Patrick Lam <plam@xxxxxxx> さんは書きました: > Ideally we wouldn't change the cache format once fontconfig becomes > stable. But I guess that's not a very satisfactory answer, because we > might have to change the cache format more than we might like. One > option is to increment the cache version number (fonts.cache-3, etc). > >> fcint.h contains a magic number >> >> #define FC_CACHE_MAGIC 0xFC02FC02 >> >> which appears to be intended for that purpose. > > The magic number just helps determine that it's a fontconfig cache, but > I suppose it could be changed. The other thing is that there's a line > for determining architectures (by recording sizeof various things); this > line could also have a version number incorporated into it. > > The question, I guess, is how often we're going to have these > incompatible changes. If it's not very often, then we increment the > filename number. If it's going to be more often than that, we can > change the magic number. I'm not really sure which is best. Dirk Müller <dmueller@xxxxxxx> told me that incrementing the magic number might cause a problem if some 3rd party software vendors distribute applications which are statically linked against older versions of fontconfig. When calling such statically linked applications and "normal" applications alternately, the cache files will always be updated because the magic number is always wrong. Dirk had the idea that this could be avoided by having a version number in the architecture signature. You also wrote above that this is a possibility. Having the version number in the architecture signature might avoid the problem with applications statically linked against fontconfig because those would get their own architecture section. I don't know whether applications linked statically against fontconfig exist, i.e. I don't know whether this problem is important in practice or not. -- Mike FABIAN <mfabian@xxxxxxx> http://www.suse.de/~mfabian 睡眠不足はいい仕事の敵だ。 _______________________________________________ Fontconfig mailing list Fontconfig@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/fontconfig
