Re: [Devel] Close on exec for font files

[Keith Packard]

Around 10 o'clock on Dec 26, Scott Long wrote:

> it is better to just use that API rather than introducing UNIX-specific
> code into a cross-platform library. If similar issues arise in Windows (I
> have no idea, don't program Windows) then this solves the problem on both
> platforms instead of just one.

If a similar issue arrises on another platform (it doesn't on Windows), 
then the library could solve it there as well.  Here's a diagram of the 
API heirarchy I'm dealing with:

        Application
            v
           KDE
            v
           Qt
            v
           Xft
            v
        FreeType

The application has no idea it's using FreeType, neither does KDE, nor Qt. 
At the application level, it doesn't even know what fonts are in use; the 
toolkit selects them based on the current UI theme in use.  So, I'd have 
to add a blanket "clean up all open fonts" call at the KDE level and the Qt 
level, and then special calls at the Xft level to pass through the 
FT_Done_FreeType call.

As Qt is also cross-platform, this call will not be needed *except* on 
Unix systems, where failing to call it may well cause problems.  Instead 
of forcing applications to make a call which is not always needed, it 
makes a lot more sense to have the library which knows that it is needed 
handle it transparently.

The only relevant question that I can see is whether there is a case where 
this call would be incorrect, and as the internal library state gets 
destroyed across the 'exec', I find it hard to believe such a case exists.

Keith Packard        XFree86 Core Team        Compaq Cambridge Research Lab