Re: [boost] [test] PATCH: putenv usage incorrect

From: Caleb Epstein (caleb.epstein_at_[hidden])
Date: 2005-04-26 13:44:37

On 4/26/05, Martin Wille <mw8329_at_[hidden]> wrote:
> Caleb Epstein wrote:
> > On 4/26/05, Martin Wille wrote:
> >
> 
> [...]
> 
> >>setenv() is a very recent addition to POSIX, IIRC. Older Unix versions
> >>might not support it.
> >
> >
> > OK, would you know of a better way to determine which "type" of putenv
> > is available instead?  E.g. is it the one that takes a const char* and
> > copies, or the one that takes a char* and inserts it into the
> > environment in-place.  Using the wrong semantic will lead to either
> > memory leak (bad) or undefined behavior (worse).
> 
> I once wrote my own version of putenv() in order to avoid the memory
> leak problem. I'm afraid this is a nasty problem, because POSIX putenv()
> doesn't copy but doesn't assume ownership, either. setenv() might leak
> for that reason, too.
> 
> You can check for the platforms you know to support setenv by using the
> various macros they supply (messy, I know). Every *BSD I know of and
> Linux do. setenv() was added to POSIX in IEEE Std 1003.1-2001, if I
> understand correctly. So setting _POSIX_C_SOURCE before #including any
> POSIX header and checking for _POSIX_VERSION >= 200112L should catch all
> POSIX implementations that added setenv() recently.
> 
> [...]
> 
> >>Your patch doesn't check the value returned by setenv() or putenv().
> >
> >
> > Nor did the original.  I'm just trying to get this code working in
> > order to clear up some of the test failures.
> 
> Well, I don't know the context of the code. I can't say whether it is ok
> to ignore the result here. I just wanted to state what I've seen.

Perhaps Genndiy could comment on whether or not this code is really
even needed.  It seems to  only be used in a single test program.

-- 
Caleb Epstein
caleb dot epstein at gmail dot com