Re: clearing the environment

On Sun, Jun 3, 2012 at 10:24 AM, Laurent Bercot
<[email protected]> wrote:
>> So, if I understood right, we shouldn't use clearenv() or equivalent and then
>> setup a few variables, but rather build from scratch an array an pass it to
>> execve. Is there some issue with clearenv, e.g. related with memory leaking?
>
>  putenv() and friends were made to modify the environment within the same
> process, without execve'ing. It requires some hidden memory allocations,
> it's inefficient, and unless you're coding a shell, it's mostly useless.
>

Thanks for the explanation, it's hard to find this kind of stuff in the net.

>  Since you can afford to execve(), it's much simpler to just setup a new
> environment array and pass it to execve(). You *can* use putenv(), or
> heap memory allocation, and just not care about memory leaks, since
> execve() will clean up everything anyway; but you don't need to - and you
> certainly don't need to if all you want is clear the environment.
>
>  Btw, don't pass NULL to execve(). Pass char const *envp[1] = { NULL }.
>
Actually, I want to clear the environment and then set two variables, so I
have a 3 elements array.

Cheers

Jorge