C#•17mo ago

❔ Need help with C#/C++ interop

I have a C++ dll (that I can't change or port to C#) that exports this function

void func(const unsigned char* in, unsigned char* out, int size)

void func(const unsigned char* in, unsigned char* out, int size)

I have some C# code that obtains a size, creates an input byte[] array holding "size" bytes of data and then creates an output byte[] array with new byte[size]. How would I declare my C++ function in C# and how would I then call it (passing in the byte arrays and size so the C++ dll gets what it expects, i.e. a pair of pointers to raw bytes it can read from and write to plus the size of those arrays)

4 Replies

ero•17mo ago

[DllImport("")]
static extern void func(byte[] @in, byte[] @out, int size);

[DllImport("")]
static extern void func(byte[] @in, byte[] @out, int size);

pretty straight forward to be more correct though, maybe

[DllImport("")]
static extern void Func(byte* @in, byte* @out, int size);

[DllImport("")]
static extern void Func(byte* @in, byte* @out, int size);

Jonathan WilsonOP•17mo ago

Ok thanks.

nukleer bomb•17mo ago

Also you can use refs to avoid unsafe context and specify data direction:

[DllImport("")]
static exrern void Func(in byte @in, ref byte @out, int size);

[DllImport("")]
static exrern void Func(in byte @in, ref byte @out, int size);

Accord•17mo ago

Looks like nothing has happened here. I will mark this as stale and this post will be archived until there is new activity.

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❔ Need help with C#/C++ interop