[openbeos] Re: mmap, vm2 and you

  • From: Rudy Gingles <rudyatek@xxxxxxxxxxxxxx>
  • To: <openbeos@xxxxxxxxxxxxx>
  • Date: Thu, 5 Sep 2002 18:34:36 -0700

>Anyway. What I wanted to ask you all is this - does anyone know of
>MAP_COPY or MAP_PRIVATE being used in real software? I can write
>cases for them, but it is more work and I thought that I would ask
>and see if anyone knows of people actually using them. It somewhat
>complicates things (and they are slower than their more public

I always saw mmap as private, until it was specifically shared, in 
which case you are correct about keeping all changes in real-time.

As far as MAP_COPY, the only big usage that comes to mind is POSIX 
and fork(). But even elsewhere, technically, there could be many 
cases where you pass a buffer to another app, and use MAP_COPY rather 
than specifically making a copy yourself. Just an idea.


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