Re: [boost] [interprocess] semantics of mmap()d files on network filesystems

From: Sebastian Redl (sebastian.redl_at_[hidden])
Date: 2007-09-14 13:36:47

Phil Endecott wrote:
> Does anyone have any ideas about the behaviour of memory-mapped files 
> on network filesystems, i.e. NFS and/or Windows shares?  Is there any 
> chance that Boost.Interprocess could use mmaped files on such 
> filesystems, with instances of the program running on different 
> machines sharing data?
>   
MSDN has this to say for CreateFileMapping:
> Although *CreateFileMapping* works with remote files, it does not keep
> them coherent. For example, if two computers both map a file as
> writable, and both change the same page, each computer only sees its
> own writes to the page. When the data gets updated on the disk, it is
> not merged.

Although I couldn't find concrete information in the man pages, some
Google results on "mmap consistent" suggest that mmap behaves the same.

Sebastian Redl