From: "Mark E." <snowball3 AT bigfoot DOT com>
To: djgpp-workers AT delorie DOT com
Date: Mon, 28 May 2001 16:00:13 -0400
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Subject: Re: confstr implementation
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> >     case _CS_PATH:

BTW, one problem I just noticed in the Posix draft is that confstr() names 
the symbol '_CS_PATH', while in unistd.h it names the symbol 
'_CS_POSIX_PATH'.

> >     {
> >       char *djdir = getenv("DJDIR");
> >       if (djdir)
> >         out_len = snprintf(buf, len, "%s/bin", djdir);
> 
> I wonder: is this in the spirit of what Posix says?  What if DJDIR is
> changed during the program's run?  Posix seems to indicate that
> _CS_PATH should return the original value that is unaffected by
> user-level changes.

In the April 2001 draft, the standard wants whatever path is returned to 
point to the utilities:
The confstr( ) function with a name argument of _CS_PATH returns a string 
that can be used as a PATH environment variable setting that will reference 
the standard shell and utilities as described in the Shell and Utilities 
volume of IEEE Std 1003.1-200x.

But the draft does say its original use is much like the language you point 
out:
The original need for this function was to provide a way of finding the 
configuration-defined default value for the environment variable PATH. Since 
PATH can be modified by the user to  include directories that could contain 
utilities replacing the standard utilities in the Shell and  Utilities volume 
of IEEE Std 1003.1-200x, applications need a way to determine the system-
supplied PATH environment variable value that contains the correct search 
path for the standard utilities.

> So perhaps we need something in the startup code which will stash away
> the value of DJDIR as seen by the startup code.

I'm tempted to say this is overkill because DJDIR isn't supposed to be 
changed by the user. But just because folks shouldn't doesn't mean they 
won't.

> Btw, shouldn't we introduce into the system headers some new
> preprocessing symbols which distinguish between the old Posix standard
> and the new one?

The new Posix specifies some additional preprocessing symbols: 
_POSIX2_VERSION by unistd.h and _POSIX_C_SOURCE presumably by 'gcc --posix'.

BTW, the April 2001 draft can be downloaded from:
http://anubis.dkuug.dk/JTC1/SC22/open/n3232/

Mark