[cairo] CAIROMM: Status type and Xlib

Jonathon Jongsma jonathon.jongsma at gmail.com
Sat Jan 14 21:49:46 PST 2006

On 1/14/06, Jim Gettys <jg at freedesktop.org> wrote:
> On Thu, 2006-01-12 at 08:41 -0600, Jonathon Jongsma wrote:
> > In experimenting with implementing a heirarchy of surfaces in cairomm,
> > I've run across a problem that took me a while to track down.  cairomm
> > typedefs cairo_status_t as Cairo::Status.  This was working fine until
> > I added support for XlibSurface, which needs to pull in a bunch of
> > xlib headers.  The problem is that Xlib.h contains the line:
> >
> > #define Status int
> >
> > So any Status type that occurs after Xlib.h is included gets replaced
> > by the preprocessor with 'int'.  I don't know why it's a #define
> > instead of a typedef.
> Hysterical reasons: typedef wasn't available universally at the time
> that line was written, IIRC.
> #undef is your friend.
>                         - Jim

I'm using #undef currently to work around this in my development code,
but I figure that if somebody is using the XlibSurface in cairo, they
will need to write code that uses XLib, so #undef-ing a type would
theoretically cause problems in any code that they wrote which
attempted to use XLib's Status type, no?

Murray, was your plan to remove the Status type from API completely
and only use exceptions when an error occurred?  (Currently the Status
type is exposed as a return type for the functions
Surface::write_to_png() and Surface::write_to_png_stream() but I
believe those were implemented by me and maybe should be changed?)  I
recall some debate in the past about making the use of exceptions
optional, but don't remember what the outcome of that discussion was. 
If it isn't exposed in the API, I guess changing the name of the type
in cairmm isn't as big of a deal -- any thoughts?


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