Oh hb_font_t, I am sorry, as far as I know they are always valid, I don't know of a case that it can be invalid other than having an invalid hb_face_t. Maybe others can help better on this. Relying on hb_shape_full result is not that common practice as most of clients don't use it and they use hb_shape which returns void, I suggest you to stick to that also. On Wednesday, May 29, 2019, Ebrahim Byagowi <<a href="mailto:ebraminio@gmail.com" target="_blank">ebraminio@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Getting glyph count is just as good anything you can thing, if a font doesn't have a glyph it is either empty or corrupted, there no valid use case for such AFAICU On Wednesday, May 29, 2019, Eli Zaretskii <<a href="mailto:eliz@gnu.org" target="_blank">eliz@gnu.org</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Last time I asked a similar question, I was told to use hb_face_get_glyph_count. But eventually I need to know that an hb_font_t I create from the face is valid and can be used for shaping. What are the best practices for doing that? Or maybe the shaper will return 'false' when given an invalid font, and all I need is to test the return value of the shaper? TIA _______________________________________________ HarfBuzz mailing list <a href="mailto:HarfBuzz@lists.freedesktop.org" target="_blank">HarfBuzz@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/harfbuzz" target="_blank">https://lists.freedesktop.org/mailman/listinfo/harfbuzz</a></blockquote> </blockquote>