how to call a C# function, foo(out byte [])? -- help passing a byte pointer
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Been struggling to call the following function in a C# dll:
public bool GetLatestBuffer(out byte[] buffer)
I've allocated the buffer in Matlab and tried various castings with libpointer, but keep getting the result:
No method 'GetLatestBuffer' with matching signature found for class ...
I could write a wrapper in C# that allocates the buffer ... but would rather do the memory management in Matlab.
My pseudocode is basically:
NET.addAssembly(dllLoc)
ls = luma_ns.Luma(initParams);
ls.function1(params) % --> it works passing parameters by value
buf = zeros(10000,'uint8'); % tried uint16, int16, etc.
pbuf = libpointer('uint8Ptr',buf);
ls.GetLatestBuffer(pbuf) % doesn't match the prototype of out byte []
No method 'GetLatestBuffer' with matching signature found for class 'Luma_ns.Luma'.
Thanks!!
采纳的回答
Hi,
have you tried calling it like this
[bool_val, byte_array] = obj.GetLatestBuffer();
This works fine for me in 14a with the following example
C#
public bool GetLatestBuffer(out byte[] Buffer)
{
Buffer = new byte[10];
for (int i = 0; i < 10;i++)
{
Buffer[i] = (byte)i;
}
return true;
}
ML:
>> a = ClassLibrary1.Class1
a =
Class1 with no properties.
>> [bool,array] = a.GetLatestBuffer()
bool =
1
array =
Byte[] with properties:
Length: 10
LongLength: 10
Rank: 1
SyncRoot: [1x1 System.Byte[]]
IsReadOnly: 0
IsFixedSize: 1
IsSynchronized: 0
>>
SideNote: The out keyword forces the routine GetLatestBuffer to assign Buffer to some value. So you do NOT need to pass down a preallocated array and since you dont need to do this it appears as output in MATLAB directly.
Also in C# when using OUT you never pass down a preallocated array. So what MATLAB does is correct here and matches the .NET programming.
更多回答（2 个）
James Tursa
2014-6-5
Have you tried changing the header signature to something more friendly to MATLAB, but have the same basic I/O? E.g.,
bool GetLatestBuffer(char *buffer);
3 个评论
daniel rasnow
2014-6-6
James Tursa
2014-6-6
Don't recompile. Just create a new header file off to the side for MATLAB to use. I.e., copy the actual header h file to a new file, modify that new file by changing the signature of the function in question, then use that new header h file for calllib in MATLAB.
Friedrich
2014-7-22
This wont work because that is the .NET interface he is using and not loadlibrary!!!!
Anthony
2014-7-17
Hi,
You can create a byte[] like this:
A = NET.createArray('System.Byte',4).
Then you just have to pass it to your function.
Hope it helps,
Anthony
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