[XeTeX] long search time when font doesn't exist

[Will Robertson]

On Wed, Apr 23, 2008 at 11:27 PM, Ulrike Fischer <news2 at nililand.de> wrote:
>  if I try to use a font that doesn't exist (e.g. because I mistype the
>  name) then xelatex stops for about a minute while the hard drive is
>  quite busy. Then I get the expected "tfm missing" error.

This happens on other platforms too. As I understand, XeTeX has a
cache of fontnames that it uses to speed up font access, but the first
time a font is used, it will be quite slow; when a font cannot be
found, it goes to some effort to locate a copy on disk, but is
obviously unsuccessful.

I could possibly see the utility of a flag to turn this off, but it
doesn't generally bother me too much :)

Incidentally, this slowdown is the primary reason that an
\IfFontExists macro isn't really feasible.

Will