Re: [boost] [gsoc] Boost.Process done

Subject: Re: [boost] [gsoc] Boost.Process done
From: Boris Schaeling (boris_at_[hidden])
Date: 2010-09-11 18:15:16

On Sat, 11 Sep 2010 23:24:32 +0200, Jeremy Maitin-Shepard  
<jeremy_at_[hidden]> wrote:

> On 09/11/2010 01:51 PM, Jeremy Maitin-Shepard wrote:
>> On 09/11/2010 01:32 PM, Boris Schaeling wrote:
>> [snip]
>
>>> Please have a look at
>>> <http://svn.boost.org/svn/boost/sandbox/SOC/2010/process/libs/process/example/file_descriptors_setup.cpp>.
>>>
> [...]By the way, the example is quite possibly not even correct, because  
> file descriptors 3 and 4 might already be in use, and therefore  
> depending on the order of operations (and the relative order of  
> context::setup and boost process's internal file descriptor setup) the  
> code may do the

You are right. If I remember correctly the example isn't tested yet (it  
was converted from an example from a previous Boost.Process version).

> wrong thing.  That is why all of the file descriptor setup has to be  
> coordinated, and therefore why boost process needs to provide an  
> interface for doing it.

The interface is context::setup(). The method is called after fork() and  
before execve() in the child process only (on POSIX). When  
context::setup() is called (only) the standard streams have been  
configured and you can do whatever you like with file descriptors  
inherited from the parent process. This has also been tested in  
<http://svn.boost.org/svn/boost/sandbox/SOC/2010/process/libs/process/test/child.cpp>  
(search for "BOOST_AUTO_TEST_CASE(test_posix)"). If you think this test  
case misses something I'd be happy to add another one.

Boris