pango:fontset-foreach (fontset func)

fontset -- a pango:fontset object
func -- a pango:fontset-foreach-func callback function

Iterates through all the fonts in a fontset, calling func for each one. If func returns true, that stops the iteration. Code fragment for counting the fonts in a fontset and for printing a list of the font descriptions.

(let ((count 0))
  (pango:fontset-foreach fontset
          (lambda (fontset font)
            (declare (ignore fontset))
            (let* ((desc (pango:font-describe font))
                   (str (pango:font-description-to-string desc)))
              (format t "~a : ~a~%" count str)
              (incf count)
              nil)))
  count)