Subject: Re: [boost] Boost.Process article: Tutorial and request for comments
From: Phil Endecott (spam_from_boost_dev_at_[hidden])
Date: 2009-04-25 10:13:16
Boris Schaeling wrote:
> On Tue, 21 Apr 2009 20:15:11 +0200, Phil Endecott wrote:
>> Re the environment: I'm not enthusiastic that you have copied the
>> environment into your own data structure. Why can't your environment
>> type just wrap getenv() and setenv()? i.e.
> The type environment is also used to setup a new environment for a child
> process, eg.:
>
> context ctx;
> ctx.environment.insert(environment::value_type("PATH", "/newpath"));
> launch(..., ctx);
Typically I would write:
fork();
setenv("PATH","/newpath");
exec();
So the new child process gets the parent's environment with any new
variables added or changed. This seems a lot simpler than copying the
whole environment.
>> Why don't you boil it down to:
>>
>> launch_process("notepad.exe");
>
> Currently the environment variables of the current process are not
> automatically inherited by a child process. I agree that it should be
> easier to launch a new process. But then environment variables should
> probably be inherited by default?
The environment is inherited across fork() and all those versions of
exec() that don't explicitly set a new environment.
>>> it is very important to refer to the executable with an absolute path -
>>> on all platforms including POSIX systems
>>
>> Why do you say that?
>
> It's a requirement of Boost.Process. It doesn't need to be an absolute
> path but can also be a relative path of course.
Right, so it doesn't need to be an absolute path.
> What's not guaranteed
> though is that an executable is automatically found when only a filename
> is given. There is a function which searches for an executable and returns
> an absolute path. Would you like to see Boost.Process search for an
> executable automatically?
No, I'd like to see it use one of the versions of exec() that does this
for you.
Regards, Phil.