[GRASSLIST:772] Re: FIX: gdal/v.in.dgn support with grass 5.0.2

[Frank Warmerdam]

Paul Kelly wrote:
>>I agree, the main problem is that, at least, we must verify that the library
>>we are just about to link against matches the API use by the code, i.e. that
>>the prototypes are correct but this can only be achieved if this the gdal
>>package which installs the headers needed (it should be so since gdal installs
>>also statically linked library which are typically used when compiling...).
> 
> 
> Well we can only ask the GDAL developers what the situation is or how it's
> supposed to be done [message copied to that list]...

Paul, and others,

It isn't generally my intention that GDAL should by default install the
include files for component libraries like dgnlib when it is being installed.
I feel that as the number of drivers grows this will introduce alot of clutter.
Also, I don't necessarily guarantee that all the sublibrary entry points will
be exposed externally from the main gdal library on platforms like Windows
where this must be explictly done.

I would be willing to add a "devinstall" target in the gdal/ogr/ogrsf_frmts/dgn
directory that installs all the dgnlib specific include files if you wish,
and also make some effort to ensure that the dgnlib API is properly exported
from the GDAL library on windows.  However, this would still mean that
users installing dgnlib would need to do an extra step for use by GRASS,
I would imagine this would be frequently forgotten leading to lots of
additional problems.  Of course, those preparing distributions could
presumably deal with this.

A similar issue came up a while ago with shapelib, and I somewhat reluctantly
agreed to install the shapelib include files, and ensure that the entry
points are exported from GDAL DLLs.  (I think I did anyways)  However, I
am not keen on following that example for all sorts of other libraries.

My *suggestion* would be to make v.in.dgn optional, dependent on whether
the appropriate components are installed, and to try to deal with DGN
primariliy via the OGR link in the new GRASS.

Let me know if you want me to add the dgnlib devinstall target in time
for GDAL 1.2.0.

Best regards,

-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent