fadvise man page on HP-UX

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fadvise(2)							    fadvise(2)

NAME
       fadvise() - file advisory information

SYNOPSIS

   Parameters
       fad_fd	      The  open file descriptor to which the fadvise operation
		      applies.

       fad_offset     The beginning of the specified range as a positive, byte
		      offset.

       fad_len	      The length of the specified range in bytes.

       fad_advice     Specifies	 advice	 to  be	 applied  to  range  (see fad‐
		      vise(5)).

       fad_extparms   Pointer to an array of (see fadvise(5)).

DESCRIPTION
       The function is used to advise the system about the  expected  behavior
       of the application with respect to the data in the file associated with
       the open file descriptor, fad_fd, starting at fad_offset and continuing
       for fad_len bytes.  The specified range need not currently exist in the
       file.  If fad_len is zero, all data following fad_offset is specified.

       The interpretation of the fad_offset and fad_len parameters are	condi‐
       tional  in that they are ignored in the case of a non-null fad_extparms
       argument.  If non-null, the fad_extparms argument is used as a  pointer
       to an extended parameter list of type (see fadvise(5)).

       The  extended  parameter list allows an application to batch hints over
       multiple ranges in one call.  The fad_count items are processed in list
       order  where,  in  the case of overlapping ranges, entries lower on the
       list of hints take precedence.

       It should be noted that the effect of all hints	is  cumulative	for  a
       given  file  object.   All hints will be removed on processing the last
       close of the file object.

       The fad_advice parameter is used to convey the hint to  be  applied  to
       the data and may be one of the following values:

       The  cc-numa  related policies are to be used by VM for physical memory
       locality when allocating memory for file I/O.  This  attribute  applies
       to the entire file only.

	      Either  one  of  the following policies can be combined with the
	      command (for further reference see fadvise(5):

	      Policy specifying that memory for the file will be allocated
		     from interleaved memory.  Interleaved  memory  is	memory
		     allocated	from several locality domains and then striped
		     together. It should be used if equal-cost allocations are
		     needed.

	      Policy specifying that memory for the file will be allocated
		     from the locality of the calling CPU. Fast when memory is
		     available from the closest locality otherwise  search  by
		     distance for available memory to allocate.

       Specifies that the application will expect that it will not
	      access the specified range of data in the near future.

       The application prefers that large pages be used
	      by  VM  in  allocating  memory for file I/O.  The preferred page
	      size is passed in the fad_pgsize alias  (see  fadvise(5)).   The
	      page size specified in the fad_pgsize alias will be rounded down
	      to the supported large page size in the system.  If no  hint  is
	      specified,  then	the page size specified in the tunable will be
	      used.

       Specifies that the application will  expect  to	access	the  specified
       range
	      of data once and then not reuse it thereafter.

       Specifies that the application has no advice to give on its behavior
	      with  respect  to the specified data.  It is the default charac‐
	      teristic if no advice is given for an open file.

       Specifies that the application will expect to access the specified
	      specified range of data in a random order.

       Specifies that the application expects to access the specified range of
       data
	      sequentially from the lower offsets to higher offsets.

       No pages associated with given
	      fd should be sync'd by VM.

       Sets paging policies used by the VM syncer for a
	      fd  when	selecting  pages  for page out.	 This policy indicates
	      that pages associated with file i/o should be sync'd in  a  time
	      interval	designated by the fad_synctime alias (see fadvise(5)).
	      This is default behavior with time interval set by VM.

       Specifies that the application will expect to access the specified
	      range of data in the near future.

       These values will be defined in

RETURN VALUE
	      Successful completion.
	      Failure.
		     is set to indicate the error.

ERRORS
       If the service fails, is set to one of the following values:

       The	      fd argument is not a valid file descriptor.

       The value of   fad_advice or one of the other  input  values  has  been
		      found to be invalid.

       A designated hint is not supported by the underlying file object.

       The fadvise operation is not supported by the underlying file system.

       The	      fd argument is associated with a pipe or FIFO.

       If  an  error  is detected while processing a given fad_advice hint, an
       error number will be returned indicating the  related  error  (see  The
       error  number  value,  therefore,  is  independent of the error numbers
       listed above.

EXAMPLES
AUTHOR
       was derived by HP from the IEEE POSIX 1003.1-2001 Standard.

SEE ALSO
       fcntl(2), posix_fadvise(2), fadvise(5), fcntl(5).

STANDARDS CONFORMANCE
								    fadvise(2)
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