[GRASS-dev] Access to mapset environment variable

[Sören Gebbert]

Hi,

2014-09-04 23:04 GMT+02:00 Glynn Clements <glynn at gclements.plus.com>:
>
> Sören Gebbert wrote:
>
>> > > I am struggling to access GRASS mapset specific environmental
>> > > variables from mapsets different than the current one in C.
>> > ...
>> > > Is there a possibility to access mapset specific environmental
>> > > variables in C from a different mapset as the current one?
>> >
>> > Hi,
>> >
>> > I would suggest to use the mapsets' VAR file, not gisrc (g.gisenv),
>> > to store per-mapset variables like that. Since gisrc is per-session
>> > and ephemeral, not per-mapset and remembered after the session is
>> > closed.
>>
>> Actually that is exactly what i am trying to do. So my question is how to
>> convince grass to read the VAR file from a mapset other than the current
>> one without invoking g.mapset.
>
> Currently, you can't. G__gisinit() calls G_init_env() which reads both
> environment files into memory. The functions which read these files
> will not attempt to read them again if they're already in memory.
>
> You would need to modify lib/gis/env.c to allow the "VAR" environment
> to be forcibly re-read (and without first re-reading the "gisrc"
> environment, as that will restore the original current mapset).#

Thank you for this clear answer. I have implemented a patch to allow
force reading
of mapset VAR and gisrc files in libgis[1] including some tests. I
would like to submit it in the next week, if there are no objections
against the patch?

Best regards
Soeren

[1] http://trac.osgeo.org/grass/ticket/2408

>
> --
> Glynn Clements <glynn at gclements.plus.com>