Re: [Boost-users] [Interprocess] error_code_t = 9 (already_exists_error) while opening a fixed_managed_shared_memory

Subject: Re: [Boost-users] [Interprocess] error_code_t = 9 (already_exists_error) while opening a fixed_managed_shared_memory
From: Marsh Ray (marsh_at_[hidden])
Date: 2011-05-19 12:10:06

On 05/19/2011 10:52 AM, Gaetan Gaumer wrote:
>
> So I have two questions :
> 1) Do you have an idea why the mmap function maps the segment at a
> different address from the provided one, knowing that this address
> is the one returned from code below on another process (so should be valid) ?

Perhaps that address space was already being used by something. This is 
likely to be the case with large regions on a 32-bit OS.

How large is is the segment you're trying to map?

Is your process running as 64- or 32-bits?

> 2) In the mapped_region constructor, when a non null address value is
> given as a parameter, could we use the MAP_FIXED flag  to force
> the mmap function to map the segment at the provided address ?

What happens if something else is already at that address?

- Marsh