Re: hypenator.cc errors

On Fri, Sep 06, 2013 at 11:46:10AM +0200, Sebastian Geerken wrote:
> > > [...]
> > 
> > Thinking about it again, variable length arrays are a feature of C,
> > but not of C++, although it seems that most C++ compilers support it.
> > Since this is a nice feature, but standard C++ should be supported,
> > I've thought of testing it by the configure script, and then hide two
> > different implementations behind a macro. See attached patch, which
> > should be applied to the current hg repository.
> > 
> > What do you think? [...]
> 
> Third round: I agree with Jorge that this is quite too complex; and
> profiling shows no performance gain of using the heap over using the
> stack, so I've replaced it by new and delete. Cris: please test the
> latest version from hg, it should compile now.

  There's a memory problem with the sizeof(buf) because it returns
the pointer size, not the array length!

  Please see the attached test case for details.

  (Compile with: g++ -W -Wall size3.cc -o size3)


-- 
  Cheers
  Jorge.-

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#include <stdio.h>
#include <string.h>

int main(void)
{
   const char *patFile="/home/somewhere";
   char *buf1 = new char[strlen (patFile) + 5 + 1];

   /* Bug */
   printf("strlen (patFile): %lu\n", strlen(patFile));
   printf("strlen (buf1): %lu\n", strlen(buf1));
   printf("sizeof (buf1): %lu\n", sizeof(buf1));
   printf("sizeof (*buf1): %lu\n", sizeof(*buf1));
   snprintf(buf1, sizeof (buf1), "%s.trie", patFile);
   printf("buf1: %s\n\n", buf1);


   /* OK */
   size_t buf2len = strlen (patFile) + 5 + 1;
   char *buf2 = new char[buf2len];
   printf("strlen (patFile): %lu\n", strlen(patFile));
   printf("strlen (buf2): %lu\n", strlen(buf2));
   printf("sizeof (buf2): %lu\n", sizeof(buf2));
   printf("sizeof (*buf2): %lu\n", sizeof(*buf2));
   snprintf(buf2, buf2len, "%s.trie", patFile);
   printf("buf2: %s\n", buf2);


   delete[] buf2;
   delete[] buf1;
   return 0;
}