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madvise(2)
NAME
  madvise - 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
  addr	  Specifies the address of the region to which the advice refers.

  len	  Specifies the length in bytes of the region specified by the addr
	  parameter.

  behav	  Specifies the behavior of the region. The following values for the
	  behav parameter are defined in the <sys/mman.h> header file:

	  MADV_NORMAL
		  No further special treatment

	  MADV_RANDOM
		  Expect random page references

	  MADV_SEQUENTIAL
		  Expect sequential references

	  MADV_WILLNEED
		  Will need these pages

	  MADV_DONTNEED
		  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.

	  MADV_SPACEAVAIL
		  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. Otherwise,
  -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 following
  values:

  [EINVAL]
	  The behav parameter is invalid.

  [ENOSPC]
	  The behav parameter specifies MADV_SPACEAVAIL and resources cannot
	  be reserved.

SEE ALSO
  Functions: mmap(2), nmadvise(3)

Index for Section 2

Alphabetical listing for M

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