Comment 29 for bug 327757

I'm pretty sure the bug is in fontconfig and not in poppler. It looked to me like more recent versions of poppler did not exhibit the bug because they call fontconfig differently. However, the underlying bug remains in the fontconfig library and will affect other people who try to use the library.

There's a fair amount of information in the Ubuntu bug report:
https://bugs.launchpad.net/ubuntu/+source/evince/+bug/327757

Specifically, please see this code sample:
http://launchpadlibrarian.net/22890843/fchello.c

It demonstrates that FcFontSort is apparently not sorting correctly and, actually, gives a different result from what fc-match gives.