Well, you can use Inline::C, like so (the library already has a type def for char * so you don't even have to mess with an SV):

use Inline C => << 'END_OF_C_CODE';

char * return_string (int pnt)
{
  char *str = pnt;
  return str;
}

END_OF_C_CODE

my $string = return_string($pnt);
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Update: So now you think it is a point to a scalar? That would be very strange. If the C function wrapped in XS has a return type of SV* (a pointer to a scalar), XS will coerce it to a scalar in perl. Actually, the same is true for char *. The only way to return an actual address to you for a basic type (types XS already has conversions for) is through an int. I'm wondering why anyone would ever want to do this, since perl programmers have little use for addresses.