Passing string arrays to DLL (32 bit) 
Author Message
 Passing string arrays to DLL (32 bit)

We are trying to write an application in VB 4.0 (32 Bit) that can pass
an array of structures containing a string to a MSVC++ 4.0 DLL. When we
look at the result only the string in the 1st structure of the array
shows up. The rest looks like uninitialized memory. The DLL works if we
use a C program to pass the array of structures. Could it be that we
are using a String instead of Byte in VB?

Has anybody tried something similar & been sucessful. Any help would
be GREATLY appreciated

                        thanx in advance


'************************  VB Program *******************************

'String arrays should be passed as structure arrays to C
Type StructElem
    'strings passed to c should be fixed length
    StructOccur As String * 40
End Type

' Declare function in Dll
Declare Sub CStrArrayCat Lib

Private Sub cmdStrArrayCat_Click()

    Static structArray(4) As StructElem  ' create array of structures

    structArray(0).StructOccur = "abnc"         ' Init array
    structArray(1).StructOccur = "Testing"
    structArray(2).StructOccur = "today"

   'call c routine in DLL
    CStrArrayCat structArray(0)

End Sub

******************   C  DLL Program **************************

// C structure
typedef struct
        char szStructOccur[40];

} StringStructType;

// DLL function being passed the array of structures
__declspec( dllexport ) void CStrArrayCat(StringStructType

Sat, 25 Jul 1998 03:00:00 GMT  
 [ 1 post ] 

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