Re: Question about memory-mapped files

[Hugh Dickins]

On Wed, 28 May 2003, John M Collins wrote:
> 
> If I invoke mmap to map a file to memory, and it succeeds, can I safely 
> close the original file descriptor and rely on the memory still being 
> mapped and the file still updated (possibly with mysnc)?

Yes, that's definitely a part of the specification of mmap,
even if it's not mentioned on the man page.

Note that the file on disk is likely not to be updated until
some time after you unmap it, unless you use msync to force it.

Hugh