R help - Feb 2004 - RGui (Windows) crashes after use of a Salford Fortran DLL

Anybody out there successfully using the Salford Fortran compilers 
with R? 

I have created a DLL using the Salford FTN95 compiler and it works 
in as far I can dyn.load it, run the routines and get the  right 
answers back. Unfortunately subsequently, sometime later, the 
Rgui crashes (access violation I think from the DrWatson log). The 
crashes depend on whether or not I paste the code as one big 
chunk, or as little chunks, and sometimes I can do a few things 
before it crashes and other times not - but if I do exactly the same 
things the crashes are reproducible. The crashes are sometimes in 
the DLL and sometimes in pure R code. R1.7.1 and 1.8.1 seem to 
behave identically. Windows 2000 Pro.

I do get the dyn.load warning about the DLL changing the FPU 
control word.

Does this ring any bells with anyone?

Steve.

  Dr Steve Roberts 
  steve.roberts at man.ac.uk

Senior Lecturer in Medical Statistics,
CMMCH NHS Trust and University of Manchester Biostatistics Group,
0161 275 5192 / 0161 276 5785

My suggestion would be to make sure that your code works with the
recommended compilers, and that the problem is not in your code.  (This is
harder than you might think:  I recently found a bug in a Fortran subroutine
that crashes R _only_ if I use the latest GCC _and_ turn on optimization.)

Andy
> From: Steve Roberts
> 
> Anybody out there successfully using the Salford Fortran compilers 
> with R? 
> 
> I have created a DLL using the Salford FTN95 compiler and it works 
> in as far I can dyn.load it, run the routines and get the  right 
> answers back. Unfortunately subsequently, sometime later, the 
> Rgui crashes (access violation I think from the DrWatson log). The 
> crashes depend on whether or not I paste the code as one big 
> chunk, or as little chunks, and sometimes I can do a few things 
> before it crashes and other times not - but if I do exactly the same 
> things the crashes are reproducible. The crashes are sometimes in 
> the DLL and sometimes in pure R code. R1.7.1 and 1.8.1 seem to 
> behave identically. Windows 2000 Pro.
> 
> I do get the dyn.load warning about the DLL changing the FPU 
> control word.
> 
> Does this ring any bells with anyone?
> 
> Steve.
> 
>   Dr Steve Roberts 
>   steve.roberts at man.ac.uk
> 
> Senior Lecturer in Medical Statistics,
> CMMCH NHS Trust and University of Manchester Biostatistics Group,
> 0161 275 5192 / 0161 276 5785
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 
> 

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Steve Roberts wrote:
> Anybody out there successfully using the Salford Fortran compilers 
> with R? 
> 
> I have created a DLL using the Salford FTN95 compiler and it works 
> in as far I can dyn.load it, run the routines and get the  right 
> answers back. Unfortunately subsequently, sometime later, the 
> Rgui crashes (access violation I think from the DrWatson log). The 
> crashes depend on whether or not I paste the code as one big 
> chunk, or as little chunks, and sometimes I can do a few things 
> before it crashes and other times not - but if I do exactly the same 
> things the crashes are reproducible. The crashes are sometimes in 
> the DLL and sometimes in pure R code. R1.7.1 and 1.8.1 seem to 
> behave identically. Windows 2000 Pro.
> 
> I do get the dyn.load warning about the DLL changing the FPU 
> control word.
> 
> Does this ring any bells with anyone?
Duncan Murdoch has collected some notes on different compiler issues on 
Windows (don't know whether Salford FTN95 is among them). Nevertheless, 
it is recommended to use the MinGW port of the gcc compiler with R.

Uwe Ligges


> Steve.
> 
>   Dr Steve Roberts 
>   steve.roberts at man.ac.uk
> 
> Senior Lecturer in Medical Statistics,
> CMMCH NHS Trust and University of Manchester Biostatistics Group,
> 0161 275 5192 / 0161 276 5785
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html

On Wed, 11 Feb 2004 11:30:35 +0000, "Steve Roberts"
<steve.roberts at man.ac.uk> wrote :
>Anybody out there successfully using the Salford Fortran compilers 
>with R? 
>
>I have created a DLL using the Salford FTN95 compiler and it works 
>in as far I can dyn.load it, run the routines and get the  right 
>answers back. Unfortunately subsequently, sometime later, the 
>Rgui crashes (access violation I think from the DrWatson log). The 
>crashes depend on whether or not I paste the code as one big 
>chunk, or as little chunks, and sometimes I can do a few things 
>before it crashes and other times not - but if I do exactly the same 
>things the crashes are reproducible. The crashes are sometimes in 
>the DLL and sometimes in pure R code. R1.7.1 and 1.8.1 seem to 
>behave identically. Windows 2000 Pro.
>
>I do get the dyn.load warning about the DLL changing the FPU 
>control word.
>
>Does this ring any bells with anyone?
A reproducible crash sometime later sounds to me like memory
corruption.  I'd guess the crash occurs at the next garbage
collection; something has happened to mess up the internal memory
structures, so R goes down.

You can call gc() to trigger a garbage collection just after your call
to your DLL; that's likely to trigger the crash if my guess is right.
Fixing it will be harder:  you need to find why your DLL is writing in
someone else's memory space.  Perhaps make your arrays larger than
necessary, and check that values that weren't supposed to be touched
stay untouched?

Regarding the FPU control word:  general instructions to fix this bug
in your DLL are given on my web page
<http://www.stats.uwo.ca/faculty/murdoch/software/compilingDLLs/>. If
there's anything special about the Salford compiler that needs
mentioning there, please write it up and send it to me.

Duncan Murdoch