Re: [boost] [interprocess] shared memory map only working with built-in types?

From: Darren Garvey (darren.garvey_at_[hidden])
Date: 2008-06-15 15:30:41

Hi Ion,

2008/6/15 Ion Gaztañaga <igaztanaga_at_[hidden]>:

> Darren Garvey wrote:
>
>> Hello Ion,
>>
>> Title says it all really: the attached mini-program gives me a
>> segmentation
>> fault on ubuntu linux 8.04 with gcc 4.2.3 when trying to read back the
>> shared memory between process invocations (trying a similar program on XP
>> also fails).
>>
>
> The problem is that you are trying to put a type (std::string) that is not
> ready for shared memory or memory mapped files because:
>
> 1) it surely uses internal raw pointers
> 2) allocates memory from the heap instead of from the shared memory
>
> That's why Interprocess offers its own containers. See documentation about
> those containers and also try to see some tests where interprocess
> basic_string is being used. That will give you some clues on how to use
> strings in shared memory.

It all works a charm with interprocess::basic_string<>. Great! I didn't
notice that initially - even though I now see it's clearly documented in the
header reference... Perhaps a quick mention of the supported containers from
the "creating vectors/maps in shared memory" section would be helpful?

Anyway, thanks for the pointers (no pun intended).

Darren