madvise(2)madvise(2)NAMEmadvise - Advise the system of the expected paging behavior of a
process
SYNOPSIS
#include <sys/types.h> #include <sys/mman.h>
int madvise(
caddr_t addr,
size_t len,
int behav );
PARAMETERS
Specifies the address of the region to which the advice refers. Speci‐
fies 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 ref‐
erences Will need these pages Do not need these pages
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-on-demand 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
DESCRIPTION
The madvise() function permits a process to advise the system about its
expected future behavior in referencing a mapped file or shared memory
region.
NOTES
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).
RETURN VALUES
Upon successful completion, the madvise() function returns zero. Other‐
wise, -1 is returned and errno is set to indicate the error.
ERRORS
If the madvise() function fails, errno may be set to one of the follow‐
ing values: The behav parameter is invalid. The behav parameter speci‐
fies MADV_SPACEAVAIL and resources cannot be reserved.
SEE ALSO
Functions: mmap(2), nmadvise(3)madvise(2)
