Calling PB DLLs from other languages - Long Integer datatype

[Wayne Diamond]

The following source code demonstrates at its simplest how to send and receive long integers from a DLL created with PB\DLL, called from various different languages.
The DLL has just one function - PBFUNCTION, which accepts two parameters. The first parameter is the "sent" number, which you provide. When the function is invoked, the DLL will set the second parameter to 2 times the value of the first parameter, so this is the out or "receive" parameter. A better name for this function would be MultiplyByTwo instead of PBFUNCTION.
I would like to specially thank Semen Matusovski and Tom Hanlin for steering me in the right direction with these other bizarre languages
Also a special thanks to Sven Blumenstein for his excellent MASM32 version, cheers!
Please feel free to post demo calling code from other languages!

[b]'PBDLL.BAS - The Powerbasic DLL we want to call from other languages[/b]
#COMPILE DLL "pbdll.dll"
 
FUNCTION LibMain(BYVAL hInstance   AS LONG, _
                 BYVAL fwdReason   AS LONG, _
                 BYVAL lpvReserved AS LONG) EXPORT AS LONG
         LibMain = 1   'success!
END FUNCTION
 
FUNCTION PBFUNCTION (BYREF NumberIn AS LONG, BYREF NumberOut AS LONG) EXPORT AS INTEGER
 MSGBOX "PBFUNCTION(" & TRIM$(STR$(NumberIn)) & ", " & TRIM$(STR$(NumberOut)) & ") called!"
 NumberOut = NumberIn * 2   'Return the number received multiplied by 2
 FUNCTION = 1               'Return 1 to indicate the functions success
END FUNCTION

[This message has been edited by Wayne Diamond (edited September 18, 2001).]

[Wayne Diamond]

'[b]CALLPB.BAS - Call the DLL from Powerbasic[/b]
#COMPILE EXE "callpb.exe"
 
DECLARE FUNCTION PBFUNCTION Lib "pbdll.dll" ALIAS "PBFUNCTION" (BYREF NumberIn AS LONG, BYREF NumberOut AS LONG) AS LONG
 
FUNCTION PBMAIN()
 Dim NumIn AS LONG, NumOut AS LONG, CallFunction AS INTEGER
 NumIn = 10
 CallFunction = PBFUNCTION(NumIn, NumOut)
 IF CallFunction = 1 THEN
    MSGBOX "NumIn = " & STR$(NumIn) & ", NumOut is now " & TRIM$(STR$(NumOut)) & " (should be twice the value of NumIn)"
 ELSE
    MSGBOX "Call failed"
 END IF
END FUNCTION

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[Wayne Diamond]

'[b]CALLVB.FRM - Call the DLL from Visual Basic[/b]
Private Declare Function PBFUNCTION Lib "pbdll.dll" (ByRef NumberIn As Long, ByRef NumberOut As Long) As Long
  
Private Sub Form_Load()
 Dim NumIn As Long, NumOut As Long, CallFunction As Integer
 NumIn = 10
 CallFunction = PBFUNCTION(NumIn, NumOut)
 If CallFunction = 1 Then
    MsgBox "NumIn = " & Str$(NumIn) & ", NumOut is now " & Trim$(Str$(NumOut)) & " (should be twice the value of NumIn)"
 Else
    MsgBox "Call failed"
 End If
End Sub

[This message has been edited by Wayne Diamond (edited September 16, 2001).]

[Wayne Diamond]

[b]// CALLDELPHI.DPR - Call the DLL from Borland Delphi[/b]
{$APPTYPE CONSOLE}
{$X+}
program CallCRC32;
uses
  SysUtils,
  Windows;
 
Type
  longptr = ^longint;
 
Var
  xRet: Integer;
  xNumIn, xNumOut: longptr;
  xResult: LongInt;
 
Function PBFUNCTION(  NumIn: longptr; NumOut: longptr): Integer;
  stdcall; external 'PBDLL.DLL';
 
begin
  xNumIn^ := 10;
  xRet := PBFUNCTION(xNumIn, xNumOut);
  xResult := xNumOut^;
  writeln('xResult = ', xResult, ' (should be 20)');
end.

------------------

[Wayne Diamond]

[b]// CALLC.C - Call the DLL from C[/b]
#include "windows.h"
#include "stdio.h"
 
typedef int __stdcall LPFNCALLDLL( long &NumberIn, long &NumberOut );
int main(int argc, char* argv[])
{
 HMODULE hLib;
 LPFNCALLDLL* lpCallDll;
 long NumberIn, NumberOut;
 hLib = LoadLibrary( "PBDLL.DLL" );
 if ( hLib == NULL )
 {
        printf("Could not load PBDLL.DLL");
        return FALSE;
 }
 lpCallDll = (LPFNCALLDLL*)GetProcAddress(hLib, "PBFUNCTION");
 if ( lpCallDll == NULL )
 {
        printf("Could not find function in PBDLL.DLL");
        FreeLibrary( hLib );
        return FALSE;
 }
 int Result;
 NumberIn = 10;
 NumberOut = 0;
 Result = lpCallDll( NumberIn, NumberOut );
 FreeLibrary(hLib);
 printf("NumberIn is %d, NumberOut is now %d (should be twice the value of NumberIn)", NumberIn, NumberOut);
 return TRUE;
}

------------------

[Sven Blumenstein]

[b]; callasm.asm - Call the DLL from ASM (MASM)[/b]
        .386
        .model flat, stdcall
        option casemap :none
 
        include \masm32\include\windows.inc
        include \masm32\include\user32.inc
        include \masm32\include\kernel32.inc
 
        includelib \masm32\lib\user32.lib
        includelib \masm32\lib\kernel32.lib
  
    .data
        szMsg           db "NumIn = %lu, NumOut is now %lu (should be twice the value of NumIn)", 0
        szCap           db "Call PBDLL from ASM", 0
        szLib           db "pbdll.dll", 0
        szProc          db "PBFUNCTION", 0
 
    .data?
        NumIn           dd ?
        NumOut          dd ?
        szBuffer        db 512 dup(?)
 
    .code
 
callasm:
    mov NumIn, 10
    push offset szLib
    call LoadLibrary
    invoke LoadLibrary, addr szLib
    push eax
    invoke GetProcAddress, eax, addr szProc
    push offset NumOut
    push offset NumIn
    call eax
    call FreeLibrary
 
    invoke wsprintf, addr szBuffer, addr szMsg, NumIn, NumOut
    invoke MessageBox, 0, addr szBuffer, addr szCap, MB_OK
 
    invoke ExitProcess, eax
 

end callasm

------------------
Sven Blumenstein
IT-Trainee at DECOMA Exterior Systems, Germany
E-Mail (work): mailto:[email protected][email protected]</A>
E-Mail (home): mailto:[email protected][email protected]</A>
Programming with: PB/Dll, MASM, VB, VC++, LCC, VBA, WML

[This message has been edited by Sven Blumenstein (edited September 18, 2001).]