Experimental Physics and
Industrial Control System

On Apr 14, 2021, at 11:13 AM, Ralph Lange via Core-talk <core-talk at aps.anl.gov> wrote:
>
> AppData is one of quite a few standard Windows variables. Obviously, introducing my own variables would work and make the whole thing non-portable.
>
> The getenv() call works just fine, mixed paths work fine, I can read directly from the environment and have utilities that convert forward to backslashes etc etc.
> The one and only real show stopper is that the iocShell's macro expansion changes the value of those standard environment variables when you use them.

Even epicsEnvSet preserves back-slashes in the values it sets. The macLib routines are supposed to preserve strings inside single quotes, but then they don’t expand the macros inside. I just experimented with various ways of quoting stuff, but that doesn’t seem to help at all: 

[...]
> epics> epicsEnvSet eeed '\\\"'       
> epics> epicsEnvShow eeed             
> eeed=\\\"
> epics> echo "$(eeed)$(APPDATA)$(eeed)"
> Unbalanced quote.


That last error (from iocsh, not macLib) is interesting, but probably not useful.

Do we need some syntax in macros to prevent them from escaping back-slashes when expanding values?  I’m not sure how easy it would be to implement that, but it might be possible. Any other suggestions on what might be changed?

    /* discard quotes and escapes if level is > 0 (i.e. if these aren't

       the user's quotes and escapes) */