[GRASS5] PNG (was releases - some remarks)

[Markus Neteler]

On Thu, Mar 18, 2004 at 05:14:13AM +0000, Glynn Clements wrote:
> 
> Richard Greenwood wrote:
> 
> > > FWIW, the 5.3 PNG driver should work fine with 5.0.3; i.e. you should
> > > be able to drop the 5.3 driver/PNG.exe into a 5.0.3 installation
> > > without any complications.
> > > 
> > > Is the 5.0.3 PNG driver built with GD 2.x? If not, it might be worth
> > > making the 5.3 version available separately for any 5.0.3 users who
> > > want to create 24-bit PNGs (GD 1.x only supports 8-bit PNGs).
> > 
> > Yes, my 5.0.3 is compiled with GD 2.x. However I have a new PNG related 
> > problem - when building 5.7 it fails in display/drivers/PNG. The full 
> > output is pasted below. There are various references to xdr_ types and 
> > functions. I have a current sun rpc installed.
> > 
> > Suggestion?
> 
> > /cygdrive/e/projects/grass/grass57_exp_2004_03_13/dist.i686-pc-cygwin/lib/libgra
> > ss_gis.a(opencell.o)(.text+0x780):opencell.c: undefined reference to 
> > `xdrmem_create'
> 
> Short version:
> 
> Add $(XDRLIB) anywhere after $(LIBES) in the actual link command (the
> last non-empty line in display/drivers/PNG/Makefile).

Fixed in CVS.

> Long version:
> 
> This is due to an error in the 5.7 Makefile; libgis uses XDR functions
> for storing FP values, so anything which uses libgis also requires the
> library which provides the XDR functions (the $(XDRLIB) variable
> exists for this purpose).
> 
> On Linux, the XDR functions are in GNU libc, which is linked
> automatically, so forgetting to add $(XDRLIB) to the link command
> won't actually cause any problems.
> 
> On Cygwin, the XDR functions are in a separate library (librpclib.a)
> so, if the Makefile omits $(XDRLIB), the link will fail.
> 
> So, add $(XDRLIB) anywhere after $(LIBES) in the actual link command
> (the last non-empty line in display/drivers/PNG/Makefile).
> 
> Ultimately, include/Make/Grass.make.in should be re-written so that
> the definition of GISLIB includes $(XDRLIB); it already includes some
> of its dependencies, but not XDRLIB.
> 
> OTOH, this approach can result in the executables having unnecessary
> dependencies when the GRASS libraries are built as static libraries. 
> E.g. GISLIB has $(SOCKLIB) as a dependency, although that is only
> actually required for the functions in lib/gis/unix_socks.c. 
> Consequently, all programs which use libgis will have a dependency
> upon $(SOCKLIB), although most of them don't actually need it.
> 
> It's arguable that $(SOCKLIB) should be moved to the libraries which
> actually use the G_sock_* functions (i.e. libraster and libdriver).

Glynn,

may I ask you to implement the suggestions? I don't know enough about
good Makefile programming to do it. Before making it worse, I would
like to ask you to fix the problem.

Markus