Internal read in DLL

[Robert_S_6]

I am creating a Fortran DLL to be used by Access. I have gotten the dll to work with access without a problem. Now, I am trying to read from a string inside the dll and the program causes access to shut down. Here is the code for a test subroutine that i have been working with.

SUBROUTINE

TESTDATA () !dec$ attributes alias : "TESTDATA" :: TESTDATA !dec$ attributes dllexport :: TESTDATA !dec$ attributes stdcall :: TESTDATA CHARACTER TESTSTRING*2000 CHARACTER TESTRWYKEY*15,TESTICAO*4,TESTIATA*3

TESTSTRING = "KPIT10R KPITPIT"

READ(UNIT=TESTSTRING,FMT=4000)TESTRWYKEY,TESTICAO,TESTIATA 4000 FORMAT(A15,A4,A3)

END SUBROUTINE

TESTDATA

When I use this same code in an executable, it works without a problem. Also, if i write the data to a file, and then read the file, there is not a problem. Has anyone encountered this before?

[Steven_L_Intel1]

What Fortran compiler and version of same are you using?

[Robert_S_6]

IVF 8.0

[Steven_L_Intel1]

I can't think of a reason why this should be. Is the routine you posted exactly the one you're using? I ask because it has no outputs, so it seems unlikely that you'd call it from Access.

[Robert_S_6]

The code that I posted is just test code, i started with passing string arrays back and forth from access, but then when my problem started, i tried to isolate the problem. that's when i created the sample dll that i posted. i have been using write statements to write to a text file and the text file is blank when the program finishes. I also use statements such as "program is here" when writing to the text file to further isolate the problem.

[Steven_L_Intel1]

Are you sure that the access violation happens in the routine, or is it perhaps after it returns to Access? You can debug a DLL - see here for instructions.

[Robert_S_6]

I am sure that it is in the dll. When I remove the read statement, or read from a text file, the dll works fine. The program is compiled in Visual Studio.net. I don't know if that makes a difference or not. I have tried to use the debugger, but when i use msaccess.exe, i get a message that says, msaccess.exe does not contain debugging information (no symbols loaded).

[Robert_S_6]

i found that the debugging issue is a confirmed bug in vs.net from the microsfot kb

[Jugoslav_Dujic]

Hmmm... as I understand it, "xxx.exe does not contain debugging information" message is not a limiting factor -- anyway, you don't want to debug msaccess.exe but your dll, which you should be able to debug. So, you can ignore the message, place a breakpoint into your code, and perform actions in Access to trigger your routine -- the debugger will stop at the breakpoint.

Jugoslav

[Steven_L_Intel1]

I agree with Jugoslav. After setting the executable file name to that of Access, just set a breakpoint in your DLL routine and click GO. Access will start, and the debugger will gain control when your routine is called.

[Robert_S_6]

Thanks for the help so far. I have the debugger working and this is what happened.

Unhandled exception at 0x098ab8b5 in MSACCESS.EXE: 0xC0000005: Access violation reading location 0x00000000.

Any clues?

Bob

[Jugoslav_Dujic]

Well... not really. When does the AV occur? Before, during,or after your breakpoint is hit? How does the calling code in MSAccess look?

Jugoslav

[Robert_S_6]

I use a simple form and button to call the dll

Private Declare Sub TESTDATA Lib "C:TEMPDll1.DLL" ()

Private Sub Command0_Click()
On Error GoTo Err_Command0_Click

Call TESTDATA

MsgBox "PROGRAM DONE"

Exit_Command0_Click:
Exit Sub

Err_Command0_Click:
MsgBox Err.Description
Resume Exit_Command0_Click

End Sub

The error seems to occur when the breakpoint is hit.

Bob

[Robert_S_6]

I set my breakpoint on the following line

TESTSTRING = "KPIT10R KPITPIT"

and the when i continue to the next line is where the error occurs.

[Jugoslav_Dujic]

Does it still crash if you add IOSTAT=iErr argument into READ statement? If not, what's the value of iErr?

Jugoslav

[Robert_S_6]

I placed the IOSTAT line in my code, and the program still crashed at the read statement.

Bob

[Steven_L_Intel1]

At this point I suggest you submit the problem to Intel Premier Support - be sure to attach the necessary sources (including Access form and instructions for using) to reproduce the problem.

[g_f_thomas]

Pardon the interjection but in the posted Fortran

CHARACTER TESTSTRING*2000

CHARACTER TESTRWYKEY*15,TESTICAO*4,TESTIATA*3

TESTSTRING = "KPIT10R KPITPIT"

READ(UNIT=TESTSTRING,FMT=4000)TESTRWYKEY,TESTICAO,TESTIATA 4000 FORMAT(A15,A4,A3)

can UNIT in a READ be a character string? I've long believed that it had to be an integer, eg, 5.

Maybe the storm has gottento me, :-).

Ciao

Gerry T.

[g_f_thomas]

Duh, too much snow on the brain!

Missed the operative 'internal' read part. So the sole record of the file is of length 2000 or is it?.

Ciao,

Gerry T.