UDT passed to a DLL

[markuno]

Hi folks, I must be stupid or something. I can't get the following
very simple code to work. Any help would be greatly appreciated as I can't find the answer. Regards, Mark ([email protected])
P.S The stuff below this line pastes straight into a .BAS file.
==============================================

'I expect the following output from Sub CreateRecords...
' 1
' 2
'A Variable Length String
' 3
' 4
' 5
'Another Variable Length String
' 6

Type RECORD
A As Double
B As Long
C As String
D As Long
End Type

Global Recs(1 To 2) As RECORD

Declare Sub DLLDillon Lib "\Chappel.23\Source\C\Useful23\Debug\useful23.dll" (TwoRecords As RECORD)

Sub CreateRecords()
Recs(1).C = "A Variable Length String"
Recs(2).C = "Another Variable Length String"
Call DLLDillon(Recs(1))

Debug.Print Recs(1).A
Debug.Print Recs(1).B
Debug.Print Recs(1).C
Debug.Print Recs(1).D
Debug.Print Recs(2).A
Debug.Print Recs(2).B
Debug.Print Recs(2).C
Debug.Print Recs(2).D
End Sub


'My attempt at the 'C' end follows...

'struct RECORD
'{
' double a;
' long b;
' long c;
' long d;
'};

'VOID FAR PASCAL DLLDillon(struct RECORD FAR* Recs)
'{
' Recs[0].a = 1;
' Recs[0].b = 2;
' //Recs[0].c = Don't even touch field 'c'
' Recs[0].d = 3;
' Recs[1].a = 4;
' Recs[1].b = 5;
' //Recs[0].c = Don't even touch field 'c'
' Recs[1].d = 6;
'}

[CornedBee]

What's the problem?
Try to use (ByVal pRecords as Long) as parameters in the declare statement. Then pass VarPtr(Recs(1)) as argument. On the C side nothing changes.
C side: FAR and PASCAL are not used anymore. In VC++, PASCAL is replaced by __stdcall, other compilers will have similar things. FAR is not needed in 32-bit environments.

[parksie]

__stdcall == WINAPI, and is the more general across compilers.

What I don't get is MS's love of having lots of names for EXACTLY THE SAME SODDING TYPE!

*rant over*

[kedaman]

Originally posted by parksie
__stdcall == WINAPI, and is the more general across compilers.

What I don't get is MS's love of having lots of names for EXACTLY THE SAME SODDING TYPE!

*rant over*

Layering parksie layering what if microsoft wanted to change a datatype? Then they'd have to take the complaints of all programmers that would need to change it in every single little app.

[parksie]

Still doesn't explain why there's STDCALL, WINAPI, CALLBACK, PASCAL, and most likely others as well for what is essentially __stdcall.

(However, they still do stupid things like typedef float FLOAT )

[kedaman]

same datatype for different purposes, you'll learn to know what it means in BORK

[CornedBee]

WINAPI and CALLBACK were different things in Win16...

And imagine a win32 compiler that doesn't know __stdcall (a gcc port maybe). This could be helped by simply adding one line in the sdk headers
#ifdef THIS_IS_MY_OWN_COMPILER
#define WINAPI _my_weird_stdcall_name
#endif

And everything will be compiled as it should...