From: Brian Candler <b.candler@...>
Date: 2009-02-09T22:02:42+09:00
Subject: Re: assignment to $stdout deprecated?

7stud -- wrote:
> AFAIK, all child processes receive a copy of their environment including 
> copies of all the variables in the parent.

Starting a different child process, such as a shell, involves fork() 
followed by exec() in the child.

Immediately after the fork(), the child will have a copy of everything 
the parent has, including the file descriptor table.

It then has the opportunity (if it wishes) to clean up the FD table 
before calling exec(), and/or to pass a different environment or 
arguments to the program which it is exec()ing.

> So echo doesn't write to 
> $stdout because echo doesn't understand ruby and therefore ignores 
> variables like $stdout?

Basically, yes. echo just writes to FD 1. It doesn't know anything about 
Ruby or Ruby objects. Indeed since Ruby is running in a different 
process, it cannot possibly access them (other than via some sort of 
IPC, e.g. communicating over a pipe)

Regards,

Brian.
-- 
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