Mathcad dlls always return a value. In looking more closely at your code, I see the confusion.
First, here's the Mathcad call I used. dummy := recordndPlay(1)
Second, because I didn't have all the files to create your dll, I made the abbreviated function:
LRESULT record_and_play(COMPLEXSCALAR * const arg, const COMPLEXSCALAR * const zahl
/*COMPLEXARRAY * const soundArray, LPCMCSTRING s*/)
//LPCCOMPLEXSCALAR ein LPCCOMPLEXSCALAR aus
{return 0;}
This function is declared incorrectly but runs fine for the following reason. In order for Mathcad to pass variables to the dll, it needs to know the argument list. That's the point of the FUNCTIONINFO structure. Here's what's going on in you case.
FUNCTIONINFO recordAndPlay =
{
// Funktionsname unter der die Funktion in MathCAD verfügbar sein soll "recordAndPlay",
// Beschreibung der Parameter (für Funktion-Einfügen Diaglogfeld)
"zahl",
// Beschreibung der Funktion (für Funktion-Einfügen Diaglogfeld)
"Die Funktion soll ein Sound aufnehmen, in einem File speicher und wiedergeben.",
// Zeiger zur programmierten Funktion
(LPCFUNCTION)record_and_play,
// Datentyp, denn die Funktion zurückgibt COMPLEX_SCALAR,
// Anzahl der Argumente, welche die Funktion übernimmt 1,
// Datentypen der Argumente {COMPLEX_SCALAR}
};
1. You've told Mathcad to create a function called recordAndPlay.
2. the next 2 items are legacy that Mathcad used to put into the insert->function dialog. Now they need to be put in a file called user_EN.xml if you care about having them show up in the insert function list. I've got an automated program to read dlls and generate that file, but I don't think PTC wants exe code posted.
3. You then tell Mathcad that the dll contains a function called record_and_play that it should call when the Mathcad worksheet calls recordAndPlay.
4. record_and_play takes a first argument of type COMPLEX_SCALAR*. This is the return value to Mathcad.
5. record_and_play takes 1 additional user supplied pointer of type const COMPLEX_SCALAR*
Now the type of pointer and whether it's const are compiler drectives. All Mathcad knows is that record_and_play should look like int record_and_play(void*, void*) with the return value being the error code. Internally, it will read the first void* as the variable coming back to Mathcad and treat it as LPCOMPLEX_SCALAR. The second void* Mathcad will supply to the dll as LPCCOMPLEXSCALAR. Since record_and_play is created above as int record_and_play(void*,void*), it ran fine for my abbreviated declaration. More generally, I think you're looking for something like int record_and_play(LPCOMPLEXARRAY ToMathcad, LPCMCSTRING Arg1FromMathcad, LPCMCSCALAR Arg2FromMathcad) which would fill in the FUNCTIONINFO structure as:
COMPLEX_ARRAY,
2,
{STRING, COMPLEX_SCALAR}
Robert
