Re: [boost] [interprocess][process] Synchronizing libraries and efforts (+ bugs)

From: Boris (boriss_at_[hidden])
Date: 2008-09-01 14:41:36

On Mon, 01 Sep 2008 17:44:56 +0200, Ion Gaztañaga <igaztanaga_at_[hidden]>  
wrote:

> Boris wrote:
>>> -> Using named pipes has been problematic because it returns errors  
>>> when launching multiple processes aggressively: Error 231 - All Pipes  
>>> are Busy. This does not happen with anonymous pipes and I think it has  
>>> some relationship with the guid code. By the way, I think a uuid  
>>> library is too much to create a unique identifier to be shared with  
>>> the child a simple atomic count would to the job in my opinion. That  
>>> would reduce Boost.Process dependencies.
>>  An atomic count might not be sufficient as it would be unique only per  
>> process. As I used Boost.Uuid only for convenience though I'll replace  
>> it with an atomic count plus a random number to drop the dependency.
>
> The PID of the parent plus an atomic count wouldn't be enough?

I had the same idea first. But as the pipe class doesn't know the PID in  
the process class I thought a random number should be fine, too. However  
we can call of course getpid() and a Windows function if you prefer not to  
use a random number.

>>> -> systembuf::close() should call sync() to push the last charaters  
>>> into the pipe, othewise, characters are lost if the user does not  
>>> flush the stream.
>>  Changed (in postream::close()).
>
> I think we must change this in systembuf, because a user might use the  
> streambuf directly and it would be surprised to see that unlike  
> std::filebuf, already written characters are missed.

Ah, I thought it was a typo as there is no close() method in systembuf. As  
systembuf is derived from std::streambuf which doesn't provide close()  
either I was pretty sure you meant postream::close()?

Boris