[GRASS-dev] grass7 problems with MASK

[Soeren Gebbert]

Hi,
i have had the same problem and implemented an identical solution.
But the problem was hard to figure out, because G_fatal_error() is now called
if opening or closing of maps fails.
The problem appeared when i started r.sim.water after creating a mask.
So i searched the error first in r.sim.water, because i changed the
memory allocation
recently and enabled the compilation of this module.

After a while i implemented an artificial segfault in G_fatal_error()
to enable debugging with gdb and valgrind and found the problem.

Therefor i would like to suggest to establish an environmental
variable to enable
G_fatal_error() to segfault for better error debugging. I was thinking
of a variable
in gisrc, but this will result in an infinite G_fatal_error()
call-loop, because G_fatal_error() is called in case the environmental
variable is not present in gisrc.

What would be the best way to implement such an behavior of G_fatal_error()?
Any suggestions are welcome.

Best
Soeren

2010/1/13 Markus Metz <markus.metz.giswork at googlemail.com>:
> Because of r40217, Rast_close() and Rast_unopen() can no longer be called
> unconditionally. That gives me errors when a MASK is present:
> ERROR: Invalid descriptor: 0
>
> The following patch to lib/raster works for me but I'm not sure if this is
> the right way
>
> Index: init.c
> ===================================================================
> --- init.c    (revision 40418)
> +++ init.c    (working copy)
> @@ -83,6 +83,7 @@
>
>    /* Set masking flag unknown */
>    R__.auto_mask = -1;
> +    R__.mask_fd = -1;
>
>    R__.nbytes = sizeof(CELL);
>    R__.compression_type = getenv("GRASS_INT_ZLIB") ? 2 : 1;
> Index: auto_mask.c
> ===================================================================
> --- auto_mask.c    (revision 40418)
> +++ auto_mask.c    (working copy)
> @@ -61,7 +61,9 @@
>    return 0;
>    }
>
> -    Rast_unopen(R__.mask_fd);
> +    if (R__.mask_fd >= 0)
> +    Rast_unopen(R__.mask_fd);
> +      R__.mask_fd = Rast__open_old("MASK", G_mapset());
>    if (R__.mask_fd < 0) {
>    R__.auto_mask = 0;
>
> Alternatively, just return if a raster map can't be unopened/closed?
>
> Markus M
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