mnesia

[Ulf Wiger]

Ulf Wiger wrote:
> 
> 
> Setting the environment variables programmatically *can* be done, but
> you have to use an internal function in the application_controller:
> 
>         application_controller:set_env(AppName, Key, Value)
> 
> It is not recommended, and you will not find the function in any manual.
> 

Ok, confession time. ;)
I *have* done this myself in production code:


	patch_load_mnesia(Dir) ->
	    application:load(mnesia),
	    application_controller:set_env(mnesia, dir, Dir).

After this, you may issue application:start(mnesia).

I do this in an installation program, which also configures a start
command and a sys.config file. After that, all parameters are set
correctly every time the system is started.


However, there is also a function, mnesia:start(ExtraEnv), which does
the same thing. It is not official either, so I guess it's just a matter
of choosing your favourite undocumented feature and running with it. ;)

I still recommend messing with the env variables at installation only,
and not afterwards.


/Uffe
-- 
Ulf Wiger, Chief Designer AXD 301     <ulf.wiger@REDACTED>
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