Forcing a singleton to be treated as a SAFEARRAY

I have a C# method that I want to call from MATLAB that takes as input an array of 'int32's (int[] in C#). The signature in MATLAB is like this:

MyMethod = handle MyMethod(handle, SafeArray(int32))

Sometimes I want the input array to only have one element. This is causing me problems since, whereas I can pass a matrix with multiple elements as a SAFEARRAY, if I have a 1x1 matrix it gives me an error, presumably because it's being passed as type int32 and not SafeArray(int32).

Is there any way I can create in MATLAB a SAFEARRAY with only one element? I can work around this issue by padding a 1x1 matrix with a dummy element, but I'd prefer to do it the right way.

Answer 1

[Martijn]

The default data conversion rules for MATLAB's COM interface convert all non-scalar MATLAB arrays into 2-dimensional SAFEARRAYs.

Beginning with MATLAB 7.0.4 (R14SP2) it is possible to work around the default data conversion rule and have MATLAB convert a MATLAB array into a single dimensional SAFEARRAY. You can pass data to ActiveX servers as one-dimensional arrays by executing the following command at the MATLAB prompt:

feature('COM_SafeArraySingleDim', 1)

After executing this command, MATLAB will convert any single column matrix to a 1 dimensional array when passed to a COM object.

On a whole different note though, since MATLAB 7.9 (R2009b) you can directly call .NET Assemblies so you do not have to call them through a COM Interface anymore:

http://www.mathworks.com/help/techdoc/matlab_external/brpb5k6.html

[James King]

The problem is that I want to pass a singleton as a SafeArray. I have no problems passing a column vector as a one-dimensional SafeArray.

That other link is very helpful though; thanks!