C#/FSUIPC Articifial Horizon Bank newbie problem

[Avi]

Hello, this is my first post in this forum, but from what i've seen before, it seems like a nice place to be..

However, I'm experimenting with FSUIPC and C# to get it to export values from the Artificial Horizontal to a C# program, and this is what I've got:

		public double GetHSIBank()
		{
			token = 0;
			dwResult = 0;
			dwOffset = 0x2F78;
			dwSize = 8;
			result = f.FSUIPC_Read(dwOffset, dwSize, ref token, ref dwResult);
			//TODO: Error handling
			result = f.FSUIPC_Process(ref dwResult);
			//TODO: Error handling
			result = f.FSUIPC_Get(ref token, ref dwResult);
			//TODO: Error handling
			return dwResult;
		}

With this code I get strange values like 1443357819 and such.

I know the code shouldn't work either, since it's a 8 bit float value being stored into an int, (It's a total ripoff of the ASI example), but I can't just figure out the right way to do it.

If someone gave me a hint/sample on how it's supposed to be done it would be a lot of help.

Thanks in advance.[/code]

[Pete Dowson]

I know the code shouldn't work either, since it's a 8 bit float value being stored into an int

Not only can it not work, but it could easily crash the program, since the FSUIPC read will read 8 bytes (you've told it to) but will store them in a 4 byte area. The excess 4 bytes will trample on something else.

(It's a total ripoff of the ASI example), but I can't just figure out the right way to do it.

I don't know C# at all, but why not simply read an 8-byte double floating point value into an 8-byte double floating point variable. Isn't that logical? I cannot see why that would not be obvious?

Regards,

Pete

[Avi]

thanks for taking your time pete,

as far as I understand, there's no overload of FSUIPC_Get() in the C# SDK that supports ref double, so would it be a better idea to read it into a byte[8] array and converting it to a double?

[Pete Dowson]

as far as I understand, there's no overload of FSUIPC_Get() in the C# SDK that supports ref double, so would it be a better idea to read it into a byte[8] array and converting it to a double?

Ah, C++/C#-speak! ;-) Sorry, terms like "overload" (even "ref".which I assumed meant "the address of" or "a pointer to") are lost on me. I'm strictly C and ASM.

But if you mean there's no way of passing a pointer to a double (which seems odd), then I suppose you could pass a pointer to any 8-byte entity, like a "long long" ("_int64") or a DWORD array[2], etc etc, then cast it into a double. Can you cast in C#?

You shouldn't really need "conversion" as such, as the value is actually in floating point format -- conversion sounds like (and usually means) actual alteration to the bit pattern, which would be wrong.

I suspect you need to talk to someone who knows C# before this gets too confusing!

Regards,

Pete

[Avi]

alright, thanks for the hints, I will take a look into it and report back with my findings tomorrow :)

[Avi]

got it to work cleanly now :)

		

public double GetHSIBank()
		{
			byte[] HSI = {0, 0, 0, 0, 0, 0, 0, 0};
			double HSID = 0;
			token = 0;
			dwResult = 0;

			result = f.FSUIPC_Read(0x2f78, 8, ref token, ref dwResult);
			result = f.FSUIPC_Process(ref dwResult);
			result = f.FSUIPC_Get(ref token, 8, ref HSI);
			//TODO: Error handling
			HSID = System.BitConverter.ToDouble(HSI, 0);
			return HSID;
		}

Quite simple, reading the data into a byte array and converting it to double.

[Pete Dowson]

got it to work cleanly now :)

...

Quite simple, reading the data into a byte array and converting it to double.

Good. Not that I understand why it is that complicated to transfer a double as a double. I'm spoiled by C's transparency I suppose.

Regards,

Pete