut 0 Microsoft Employee

@Viorel Getting the same error with

        let mut test = SysAllocString( w!("text"));
        //let mut test = BSTR::from("text");

        let mut safearray = SafeArrayCreateVector(VT_BSTR, 0, 1);

        // Add to safe array
        let res = SafeArrayPutElement(
            safearray,
            0 as _,
            (& mut test as *const _) as *const _,
        );
        
        println!("Res: {:#?}", res);

Viorel 122.5K Reputation points

2023-09-11T19:10:38.8466667+00:00

I think that the last argument of SafeArrayPutElement should be the value of the test, not its address.
Sanil Raut 0 Reputation points Microsoft Employee

2023-09-11T19:22:01.41+00:00

@Viorel
last argument that you have mentioned:
"test as *const c_void"

gives the following error:
non-primitive cast: BSTR as *const c_void
Sanil Raut 0 Reputation points Microsoft Employee

2023-09-11T19:23:40.68+00:00

@Viorel
Last argument that you have mentioned:
test as *const c_void

gives error:
non-primitive cast: BSTR as *const c_void
Viorel 122.5K Reputation points

2023-09-11T19:41:00.7733333+00:00
In C you can write:

SAFEARRAY* safearray = SafeArrayCreateVector( VT_BSTR, 0, 1 ); BSTR test = SysAllocString( L"text" ); LONG i[] = { 0 }; HRESULT r = SafeArrayPutElement( safearray, i, test );

You should find the right expression for the last argument in Rust.

In addition, check the definition of SafeArrayPutElement in Rust. If it is an array of indices, then define such array. It should contain a single element (0). Or pass the address of an integer variable that contains 0.
Jeanine Zhang-MSFT 11,356 Reputation points Microsoft External Staff

2023-09-15T08:33:00.7+00:00

Have you got any updates about this issue? Could you please check Viorel's suggestion?

1 answer

Your answer

Viorel 122.5K Reputation points

2023-09-11T18:08:04.3966667+00:00

What is test?

Try something like this:

let mut test = SysAllocString( "text"); let res = SafeArrayPutElement( safearray, 0 as _, test as *const c_void, );

The last argument of SafeArrayPutElement should be a BSTR, which can be created by SysAllocString.
Sanil Raut 0 Reputation points Microsoft Employee

2023-09-11T19:04:46.8566667+00:00

@Viorel Getting the same error with

let mut test = SysAllocString( w!("text")); //let mut test = BSTR::from("text"); let mut safearray = SafeArrayCreateVector(VT_BSTR, 0, 1); // Add to safe array let res = SafeArrayPutElement( safearray, 0 as _, (& mut test as *const _) as *const _, ); println!("Res: {:#?}", res);
Viorel 122.5K Reputation points

2023-09-11T19:10:38.8466667+00:00

I think that the last argument of SafeArrayPutElement should be the value of the test, not its address.
Sanil Raut 0 Reputation points Microsoft Employee

2023-09-11T19:22:01.41+00:00

@Viorel
last argument that you have mentioned:
"test as *const c_void"

gives the following error:
non-primitive cast: BSTR as *const c_void
Sanil Raut 0 Reputation points Microsoft Employee

2023-09-11T19:23:40.68+00:00

@Viorel
Last argument that you have mentioned:
test as *const c_void

gives error:
non-primitive cast: BSTR as *const c_void
Viorel 122.5K Reputation points

2023-09-11T19:41:00.7733333+00:00

In C you can write:

SAFEARRAY* safearray = SafeArrayCreateVector( VT_BSTR, 0, 1 ); BSTR test = SysAllocString( L"text" ); LONG i[] = { 0 }; HRESULT r = SafeArrayPutElement( safearray, i, test );

You should find the right expression for the last argument in Rust.

In addition, check the definition of SafeArrayPutElement in Rust. If it is an array of indices, then define such array. It should contain a single element (0). Or pass the address of an integer variable that contains 0.
Jeanine Zhang-MSFT 11,356 Reputation points Microsoft External Staff

2023-09-15T08:33:00.7+00:00

Have you got any updates about this issue? Could you please check Viorel's suggestion?

Answer 1

Kenny Kerr 0 Microsoft Employee

Here's an example: https://github.com/microsoft/windows-rs/issues/2648#issuecomment-1715813708

Share via

Error while creating SAFEARRAY using Windows Rust crate.

1 answer

Your answer