topic Re: Internal read in DLL in Intel® Fortran Compiler

Internal read in DLL

Robert_S_6 — Sat, 24 Jan 2004 02:36:27 GMT

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?

Re: Internal read in DLL

Steven_L_Intel1 — Sat, 24 Jan 2004 03:24:30 GMT

What Fortran compiler and version of same are you using?

Re: Internal read in DLL

Robert_S_6 — Sat, 24 Jan 2004 03:36:04 GMT

IVF 8.0

Re: Internal read in DLL

Steven_L_Intel1 — Sat, 24 Jan 2004 04:12:15 GMT

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.

Re: Internal read in DLL

Robert_S_6 — Sat, 24 Jan 2004 04:24:42 GMT

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.

Re: Internal read in DLL

Steven_L_Intel1 — Sat, 24 Jan 2004 04:44:20 GMT

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.

Re: Internal read in DLL

Robert_S_6 — Sat, 24 Jan 2004 05:00:19 GMT

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).

Re: Internal read in DLL

Robert_S_6 — Sat, 24 Jan 2004 09:42:02 GMT

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

Re: Internal read in DLL

Jugoslav_Dujic — Sat, 24 Jan 2004 18:04:48 GMT

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

Re: Internal read in DLL

Steven_L_Intel1 — Sat, 24 Jan 2004 23:11:46 GMT

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.

Re: Internal read in DLL

Robert_S_6 — Mon, 26 Jan 2004 21:45:05 GMT

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

Re: Internal read in DLL

Jugoslav_Dujic — Mon, 26 Jan 2004 22:05:54 GMT

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

Re: Internal read in DLL

Robert_S_6 — Mon, 26 Jan 2004 22:13:27 GMT

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

Re: Internal read in DLL

Robert_S_6 — Tue, 27 Jan 2004 01:46:38 GMT

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.

Re: Internal read in DLL

Jugoslav_Dujic — Tue, 27 Jan 2004 17:02:54 GMT

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

Jugoslav

Re: Internal read in DLL

Robert_S_6 — Wed, 28 Jan 2004 00:06:59 GMT

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

Bob

Re: Internal read in DLL

Steven_L_Intel1 — Wed, 28 Jan 2004 01:56:53 GMT

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.

Re: Internal read in DLL

g_f_thomas — Wed, 28 Jan 2004 07:51:59 GMT

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.

Re: Internal read in DLL

g_f_thomas — Wed, 28 Jan 2004 11:31:10 GMT

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.