Looking at code examples under cairo_scaled_font_text_to_glyphs there is imporper usage of several cairo functions:
cairo_glyph_t *glyphs = NULL;
cairo_show_glyphs (..., *glyphs, ...);
this is wrong, as cairo_glyph_free expects a single pointer
The same inconsistency can be seen in the usage of:
Thank you for the bug report.
Author: Chris Wilson <email@example.com>
Date: Mon Oct 26 11:05:38 2009 +0000
scaled-font: Fix documentation examples with incorrect derefs
Bug 24730 -- New: misleading use cases in cairo_scaled_font_text_to_glyphs's docs
An apparent copy'n'paste error from the code which has to deal with
indirect pointers crept into the documentation for the same functions.