Subject: Re: MAP_FILE in /usr/include/sys/mman.h
To: current-users <current-users@sun-lamp.cs.berkeley.edu>
From: Scott Reynolds <scottr@Plexus.COM>
List: current-users
Date: 07/20/1994 10:26:01
cgd> MAP_FILE shouldn't be used; it's been deprecated. mmap() now
cgd> considers things files, unless specified otherwise.
Well, OK, I'll buy this, but there are two things that point to the need
for MAP_FILE... in /usr/include/sys/mman.h there *is* a reference to the
non-existent MAP_FILE value, and in mmap(2) it's explicitly named. If
the default behavior is MAP_FILE, then it seems that both the .h and
manpage need to be changed. Also it's not very clear exactly what should
be used in place of something like this:
base = (pointer)mmap(..., MAP_FILE, ...);
From looking at mman.h I would suspect that it's now "proper" to specify
one of MAP_SHARED, MAP_PRIVATE, or MAP_COPY. Is this correct? If none of
these is specified, which, if any, is the default? Not being very
familiar with the internals of the vm system, things got pretty hairy
when I tried to figure out for myself in vm/vm_mmap.c...
--scott
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