Hi, ----- Original Message ----- From: "Phil Endecott" <spam_from_boost_dev@chezphil.org> To: <boost@lists.boost.org> Sent: Saturday, April 25, 2009 4:13 PM Subject: Re: [boost] Boost.Process article: Tutorial and request for comments
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.
Yes, this seems much more efficient. So the Process library should use the environement filed as a list of environment variable to set on the child process.
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.
I agree that the default must inherit the environement variables, no need to state this explictly, not need to copy it.
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.
I agree again. Best, Vicente