[Ecls-list] how to convert a string from lisp to a c string (char *)?

[yami]

Hi,

How can I convert a string from lisp to a c string, so that I can use it in
C?
It seems a FAQ question, but I can not find the answer...

My current version looks exactly like:

-------------------C---------------------
int main(int argc, char** argv)
{
    cl_boot(argc, argv);
    cl_load(1, make_base_string_copy("simple.lisp"));

    for (int i=0; i<220; i++) {              /* 220 is just a random large
value for testing, see below */
        cl_object cl_string = cl_funcall(1, cl_intern(1,
make_simple_base_string("GET-STRING")));
        char*      c_string = ecl_base_string_pointer_safe(cl_string);
    }

    cl_shutdown();
}

--------------------CL: simple.lisp---------------------------
(defun get-string ()
  (let ((result (format nil "<?xml version='1.0' encoding='UTF-8'
standalone='no'?>~%~%<svg xmlns='http://www.w3.org/2000/svg'
version='1.1'>~%  <rect x='0' y='0' width='fixed' height='fixed'
style='fill: none' stroke='blue' />~%</svg>~%")))
    (print (format nil "$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$~%"))
    (print (format nil "~a~%" result))
    (print (format nil "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx~%"))
    result))

However when I ran the program, after several correct iterations, I
encountered following problem:

--------------------OUTPUT------------------------------
Cannot coerce a string with fill pointer to (char *)

Available restarts:

1. (QUIT-DEBUGGER) Quit debugger level 1.

Broken at NIL.

So I mean the error occurs after several successful iterations.

Any ideas?
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