Calling a C++ function with void* parameter in a C# app

Question

I have a c++ function that look like this :

int Compression::DecompressPacket(const void* inData, int inLength, void* outData, int outLength)
{
    int headerLength = ComputeDataHeaderLength(inData);
    return DecompressDataContent(static_cast<const unsigned char*>(inData) + headerLength, inLength - headerLength, outData, outLength);
}

The fonction is inside a class which is inside a c++ library.

In the other hand, I need to call this fonction on my c# application. The fonction ask me to enter parameters of types : "void*, int, void*, int".

When I try to make a void* in an unsafe function,

unsafe private void lstbox_packets_SelectedIndexChanged(object sender, EventArgs e)
{
   [...]
   byte[] value = byteValuePackets[lstbox_packets.SelectedIndices[0]];    
   void* pValue = &value;
   [...]
}

I get the error :

Error 8 Cannot take the address of, get the size of, or declare a pointer to a managed type ('byte[]')

I'm not very familiar with c++ and pointer but how i am suppose to pass a void* type in c# ?

Anton Savin · Accepted Answer · 2016-03-28 23:43:37Z

2

You shouldn't take the address of value, and also you have to use fixed statement:

fixed (void* pValue = value)
{
    //...
}

answered Mar 28, 2016 at 23:43

Anton Savin

41.5k8 gold badges58 silver badges95 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Eli Algranti Over a year ago

Here's the link for the reference to fixed: msdn.microsoft.com/en-us/library/…

Eli Algranti Over a year ago

Sorry, you are right. The styling on the fixed keyword did not make it apparent it is also a link :)

Collectives™ on Stack Overflow

Calling a C++ function with void* parameter in a C# app

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related