Re: [aspell-devel] Multi-user aspell usage.

[Christoph Hintermüller]

Hi
Am Dienstag, 1. Februar 2005 22:40 schrieb Kevin Atkinson:
> > > MMAP might work with Cygwin.  However if you are using Aspell 0.60 than
> > > you don't need to worry about it as much as Aspell 0.60 will cache
> > > instances of the dictionary class and reuse them.  Thus multiple copies
> > > will not be used.
> > >
> > Please forgive me if I misunderstand the topic, but I want make
> > sure you understand that Windows program will not share memory
> > unless a server, or service has been defined. I've only seen the
> > aspell library defined as a dll, and a dll will create new
> > objects for each instance of the application.
Have a look a CreateFileMapping and CreateMappedFileView or so they are the 
windows native alike to mmap. Allthough the mapping objects or better the 
virtual address range the file(s) appera within the addresspace of each 
program is different. The physical memorypages the operating system assigns 
to the file content are the same. The mechanisms are the same as used for 
swap file. Thus under windows you may consider the mapped files or parts of 
them to be a temporary extension to swap file. In read only mode the mapped 
files have the advantage that the physical pages occupied may be overwritten 
by os without the need writing them to file ;-). The other way you could 
consider swap file a special memory mapped file which is opened in random 
read write mode only accessible exclusively by the operating system. ;-)

So far a rough not precise description of memory mapped io and what classes 
take care of in native windows developement.
cu
Xris