When

[Soroush]

Hi,

Try this modification. (attached picture)

Remember to change the data type of "end_addr" to Unsigned 8-bit integer.

I hope this can help.

[Newguy100]

I tried it, but it doesn't work.

[Newguy100]

It is still empty

[Newguy100]

I do a return statement to see the number of characters it should return and print it to the screen. It is giving me a value which means I should be displaying something but its not. I'm not really sure y.

[Soroush]

1- Does you DLL file function correctly? Have you tested it in C environment?

2- I've noticed a minor point in your DLL c code. you defined data as: "unsigned char* data". In C there is no difference in the result of using "unsigned char* data" and "unsigned char *data", but they have different meanings. This is just a guess, but test it! change your DLL so that it has "unsigned char *data" instead of "unsigned char* data"

3- add short delays between sequence frames

Hope any of these suggestions van help.

[Newguy100]

I created an executable file in C and ran it. It prints out the message to the screen so I know the function works, but it doesn't want to return anything in Labview.

[Soroush]

All I can say is: Try the 2nd way in my last post.

unsigned char* data: is pointer data type that points to an unsigned byte and "data" is of that data type.

unsigned char *data: is unsigned char data type that "data" is its pointer.

I guess that your C code may run correctly if you use any of these type declarations, but LV may not. just try it and let us know too.

[Newguy100]

I tried that and I still get the same result.

[Soroush]

Hmmm, challenging!

one more idea

use a serial port monitoring program. such programs sniff serial port without taking it. I've used them myself and the results were amazing. in this way you can at least find if the port will be opened and closed properly. you also can monitor all data that are wriiten to/ read from the port.

you can search for such programs, but I've used this one. It is good enough. try trial version of its professional type!

I hope that it can help.........

[justnow]

Hi,soroush and Newguy100.

I tried so many times and failed so many times to use DLL returning an array pointer!

But last night I tried another way and it works.I used CIN instead of CLF.The idea was from NI's code example HERE. If you study the code it may help.Newguy100,maybe you can try CIN too.Perhaps our problems are the reason of data structure's deference between C and LV?Or the memory management of LV is a mystery.   I guess,not sure.