Library for .3d files

[Olly Betts]

No need to email both the list and me directly.  I'm definitely
subscribed to the list.

On Thu, Feb 27, 2025 at 09:24:40AM -0800, Philip Schuchardt wrote:
> It seem like there's 4 files that make up the .3d library:
> 
> img.h
> img.c
> img_hosted.h
> img_hosted.c
> 
> Since img_hosted.c just includes img.c, I can probably make a static
> library from that.

You just want img.c and img.h - the other two are only useful if you're
building Survex.  They mostly just hook message translation for img
errors into Survex's translation machinery, which is not useful outside
of Survex (they used to do more but I've slowly been eliminating that;
at some point they may go away entirely).

The expected way to use img is that you copy these two files into your
source tree, and periodically update them (evolution is usually glacial).
It's not packaged as a separate library for Debian or anywhere else I'm
aware of (there's a very low number of applications which link to it and
the effort to do that seems more usefully directed; we also don't
guarantee ABI stability, but it should be upwardly API compatible).

See imgtest.c for an example program using img in "unhosted mode" (which
is how you'd use it outside of Survex).  Also dump3d.c shows how to
access all the different types of data returned (that's built "hosted"
but only affects the includes, linking and error reporting).

Cheers,
    Olly