Re: [boost] [iostreams][1.44] file_descriptor constructor deprecated

Subject: Re: [boost] [iostreams][1.44] file_descriptor constructor deprecated
From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2010-09-09 09:37:30

> On 9 September 2010 13:11, Hartmut Kaiser <hartmut.kaiser_at_[hidden]>
> wrote:
> >
> > Why has the iostreams::file_descriptor constructor taking a file
> > descriptor (OS handle) being deprecated
> > (BOOST_IOSTREAMS_USE_DEPRECATED)? This seems to be somewhat
> > counter-intuitive to me. Even more as our code depends on this
> > functionality and I see no way to rewrite it in order to accommodate for
> this change (we're wrapping a pipe handle here).
> 
> There are new constructors which provide equivalent functionality.
> They're mentioned in both the release notes and the documentation. The
> problem is that the class' close method would close the file descriptor
> regardless of whether 'close_on_exit' was set. This meant the file
> descriptors could be unexpectedly closed because iostream calls 'close'
> elsewhere. It could be changed so that if 'close_on_exit' is false, then
> close wouldn't close the file descriptor - but it's very likely that
> there's existing code which relies on the file descriptor getting closed
> so that would cause resource links. So the new constructors require you to
> be explicit about whether you want the class to close the file descriptor
> or not.

Ok, that makes sense. Thanks for the explanation. I have not seen the new
constructors, so I apologize for the noise.

> > The worst is that defining BOOST_IOSTREAMS_USE_DEPRECATED while
> > compiling our application makes the compilation succeed, but linking
> > fails as this function has not been compiled by default into the
> iostreams library.
> > Regenerating the boost libraries is not an option for us, as we need
> > to rely on pre-installed libraries most of the time (HPC systems have
> > their own weird rules...).
> 
> How are you building it? The macro is defined in the iostreams Jamfile.

Hmmm, that's strange. We just built it using bjam. I'll need to get back to
this to check what's going on.

Regards Hartmut
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