Other mapping functions
long
sysconf(PAGESIZE);
sysconf
returns the system-dependent size of a memory page.
For portability,
applications should not embed any constants specifying the size of a page, and
instead should make use of
sysconf
to obtain that information.
Note that it is not unusual for page sizes to
vary even among implementations of the same instruction set, increasing the
importance of using this function for portability.
int
mprotect(caddr_t addr, size_t len, int prot);
mprotect
has the effect of assigning protection
prot
to all pages in the range
[addr, addr + len).
The protection assigned can not exceed the permissions allowed on the
underlying object.
For instance, a read-only mapping to a file that was
opened for read-only access can not be set to be writable with
mprotect
(unless the mapping is of the
MAP_PRIVATE
type, in which case the write access is permitted since the writes will modify
copies of pages from the object, and not the object itself).
Next topic:
Address space layout
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Memory page residency
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 27 April 2004