+(defmacro with-growing-c-string ((buffer size) &body body)
+ (sb-int:with-unique-names (c-string-block)
+ `(block ,c-string-block
+ (let (,buffer)
+ (flet ((,buffer (&optional (size-incl-null))
+ (when size-incl-null
+ (setf (sb-sys:sap-ref-8 (sb-alien:alien-sap ,buffer) size-incl-null)
+ 0))
+ (return-from ,c-string-block
+ (sb-alien::c-string-to-string
+ (sb-alien:alien-sap ,buffer)
+ (sb-impl::default-external-format)
+ 'character))))
+ (loop for ,size = 128 then (* 2 ,size)
+ do (unwind-protect
+ (progn
+ (setf ,buffer (make-alien c-string ,size))
+ ,@body)
+ (when ,buffer
+ (free-alien ,buffer)))))))))
+