[R] Passing character strings from C code to R

Tuszynski, Jaroslaw W.
Fri, 15 Jul 2005 12:57:30 -0000

Hi,

I have a C code which produces array of integers and potentially a string,
and I have problems passing the string out. Here is the relevant part of the
code:

 1   PROTECT(Ret = allocVector(INTSXP, n));
 2   ret     = (int*) INTEGER(Ret);  /* get pointer to R's Ret */
 3   for(i=0; i<n; i++) ret[i] = data[i];
 4   Free(data);
 5   i=1;
 6   if (comment) { // comment was found
 7     n = strlen(comment);
 8     if(n>0) {    // and it actually have some length
 9        Rprintf(" '%s' %i\n", comment, n);
 10       PROTECT(Str = allocString(n+1));
 11       str = CHAR(STRING_ELT(Str, 0));
 12       strcpy(str, comment);
 13       Rprintf(" '%s' %i\n", str, n);
 14       setAttrib(Ret, install("comm"), Str);
 15       i=2;
 16     }
 17     Free(comment);
 18   }
 20   UNPROTECT(i);

Print statement in line 9 gives right results, but program crashes before
print statement in line 13.
Any ideas to what am I doing wrong?

Jarek
=====================================\====
 Jarek Tuszynski, PhD.                               o / \
 Science Applications International Corporation  <\__,|
 (703) 676-4192                        ">  \
 Jaroslaw.W.Tuszynski at saic.com                   `    \