On Mon, Sep 1, 2008 at 3:47 PM, Andy Chambers
<[EMAIL PROTECTED]> wrote:
> int sqlite3_open(
> const char *filename, /* Database filename (UTF-8) */
> sqlite3 **ppDb /* OUT: SQLite db handle */
> );
Let's start by declaring this function:
(defcfun ("sqlite3_open" %sqlite3-open) :int
(filename :string)
(db :pointer))
> I'd like to define a cffi function that lets me call this and keep a
> handle on the ppDb object that gets
> created as a result.
(defun sqlite3-open (filename)
"Open FILENAME and return a handle to the DB."
(with-foreign-object (db :pointer)
(%sqlite-open filename db) ; XXX: do error checking here...
(mem-ref db :pointer)))
That WITH-FOREIGN-OBJECT form allocates enough memory to hold a
pointer. And the value of DB is a pointer to that newly allocated
memory. We pass that to sqlite3_open() which will fill that memory
with the DB handle (which is a pointer, i.e., an address that points
to some opaque SQLite structure).
Finally, through MEM-REF, we access our newly allocated memory and get
the DB handle.
HTH
--
Luís Oliveira
http://student.dei.uc.pt/~lmoliv/
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