madvise - Advise the system of the expected paging behavior
of a process
#include <sys/types.h> #include <sys/mman.h>
int behav );
Specifies the address of the region to which the advice
refers. Specifies the length in bytes of the region specified
by the addr parameter. Specifies the behavior of
the region. The following values for the behav parameter
are defined in the <sys/mman.h> header file: No further
special treatment Expect random page references Expect
sequential references Will need these pages Do not need
The system will free any whole pages in the specified
region. All modifications will be lost and any
swapped out pages will be discarded. Subsequent
access to the region will result in a zero-fill-ondemand
fault as though it is being accessed for the
first time. Reserved swap space is not affected by
this call. Ensure that resources are reserved
The madvise() function permits a process to advise the
system about its expected future behavior in referencing a
mapped file or shared memory region.
Only a few values of the behav parameter values are operational
on Tru64 UNIX systems. Non-operational values cause
the system to always return success (zero).
Upon successful completion, the madvise() function returns
zero. Otherwise, -1 is returned and errno is set to indicate
If the madvise() function fails, errno may be set to one
of the following values: The behav parameter is invalid.
The behav parameter specifies MADV_SPACEAVAIL and
resources cannot be reserved.
Functions: mmap(2), nmadvise(3)
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