[Rd] R console freezes after several runs of compiled C code

[Simon Urbanek]

On Apr 14, 2009, at 4:57 PM, Xiangyang Ye wrote:

> Hi All,
>
> I tried my best to figure out how to deal with the freezing R  
> console but
> with no luck. I followed the instructions of calling R_ProcessEvents()
> regularly but still couldn't work it out (the callings were removed  
> from the
> below C code).
>

It's not a hang - it's a crash because of a bug in your code. Look at  
the last loop - I suspect you meant j<*n and not j<*m otherwise you'll  
be corrupting memory.

FWIW if you want to make a GUI responsive, you should be calling  
R_CheckUserInterrupt() and not R_ProcessEveents() because the latter  
is not available on all platforms.

Cheers,
Simon


> I am using R-2.8.1 on Windows XP service pack 3. The Rtools is  
> version 2.9.
> I have the following C code:
>
> void rx(int *n, int *m, int *rxmax,int *rxdate, int *refills,int  
> *rxs) {
>  int i,j,k, total;
>  int cap[*n][*m];
>  int rx[*n* *rxmax][*n];
>
>  for (i=0;i<*n;i++)
>    for (j=0;j<*m;j++)
>   cap[i][j]=0;
>
>  for (i=0;i<*n* *rxmax;i++) {
>  rx[i][0]=*(rxdate+i);
>     rx[i][1]=*(refills+i);
>     }
>
>  for (i=0;i<*n;i=i+1)
>   for (j=*rxmax *i;j<(i+1) * *rxmax-1;j++)
>        if (rx[j][0] > 0)
>          for (k = rx[j][0]; k < rx[j][0] + rx[j][1]; k++){
>          if (k<*m)
>            cap[i][k]=1; }
>
>  for (j=0;j<*m;j++)
>    for (i=0,total=0;i<*m;i++) {
>      total= total+cap[j][i];
>      rxs[j]=total;
>      }
> }
>
> And the following R code:
>
> dyn.load("c:/temp/rxc.dll")
> rx=matrix(c(1,5,11,5,21,5,0,0,
>            1,10,21,10,0,0,0,0),nrow=8, byrow=T);
> n=2
> m=31
> x=c(1:n)
> rxmax= dim(rx)[[1]]/n
> xx <- .C("rx",n=as.integer(n),m=as.integer(m),rxmax=as.integer(rxmax),
>      rxdate = as.integer(rx[,1]),
>      refills = as.integer(rx[,2]),rxs=as.integer(x))
> xx$rxs
>
>
> After I created the .dll file, I was able to load it into R and got  
> the
> result that I expected. But if I re-run the code for several times,  
> the R
> console will freeze.
>
> Thanks in advance.
>
> Xiangyang
>
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>
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