Re: [boost] [Serialization] Bizarre bug

Subject: Re: [boost] [Serialization] Bizarre bug
From: Peter Dimov (pdimov_at_[hidden])
Date: 2009-08-11 05:06:12

Robert Ramey wrote:
> The problem only occurs when program 1 contains only
>
> ar << T
>
> and program 2 contains
>
> ar >> T
> and
> ar >> Tptr
>
> But if only program 2 contains ar >> Tptr - how does the
> archive it's supposed to read get created?  It can be only
> created by a program which also contains ar << Tptr. That
> is in order for serialization to make any sense at all both
> programs have to  contain exactly the same sequence of
> loads and saves.  Hence. they will both either serializations
> for the same set of types at compiler time.
>
> The only case where this can occur is where the program
> is changed after an archive is created.  And even then it
> takes some effort to produce.

The other case in which this occurs is when program 2 needs to read archives 
from both program 1 and program 3 (containing ar << TPtr).

> In the IPC case, the program could only occur when
> the recieving program is a later version of the sending version.
> That is the same problem - reading an old archive version.

And you are saying that old archive versions are not supposed to be 
readable?