calling c function that return a string

[davico]

Hallo,

I found an example for calling void c function(https://forums.ni.com/t5/Example-Code/Calling-a-C-built-DLL-in-LabVIEW-to-Generate-and-Sort-an-Array...). I could adapt the example and make the function return an integer. the code of the adapted function would look like this:

int __declspec(dllexport) multiply(int number)

{

return number*3;

}

But I have problems when I want to return a string. Does someone knows how I should do. I tried:

char* __declspec(dllexport) say(int number)

{

return "hallo";

} 

but won't compile.

[Yamaeda]

I haven't worked with C-connections or dll's much, but technically you're not returning a string, but a character pointer. As such you get the adress where the string starts as an integer. You'll need to typecast the int-adress to a string.

Check your code when running and i'm sure the C-call returns a 32-bit int alot bigger than a normal character.

/Y

[nathand]

---

davico wrote:

but won't compile.

---

Are you asking a C question, or a LabVIEW question?  What's the error message?

[davico]

yes the question was  more a c question then a labview question. I found the solution anyway, the correct code in order to get string is:

_declspec(dllexport) char* testchar2();

_declspec(dllexport) char* testchar2()

{

      return "hallo";

}